Dietary Fiber Is Bad for Sex – That’s the Only Claim About It That Isn’t a Myth

Bran CerealToday’s article is a guest post from Konstantin Monastyrsky of In keeping with the mission statement of Mark’s Daily Apple to investigate, discuss, and critically rethink everything we’ve assumed to be true about health and wellness, I like to periodically give credible researchers who are challenging conventional wisdom the opportunity to share their insights and findings here. It’s a great way to open a dialogue on topics that deserve challenging. Like fiber, for instance. Everyone knows that fiber is good for you, right? Well, let’s find out what Konstantin—a guy who’s spent an incredible amount of time researching this topic—thinks about this truism. Enter Konstantin…

Does dietary fiber contain anything of nutritional value? No, it doesn’t. Zero vitamins… Zero minerals… Zero protein… Zero fat… Nothing, zilch, not even digestible carbohydrates. Why, then, is it considered a healthy nutrient? As the story goes, you can thank Dr. John Harvey Kellogg for that:

“Dr. Kellogg was obsessed with chastity and constipation. True to principle, he never made love to his wife. To “remedy” the sin of masturbation, he advocated circumcision without anesthetic for boys, and mutilation of the clitoris with carbolic acid for girls. He blamed constipation for “nymphomania” in women, and lust in men, because, according to Kellogg, impacted stools inside one’s rectum were stimulating the prostate gland and the female vagina into sexual proclivity.” [link]

To fix these “ailments,” Dr. Kellogg was prescribing a coarse vegetarian diet along with 1 to 3 ounces of bran daily, and mineral oil with every meal. As any nutritionist will tell you, the decline of libido and infertility are among the very first symptoms of malnutrition prevalent among ardent vegans. And in this particular case, extra bran and mineral oil were “enhancing” damage by blocking the assimilation of nutrients from an already meager diet.

And what was Dr. Kellogg’s rationale for prescribing mineral oil? Well, because so much fiber was enlarging stools, intense straining was required to expel them. The oil was used as a lubricant to reduce pain caused by straining, and to prevent bloody anal fissures inside the anal canal.

However, the ultimate fame and money came to Dr. Kellogg not from crusading against sex, but from ready-to-eat morning cereals after he found that baking bran into cereals proved to be incredibly profitable for Kellogg Company. From that point on, it took another sixty years or so of relentless brainwashing to turn what once used to be a dirt-cheap livestock feed into a premium health food.

Well, that’s an old story, and I can understand if you doubt it—it sounds too incredulous to be true! So, let’s debunk fiber’s mythology with facts and science. Here we go, one myth at a time:

Myth #1: For maximum health, obtain 30 to 40 g of fiber daily from fresh fruits and vegetables.

Reality: Here is how many fresh fruits you’ll need to eat throughout the day in order to obtain those 30 to 40 grams (1-1.4 oz.) of daily fiber:

Daily Fiber in Fruit

As you can see, that comes to five apples, three pears, and two oranges. A small apple contains 3.6 g of fiber and 15.5 g of sugars. A small pear—4.6 g and 14.5 g; and a small orange—2.3 g and 11.3 g, respectively (USDA National Nutrient Database; NDB #s: 09003; 09200; 09252 [link]).

These ten small (not medium or large) fruits will provide you with 36.4 g of indigestible fiber and a whopping 143.6 g of digestible sugars, or an equivalent of that many (ten) tablespoons of plain table sugar!

Ten Spoons of Sugar

And that‘s before accounting for all the other carbs consumed throughout the day for breakfast, lunch, dinner, and from snacks and beverages.

So ask yourself this question: even if you are a 100% healthy 25-year-old muscle-bound athlete, would you ever ingest that much sugar willingly? Well, maybe under the influence of a controlled substance or torture…

But that’s exactly what’s being recommended for “health purposes” to children and adults. It‘s not surprising that so many Americans are suffering from the ravages of diabetes and obesity—a moderately active adult can utilize no more than about 200 grams of carbohydrates per day without encountering a scourge of the inevitable obesity, prediabetes, or diabetes.

The ratio of digestible carbohydrates (sugars) to fiber in vegetables, cereals, breads, beans, and legumes is, on average, similar to fruits. Thus, no matter how hard you try to mix’n’match, you’ll be getting harmed all the same.

Please do note that if you are healthy, active, and normal weight, there is nothing wrong with consuming fruits and vegetables in moderation. The point of this section is to impress on you that it is NOT OK to binge on fruits to ingest recommended daily intake of fiber.

This myth—that fruits and vegetables are the best source of dietary fiber—is probably the most pervasive and damaging of all. If 30 grams of fiber is what you’re really after, you’re better off getting it from supplements. These, after all, have almost no digestible carbs. But, then, of course, you run into those other persistent falsehoods…

Myth #2: Fiber reduces blood sugar levels and prevents diabetes, metabolic disorders, and weight gain.

Reality: That’s a blatant deception. If you consume 100 g of plain table sugar at once, the blood absorbs all 100 g of sugar almost as soon as it reaches the small intestine, where the assimilation takes place. If you add 30 g of fiber into the mix, the fiber may extend the rate of sugar assimilation into the blood, from, let‘s say, one hour to three.

But at the end of those extra three hours the blood will still absorb exactly the same 100 g of sugar—not an iota more, not an iota less. If you are a diabetic, the only difference will be that you‘ll require more extended (long-acting) insulin for type 1 diabetes, or larger doses of medication for type 2 diabetes in order to deal with slow-digesting sugars, and your blood glucose test will not spike as high after the meal.

But you‘re fooling no one but a glucose meter. In all other respects, the damage will be all the same, or even worse. And that‘s even before taking into account the negative impact of fiber on the digestive organs, or hyperinsulinemia and triglycerides on the heart, blood vessels, and blood pressure.

Myth #3: Fiber-rich foods improve digestion by slowing down the digestive process.

Reality: Fiber indeed slows down the “digestive process,” because it interferes with digestion in the stomach and, later, clogs the intestines the “whole nine yards.” The myth is that it can be good for health and the digestive process.

Here is what you get from delayed digestion: indigestion (dyspepsia), heartburn (GERD), gastritis (the inflammation of the stomach‘s mucosal membrane), peptic ulcers, enteritis (the inflammation of the intestinal mucosal membrane), and further down the chain, constipation, irritable bowel syndrome, ulcerative colitis, and Crohn‘s disease.

All this, in fact, is the core message of Fiber Menace: fiber slows down the digestive process! And slow digestion is ruinous for your health. Don‘t mess with fiber unless your gut is made of steel!

Myth #4: Fiber speeds food through the digestive tract, helping to protect it against cancer.

Reality: Not true. In fact, this claim directly contradicts the claim that fiber-rich foods slow down the digestive process. For a reality check, here’s an excerpt from a college-level physiology textbook that reveals the truth:

“Colonic Motility: Energy-rich meals with a high fat content increase motility [the rate of intestinal propulsion]; carbohydrates and proteins have no effect.”

R.F. Schmidt, G. Thews; Human Physiology, 2nd edition. 29.7:730 [link]

This, incidentally, is why low-fat diets and constipation commonly accompany each other. And don’t count on getting any cancer protection from fiber, either. That‘s yet another oft-repeated deception.

Myth #5: Fiber promotes a healthy digestive tract and reduces cancer risk.

Reality: Not true. Here’s what doctors-in-the-know have to say on the subject of the colon cancer/fiber connection:

Lack of Effect of a Low-Fat, High-Fiber Diet on the Recurrence of Colorectal Adenomas

“Adopting a diet that is low in fat and high in fiber, fruits, and vegetables does not influence the risk of recurrence of colorectal adenomas.”

Arthur Schatzkin, M.D et al. The New England Journal of Medicine; [link]

The excerpt below comes, of all places, from the Harvard School of Public Health:

Fiber and colon cancer

“For years, Americans have been told to consume a high-fiber diet to lower the risk of colon cancer—mainly on the basis of results from relatively small studies. Larger and better-designed studies have failed to show a link between fiber and colon cancer.”

Fiber: Start Roughing It [link]

Not convinced yet? Well, here is even more damning evidence from the U.S. Food and Drug Administration:

Letter Regarding Dietary Supplement Health Claim for Fiber With Respect to Colorectal Cancer

“Based on its review of the scientific evidence, FDA finds that (1) the most directly relevant, scientifically probative, and therefore most persuasive evidence (i.e., randomized, controlled clinical trials with fiber as a test substance) consistently finds that dietary fiber has no [preventive] effect on incidence of adenomatous polyps, a precursor of and surrogate marker for colorectal cancer; and (2) other available human evidence does not adequately differentiate dietary fiber from other components of diets rich in foods of plant origin, and thus is inconclusive as to whether diet-disease associations can be directly attributed to dietary fiber. FDA has concluded from this review that the totality of the publicly available scientific evidence not only demonstrates lack of significant scientific agreement as to the validity of a [preventive] relationship between dietary fiber and colorectal cancer, but also provides strong evidence that such a relationship does not exist.”

U. S. Food and Drug Administration – Center for Food Safety and Applied Nutrition Office of Nutritional Products, Labeling, and Dietary Supplements; [link]

Alas, the story doesn’t end there. Adding insult to injury, Chapter 10 of my book entitled Fiber Menace, “Colon Cancer” cites studies that demonstrate the connection between increased fiber consumption and colon cancer. Also, countries with the highest and lowest consumption of meat are compared. Not surprisingly, the countries with the lowest consumption of meat and, correspondingly, the highest consumption of carbohydrates, including fiber, have the highest rate of digestive cancers, particularly of the stomach.

Myth #6: Fiber offers protection from breast cancer.

Reality: A blatant, preposterous lie. According to the recent massive study jointly conducted by the U.S. Center for Disease Control and Prevention, the Ministry of Health of Mexico, and the American Institute for Cancer Research, it’s the opposite: women with the highest consumption of carbohydrates, and, correspondingly, of fiber, had the highest rates of breast cancer:

Carbohydrates and the Risk of Breast Cancer among Mexican Women

“In this population, a high percentage of calories from carbohydrate, but not from fat, was associated with increased breast cancer risk.”

Isabelle Romieu, et al; Cancer, Epidemiology, Biomarkers & Prevention; 2004 13: 1283–1289. [link]

Although this study has singled out carbohydrates as the culprit behind various cancers, where there’s smoke, there’s also fire: carbs and fiber are as inseparable as Siamese twins, as I have already explained in Myth #1.

Myth #7: Fiber lowers blood cholesterol levels, triglycerides, and prevents heart disease.

The myths about fiber’s role in coronary heart disease (CHD) and the management of elevated cholesterol have their roots in some dubious research, which culminated in “reduced mineral absorption and myriad of gastrointestinal disturbances” after the study participants were given supplements containing a mixture of guar gum, pectin, soy fiber, pea fiber, and corn bran along with a low-fat and reduced cholesterol diet.

The total reduction of LDL cholesterol after 15 weeks was from “7% to 8%”. As any cardiologist will tell you, the reduction of “bad” cholesterol from, let’s say, 180 to 166 mg/dL (-8%) is completely meaningless. Besides, if you cause someone to have a “myriad of gastrointestinal disturbances” in the process, that person is more likely to die prematurely from malnutrition and cancer than of stroke or heart attack.

Even then, this marginal reduction of cholesterol had little to do with fiber, and everything to do with the reduction of dietary fats. LDL cholesterol happens to be a major precursor to bile. The moment a person is placed on a low-fat diet, their cholesterol level drops because their liver no longer needs to produce as much bile.

In addition, intestinal inflammation caused by soluble fiber blocks the ability of bile components to get absorbed back into the bloodstream, further lowering the cholesterol level. This is as basic as the physiology of nutrition gets, and it makes the whole claim of a fiber-cholesterol connection a deliberate con.

There is another dimension to the con used to “prove” fiber‘s role in reducing cholesterol. Most of the studies on fiber’s cholesterol-lowering effect—particularly psyllium—used The American Heart Association’s (AHA) Step 1 diet.

The Step 1 diet is high in carbohydrates and low in fat by design, with less than 10% of total energy derived from saturated fat. During clinical studies among people using the Step 1 diet without added fiber, their total cholesterol fell by 8%, LDL cholesterol fell by 6%, and HDL cholesterol fell by 16%.

In other words, the Step 1 diet on its own, without any extra fiber and/or digestive side effects, demonstrates an almost identical drop in cholesterol as with added fiber. In legalese, this particular “coincidence” is called fraud, plain and simple.

So one fraud more, one fraud less…what‘s the worry, if my cholesterol goes down?

Well, there is a legitimate worry, at least, according to this respected source:

Problem with American Heart Association “Step 1? diet

“Although the AHA Step 1 diet decreased total and LDL cholesterol levels in this group of women, it decreased HDL cholesterol by an even greater proportion. In women, a low HDL cholesterol concentration is a stronger independent predictor of cardiovascular disease risk than is elevated total cholesterol or LDL cholesterol. Therefore, women who follow AHA guidelines for lowering their serum cholesterol may actually be increasing their risk of heart disease”

Alan R. Gaby, M.D. Townsend Letter for Doctors and Patients [link]

Amazingly, back in 2001, the AHA replaced the Step 1 diet with the Step II, TLC, and ATP III diets [link], which are even more restrictive in terms of fat, and even more permissive in terms of carbohydrates.

And don’t get me started on triglycerides… First, nothing raises triglycerides as profoundly as a high-fiber diet does, because, paraphrasing the smoke-fire cliché, where there’s fiber, there’re carbohydrates, usually eight to ten times as much.

This fact—the more fiber you consume, particularly from natural sources, the higher your level of triglycerides from carbohydrates intake—has been dodging Dr. Dean Ornish [link] one of the most prominent proponents of a high-carb/high-fiber diet.

Second, once inside the colon, fiber itself gets fermented by intestinal bacteria. Among the byproducts of bacterial fermentation are short-chain fatty acids—butyrate, acetate, and propionate. Most of these fatty acids get assimilated directly into the bloodstream to provide energy.

According to the Dietary Reference Intakes manual “current data indicate that the [energy] yield is in the range of 1.5 to 2.5” calories per each gram of consumed fiber [link]. If you aren’t starving, the absorbed fatty acids unused for energy get metabolized by the liver into triglycerides for further storage as body fat.

Granted, a few calories here, a few calories there, may not seem like a lot. Still, if you are consuming 30 to 40 grams of fiber daily plus whatever “hidden” carbohydrates you are ingesting unknowingly along with processed food, it all adds up to epidemics of obesity, diabetes, and heart disease.

Myth #8: Fiber satisfies hunger and reduces appetite.

Reality: When the scientists from the Human Nutrition Research Center on Aging at Tufts University decided to look at this dubious claim, here is what they have found out:

Fermentable and Nonfermentable Fiber Supplements Did Not Alter Hunger, Satiety or Body Weight in a Pilot Study of Men and Women Consuming Self-Selected Diets

“Despite the large total intakes of FF [fermentable fiber – ed.] and NFF [non-fermetable fiber – ed.] supplements, there were no significant changes in body weight or fat during consumption of either type of fiber, even among the subjects with higher BMI.”

The Journal of Nutrition [link]

And as you keep digging deeper, you soon realize that consuming too much fiber may actually contribute to obesity. Because fiber rapidly absorbs water and expands in the stomach up to five times its original size and weight, it indeed pacifies the appetite for a short while.

Unfortunately, while faking satiety, expanded fiber also stretches out the stomach‘s chamber, and each new fill-up requires progressively more and more fiber to accomplish the same trick. Lo and behold, in order to reduce its capacity and “speed up” satiety, surgeons suture the stretched-out stomachs of obese individuals or squeeze them with a bridle (LAP-BAND©). A complete opposite of what fiber does.

Myth #9: Fiber prevents gallstones and kidney stones.

Reality: I‘ve seen several observational studies that claim fiber can prevent gallstones. It isn‘t true. It‘s common knowledge that diabetes and obesity are consistently associated with higher risk for gallstones, and both of these conditions are the direct outcome of excessive consumption of carbohydrates, and correspondingly, of fiber. Beyond these few studies, there isn‘t a shred of physiological, anatomical, clinical, or nutritional evidence that connects gallstone formation with fiber consumption.

Here‘s an excerpt from Fiber Menace that sheds further light on the gallstone-fiber connection:

Fiber’s affect on the small intestine: Not welcome at any price

Gallstones are formed from concentrated bile salts when the outflow of bile from the gallbladder is blocked. […] before they can form, something else must first obstruct the biliary ducts. Just like with pancreatitis, that “something” is either inflammatory disease or obstruction caused by fiber.

Women (in the West) are affected by gallstones far more than men, because they are more likely to maintain a “healthy” diet, which nowadays means a diet that is low in fat and high in fiber. Since the gallbladder concentrates bile pending a fatty meal, no fat in the meal means no release of bile. The longer the concentrated bile remains in the gallbladder, the higher the chance for gallstones to form (from bile salts).

Fiber Menace, page 25 [link]

Just as with gallstones, kidney stones are also common among people who suffer from diabetes and obesity, because excessive consumption of carbohydrates increases the excretion of urine, changes its chemistry, and predisposes to kidney stones.

To investigate this myth further, I consulted PubMed, a service of the National Library of Medicine, which is the most thorough compendium of medical research. I reviewed eighty-one articles published between 1972 and 2005 (the year I was researching my book) that mention the words “fiber” and “kidney stones”. Not a single one of them connected kidney stones to fiber consumption, while several specifically pointed out that an increased consumption of carbohydrates is one of the major contributing factors.

One article suggested that a diet free of digestible carbs, but containing fiber, makes urine composition less stones-prone. You don‘t have to be Dr. Watson to deduce that fiber—an indigestible substance—can‘t materially affect urine chemistry, because what can‘t get digested also can‘t reach the kidneys. Besides, it wasn’t the presence of fiber that did the “trick,” for those investigators, but the reduction in digestible carbohydrates.

Myth #10: Fiber prevents diverticular disease.

For a while, it was difficult to disprove this absurdity by appealing to common sense. So I devoted a whole chapter in Fiber Menace to explaining why fiber CAUSES diverticular disease. Thank God, I am no longer alone in this thinking:

Fiber Not Protective Against Diverticulosis

Contrary to popular medical wisdom, following a high-fiber diet has no protective effect against developing asymptomatic diverticulosis, according to a colonoscopy-based study presented at the 2011 Digestive Disease Week (DDW) meeting (abstract 275). In fact, the study showed that patients who ate more fiber actually had higher prevalence of the disease.

Gastroenterology and Endoscopy News, July 2011, Volume: 62:07 [link]

Fiber May Not Prevent Diverticular Disease

For decades, doctors have recommended high-fiber diets to patients at risk for developing the intestinal pouches, known as diverticula. The thinking has been that by keeping patients regular, a high-fiber diet can keep diverticula from forming. But the new study suggests the opposite may be true.

WebMD, January 23, 2012 [link]

A High-Fiber Diet Does Not Protect Against Asymptomatic Diverticulosis

A high-fiber diet and increased frequency of bowel movements are associated with greater, rather than lower, prevalence of diverticulosis. Hypotheses regarding risk factors for asymptomatic diverticulosis should be reconsidered.

Gastroenterology; Volume 142, Issue 2, Pages 266-272.e1, Feb. 2012 [link]

The only problem with all of the above research is that it may take another six to eight years to tell people what I was telling them eight years ago: if you wish to protect your gut from diverticular disease, keep fiber out of it.

Myth #11: Fiber is safe and effective for the treatment and prevention of diarrhea.

Reality: Actually, it’s the complete opposite—fiber, particularly soluble, is the most common cause of diarrhea in children and adults. That’s why it’s recommended as a laxative to begin with. The idea of fiber as a preventive treatment for diarrhea is one of the most preposterous and harmful fiber-related frauds.

Soluble fiber is widely present in fruits, vegetables, laxatives, and processed foods, such as yogurt, ice cream, sour cream, cream cheese, soy milk, non-dairy creamers, preserves, jellies, candies, cakes, snack bars, canned soups, frozen dinners, sauces, dressings, and endless others.

It’s always expertly concealed from scrutiny behind obscure names such as agar-agar, algae, alginate, ?-glucan, cellulose gum, carrageen, fructooligosaccharides, guaran, guar gum, hemicellulose, Irish moss, kelp, lignin, mucilage, pectin, oligofructose, polydextrose, polylos, resistant dextrin, resistant starch, red algae, and others.

These inexpensive industrial fillers are added as stabilizers and volumizers to practically all processed foods, because they hold water, maintain shape, and fake “fattiness.” Besides, they are cheaply bought by the ton, and are resold retail by the gram for immense profit.

Once inside the body, these fiber fillers remain indigestible, hold onto water just as tight, and prevent absorption. This property—the malabsorption of fluids—lies behind soluble fiber‘s laxative effect: under normal circumstances a very limited amount of fluids enter the large intestine. When their amount exceeds the colon’s holding capacity, you get hit with diarrhea.

In other words, the term “laxative” is just a euphemism for a “diarrheal” agent. If you overdose on a fiber laxative, you’ll end up with diarrhea. If you “overdose” on fiber from food, you’ll end up with exactly the same diarrhea. But since fiber in food can’t be measured as reliably as fiber in capsules, wafers, or powders, it’s much easier to “overdose” the latter fiber and cause severe diarrhea.

Besides, fiber is even more offensive than synthetic laxatives, because the byproducts of its fermentation cause intestinal inflammation, flatulence, bloating, and cramping—just as described in medical references:

Malabsorption Syndromes

Colonic bacteria ferment unabsorbed carbohydrates into CO2, methane, H2, and short-chain fatty acids (butyrate, propionate, acetate, and lactate). These fatty acids cause diarrhea. The gases cause abdominal distention and bloating.

Gastrointestinal Disorders; The Merck Manual of Diagnosis and Therapy [link]

The diarrheal effect of soluble fiber is particularly harmful for children, because their smaller intestines need lesser amounts to provoke diarrhea. According to the Centers for Disease Control and Prevention:

The Management of Acute Diarrhea in Children

…diarrhea remains one of the most common pediatric illnesses. Each year, children less than 5 years of age experience 20-35 million episodes of diarrhea, which result in 2-3.5 million doctor visits, greater than 200,000 hospitalizations, and 325-425 deaths.

Centers for Disease Control and Prevention [link]

These figures are from 1992, the latest statistic I could find. It must be much worse today because fiber is so much more prevalent. And if you analyze the most basic facts, you’ll understand immediately why this travesty is taking place. Consider this:

A single adult dose of Metamucil®—a popular fiber laxative made from psyllium seed husks—contains 2 g of soluble fiber in 6 capsules [link]. One apple, one orange, and one banana—not an unusual number of fruits a child may eat throughout the day—contain a total 4 g of soluble fiber, or an equivalent of 12 capsules of Metamucil for a much larger adult.

And that’s on top of all the juices, cereals, yogurts, ice creams, candies, cakes, and all other processed food consumed on the same day, all loaded with fiber as well. No wonder that “diarrhea remains one of the most common pediatric illnesses” in the United States, and there is an acute shortage of pediatricians nationwide.

Myth #12: Fiber relieves chronic constipation.

I left this myth for last because it is the most pervasive. For the same false reasons that people believe in the cleansing prowess of fiber, everyone and their uncle also believes that fiber relieves constipation.

Not quite true. According to the experts from the American College of Gastroenterology’s Functional Gastrointestinal Disorders Task Force, all legitimate clinical trials “…did not demonstrate a significant improvement in stool frequency or consistency when compared with placebo.” [link]

In plain English, it means fiber is no better at relieving constipation than a sugar pill. Indeed, how could it be, when fiber causes constipation in the first place! Again, I describe the exact reasons behind the fiber-constipation connection in Fiber Menace.

Even The Merck Manual of Diagnosis and Therapy, the very first book your doctor consults when needing up-to-date medical advice, has recently changed their tune regarding fiber, clearly the outcome of my work.

“Fiber supplementation is particularly effective in treating normal-transit constipation but is not very effective for slow-transit constipation or defecatory disorders” [link]

In plain English, it means the following: “Fiber supplements will catapult healthy people into a loo because of their laxative effect. But for anyone with a history of chronic constipation, they don’t work.”

Finally, consider the stern warnings, that accompany Metamucil, a fiber supplement made from psyllium:

Metamucil Warning

So not only do fiber supplements not work for most people with chronic constipation, but they may also make them ill. Probably not ill enough to kill their libido as Dr. Kellogg originally intended, but imagine enjoying sex with your partner while being bloated and flatulent courtesy of extra fiber in your morning cereals.

That doesn’t describe a health food, does it?

Learn More About Fiber Menace at

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  1. What about vegetables? You only looked at fiber being added to a diet via fruits, but in reality, vegetables are a lot healthier.

    1. I was also wondering why he decided to use fruit instead of veggies. Veggies have a lot more fiber unless you are talking about avocados which are a fruit.

      1. Aside from melons, fruits have more fiber than vegetables. and by veggie, i’m not talking legumes which trump both fruits & veggies. and yes the avocado fruit is high in fiber.

        1. One regular sized Hass (Mexican/California) avocado has about 9 grams of fiber. Most of it is Soluble fiber and lesser amounts of the roughage insoluble fiber. Whole Grains are extremely high in intestine scraping insoluble fiber. Large amounts of Insoluble fiber causes intestinal cramps, bloating, pain and abdominal heaviness. It strecthes out the stomach and makes you look 9 months pregnant. I think a little fiber depending on the size of your abdomen should determine how much you need on a daily basis. Another thing folks. You DO NOT need to have a bowel movement every single day. Although it’s comfortable to have at least one BM a day, it is not necessary.

    2. He is not saying to avoid fruits and vegetables, just don’t binge on them for various bogus CW reasons.

      “Please do note that if you are healthy, active, and normal weight, there is nothing wrong with consuming fruits and vegetables in moderation. The point of this section is to impress on you that it is NOT OK to binge on fruits to ingest recommended daily intake of fiber.”

    3. Agree. Would have been more clear if he had addressed veggies. I feel that with the amount of veggies I consume while eating paleo or primal, the total fiber does approach 25-30 gm…

      1. I doubt that… You may think that celery is high in fiber, right? Well one large stalk of celery has 1gm of fiber, so you would need to eat 30-40 large stalks of celery each day to reach that amount. And each large stalk has 1.17gm of sugar, so you would get 36-48gm of sugar. This is according to the USDA’s National Nutrient Database for Standard Reference
        Release 26.

        You must eat a huge amount of veggies…

        1. Celery? Why would you try that with celery? Cruciferous vegetables like broccoli, cauliflower, brussel sprouts or other high fiber and low carb vegetables. Half the “carbs” in a brussel sprout are fiber and 2/3 of the “carbs” in broccoli are fiber.

    4. I agree. That was his weakest argument because he used ten servings of fruit, which no one recommends. Ten leafy green vegetables would have proved this “myth” true.

      1. I had the same thought… However he did address this by saying:

        “The ratio of digestible carbohydrates (sugars) to fiber in vegetables, cereals, breads, beans, and legumes is, on average, similar to fruits. Thus, no matter how hard you try to mix’n’match, you’ll be getting harmed all the same.”

        Not sure the truth in that statement. Just thought I would point out that he did address this.

        1. “On average” maybe, but that is misleading– average greens with bread & beans & you remove some very crucial distinctions!

      2. It is a weak argument. On the other hand CW advises several servings of fruits and vegetables like they are interchangeable.

    5. And where is the differentiation between soluble and insoluble fiber? Soluble fiber is converted into medium chain triglycerides by gut bacteria which in turn reduces inflammation in the body once absorbed through the gut. Anyway, who in their right mind would binge on fruits for the sake of fiber? Just the amount of fructose would scare me away. The author is trying to kick a door open which is barely hanging on it’s hinges anyway.

      1. Exactly! Not only does he not differentiate between soluble and insoluble fiber or talk about the very different effect they have, he doesn’t mention “resistant starch” at all other than in one spot where it is mentioned as an industrial “filler” instead of a 3rd type of fiber, which it is… a prebiotic that feeds your gut bacteria just like soluble fiber. He talks about short-chain fatty acids, like butyrate as if it’s a bad thing but doesn’t mention it’s healthy effects, particularly for intestinal health and reducing the chance of colon cancer.

        In short, I think this article is complete garbage and I’m surprised to see such junk on Sisson’s site.

        1. This article is anything but junk. Fiber is very very overrated. I have been going to the bathroom less and less since eating a low fiber diet and feel better overall.

    6. he did address veggies. He said they have a similar ratio of fiber to sugar. Is he correct? Maybe not.

      1. Wow this has sparked great discussion. This post about fiber is contrary to conventional wisdom and I believe some studies. I don’t think that there is enough here to give a definitive answer to fiber being bad or good. It seems to raise questions which I think may be the point.

    7. Nida,

      …because most people prefer to consume fruits for taste, flavor, etc… To some extent, fiber-rich vegetables are even more harmful than fruits because, in addition to a similar sugar content, they may contain more fiber, particularly a soluble kind, which may be even more damaging for children and older adults because its ill effects starts showing themselves in the small intestine.

      1. Konstantin – I think the biggest issue is that you lump all fiber together which kind of negates the theory that gut microbes are beneficial and require prebiotics to feed them.

        Prebiotics are all fiber, they don’t get digested in the gut. The terms soluble and insoluble only refer to a fiber’s relationship with water, not whether it’s fermentable by gut microbes. Resistant Starch is non-soluble, yet fermentable, and a prebiotic. Sugar Alcohols are soluble fiber yet are not considered prebiotic in that they are favored by non-beneficial bacteria.

        You are using CW from the 70’s to make an argument against fiber. As you will see–the readers of this blog are very much in tune with which fibers they should avoid and which are very important–pay attention and learn!

        1. I am sorry for creating a wrong impression, but I don’t lump all sorts of fiber together. This post was about a completely different subject. I do discuss these differences at length in my book as well as on my site.

      2. One of the core tenets of Primal Blueprint is that our guts host a wide variety of microbes, some harmful some beneficial. With proper feeding (prebiotics) the good will outnumber the bad and great health will result.

        That you say beneficial microbes simply feed off of the colonic mucous membrane, and no thought needs to be given to support a healthy gut flora, shows me that you have not kept up with current research in gut microflora.

        I agree that adding ‘fiber’ is a futile effort, but focusing your eating in a way to get added prebiotics is paramount to health.

        The real problem here is terminology…’fiber’ is a meaningless term. ‘soluble and insoluble’ mean nothing. What needs to be discussed is ‘fermentable and non-fermentable’ and ‘prebiotic’ fibers–that’s all that matters…

    8. I’m with you there. I for one think this author’s post is quite weak. It’s also kind of easy to find one research article on any topic that contradicts the medical train of thought (not that there’s anything wrong with going against the grain). However, the intake for fiber being around 40g is a little high anyway and most people are probably fine with around 20-25g of fiber intake. Also, why just fruits? Throw in some kale and you’ll get some great fiber AND antioxidants. There’s also some pretty good research out there showing fiber DOES decrease hunger and help to keep cholesterol levels in check (yes I’m aware high cholesterol isn’t the problem but you still don’t want massive amounts of it floating around in your vasculature).

  2. Except for this… “a moderately active adult can utilize no more than about 200 grams of carbohydrates per day without encountering a scourge of the inevitable obesity, prediabetes, or diabetes.”

    That is just blatantly false.

    1. Yes. Beyond false. Perhaps we should call it the Carbohydrate Paradox for those that consume 200, even 300+ grams of carbs a day yet never become obese or come near to the point of pre-diabetes.

      1. Including those that don’t workout much. Maybe walk a fair amount, move throughout the day and engage in some strength twice a week. There are millions of us in the world.

      2. Do you also reject MDA’s generalized and simplified carb curve?

        1. “Reject” is not the right word. I do think it’s oversimplified and while it may work for some folks, it’s not going to work for others. Adding carbs may help you lose weight.

          Also, I dare someone to get fat on plain white potatoes. Or plain table sugar with absolutely nothing else.

        2. Cloudy – Nobody does. We used to think fat was evil. Now we don’t. Now we think sugar is evil. Yet it’s not. Not by a long shot.

    2. I agree, Brendan. I often eat more than 200 grams of carbs in a day. Yesterday, I ate 280 grams of carbs.! Those carbs came from plantain chips (114 g), hummus (80 g) and rice crackers (87 g). Rarely do I eat less than 100 grams of carbs in a day. And I’m very slim. I recently had my fasting blood sugar checked. It was 81.

    3. Agreed.

      As much as we hate to admit it, look at some vegans for pete’s sake! That guy DurianRiders (as much as I loathe him) is one skinny dude and does marathons, and eats 30 bananas a day – that’s 800+ grams of digestible carbs, with most of it being pure sugar.

      I regularly get 200 grams or more of carbs a day now. My health seems just fine.

      That one blogger Danny Roddy is a huge proponent of sugar, after being vegan for a year, then VLC paleo for two years. I think the overly-generalized gist of his message is that PUFA-consumption impairs glucose oxidation, which results in diabetes, bad health, etc.

      I did a quick write-up about this issue, which I point people to when talking about sugar and paleo –

      I’ve certainly come to question the fear of sugars

      1. I have as well. Thanks to Matt Stone and others like Danny Roddy and Ray Peat. And Emily from And a bunch of other folks I trust.

        1. Oh, thank you for the author writers. I’ll check them out. Ray Peat’s stuff is really interesting.

        2. Danny Roddy? He doesn’t think Ketosis has any benefits. How bout people with Grand Mal siezures having them go away completely on Ketosis? It has been in the medical journals for a long time. The guy talks in riddles wrapped up in smoke and mirrors. I’ll check out Emily and Mr. Ray Peat and see what they are up to…

        3. “And Emily from And a bunch of other folks I trust.”

          I once wrote a comment pointing out that the BP diet stated that women should consume a good deal of carbs at least twice a week. She didn’t let it go through because she just wanted to be right, regardless if she was wrong. I’m assuming she does that regularly.

          “In the end, everything is bad because no matter what we do, we are going to die. So, my view is that nothing is inherently unhealthy.”

          That’s literally one of the stupidest comments I’ve ever heard.

        4. @Nocona, he doesn’t deny the benefits of a ketogenic diet, but he also recognizes its negative effects.

        5. I think you should amend that statement that sugar isn’t bad to carbohydrates aren’t bad. Clearly sugar can devastate your health, the main distinction being that sugar is 50% fructose while starch breaks down to 100% glucose. We have hundreds of studies clearly demonstrating the dangers of fructose, if you doubt that then you have some serious reading to do.

      2. You should really read some of the hypotheses of Dr. Otto Warburg, if you haven’t already. He won the nobel prize in the 30’s for his research on cancer cell physiology…. basically that sugar feeds cancer cells.

        1. In the end, everything is bad because no matter what we do, we are going to die. So, my view is that nothing is inherently unhealthy. If you sit on your ass all day and barely move, then the sugar you consume is not being used so perhaps it will feed cancer cells. However, if you are standing all day, walking a lot, engaging in various movements, just simply active, then the sugar you consume is being put to use. It’s being used as energy and is getting stored in your muscles and other places.

          Sugar is good. Too much is bad. Kind of like how water is good. Too much is bad. Sunlight too. And sleep.

          Balance is the key. We all have to enjoy life!

        2. OK Toad, we are all gonna die. So you can die being a balanced sugar/carb addicted person.

        3. Well, as a fan of Danny Roddy’s blog, let me give you my response, which are quotes from him.

          “Otto Warburg found that the defining feature of cancer was the production of lactic acid in the presence of oxygen (aerobic glycolysis). Warburg believed that cancer cells had a “respiratory defect,” or some kind of injury to the mitochondria that caused them to use up very large quantities of glucose by fermentation, even though oxygen was present. Therefore cancer cells demonstrate a failure of the pasteur effect, which is the normal response of cells to restrain glycolysis in the presence of adequate oxygen…

          … A very low consumption of polyunsaturated fats increases mitochondrial respiration (Rafeal, et al., 1984)…”

          While starving the cancer cells of glucose would certainly work, that is not attacking the cause of the cancer, so it seems.

          If you want to read more, this is the post I got it from –

          The ball is your court, Erin and Nocona!

        4. Mark P, thanks for the info. Looking at your photo, it appears you are pretty young. I’ll say this again…guys like Mark S., myself and thousands of other athletes who were thin and are now older (50’s-60’s), totally burned out our systems by living on carbs for fuel. We feel 100’s of times better now burning fat for fuel. Look at all the Friday Success stories too. It is a scientific fact you would die very quickly without fat or protein. You can live a long and healthy life without carbs and there are no needs for carb at all in the human diet.

        5. Also Mark P. Go live with the Inuit from 100 years ago up in Alaska and then tell me how much you need carbs.

    4. As a recently diagnosed T2D, I found this statement suspect as well :/

  3. This article should be on the front page of every magazine/newspaper!

  4. Why for Myth 1, does the writer state that fiber should be obtained from ‘fresh fruits and vegetables’ – and then debunk that using nothing but fruit as an example, as if vegetables don’t count and people would need to gorge on fruit all day to get ‘enough’ fiber? Plenty of vegetables are high in fiber and low in carbs (if that’s what you’re going for anyway).

    Also, hunter-gatherer diets are generally considered to be very high in fiber – up to 100 grams per day ( which is a lot more than most people consume.

    While I think some of the claims surrounding fiber and other nutrients are a bit ridiculous, I’m not sure this article does the best job at debunking them.

    1. Exactly, would you clarify that please, Konstantin?

      First you said –
      “fiber, particularly soluble, is the most common cause of diarrhea in children and adults. That’s why it’s recommended as a laxative to begin with.”

      Then later –
      ” it means fiber is no better at relieving constipation than a sugar pill. Indeed, how could it be, when fiber causes constipation in the first place”

      Fiber is both laxative and a cause for constipation? Is it like soluble fibres are laxatives and insolube ones are constipators?

      1. >> Exactly, would you clarify that please, Konstantin?

        I cover this subject in depth on my site. I didn’t address it here simply because I had to stay on topic…

  5. My non-primal friend just had a lumpectomy. Despite my giving her info I got from cancer survivors here, she read the cw nonsense about cancer and now eats a lot more fiber, fruit, other carbs, and therefore sugar. I’ll pass this great blog along to her but I’m not holding my breath.

  6. I’ve found that two teaspoons of plain old whole psyllium husk stirred into a glass of water–not Metamucil–works well for IBS, so Myth #11 isn’t always a myth. This was recommended to me by a naturopathic doctor to use on an as-needed basis. I do not experience any of the side effects associated with commercial products like Metamucil.

    Eliminating most grains from my diet, particularly wheat products, helped considerably, but sometimes something (possibly certain foods, maybe stress) still sets off an episode of loose bowels. I normally eat a lot of veggies and a modest amount of fruit, but it doesn’t help with an IBS flare-up. Whole psyllium husk and probiotics are the only things that really calm everything down for me.

    1. Thank you for this information. I am having a terrible time with IBS – diarrhea and haven’t found anything that helps. I will try the psyllium husk and probiotics. What kind of probiotics do you use?

      1. I used to have IBS too. Dairy was the culprit. Try to skip dairy for a month and see if it helps.

      2. I have found probiotics to be helpful with IBS too and the only kind that work for me are the kind found in the refrigerated section of the market (I buy mine at Whole Foods). I think I’ll give psyllium husk a shot though.

      3. I’ve had IBS since birth, but since switching to a paleo style diet a couple of years ago have found it’s about 85-90% improved. I definitely recommend checking out the GAPS diet as well. Bone broth does amazing things to help IBS. Further, most people with IBS need to completely avoid psyllium fiber. It’s a horrible irritant! Better to cut out sugar, grains and dairy, and increase your fat intake. Fermented veggies are great for the gut as well.

        As for this article, I have to agree with the other commenters that it’s got a ton of problems. Vegetable fiber is not even addressed. And overall fiber is just painted as “bad”, when in reality it does have a place in a healthy diet. It’s just not a good idea to obsess over it or consider it a cure-all or the cause of all illness. Common sense, people! 🙂

        1. “…most people with IBS need to avoid psyllium fiber. It’s a horrible irritant…”

          No they don’t, and no it isn’t. It depends largely on the person since everyone is different. I would not recommend commercial products such as Metamucil since they usually contain additives and other ingredients.

        2. I think it definitely depends on your individual case of IBS. Psyllium powder (which Mark Sisson recommends over whole husks) can work very well because it’s a PREbiotic, giving your gut bacteria something to eat & thrive on. Probiotics alone are not always enough, but it really depends on the state of your gut in the first place.

        3. What do you guys think about healing laxative abuse through fibre? Four years of anorexia (down to a BMI of 10.75) followed by 6 years of bulimia (laxative abuse) has rendered my gut pretty much destroyed. Making a conscious (REALLY conscious) effort to heal naturally using supps like Aloe vera and therapies like colonics and massage over the past year has definitely helped a little, but most resources I consult (doctors included) suggest fibre supplements.
          And now, I am royally confused. Would love some input.

      4. Yolanda, right now I’m using Prodophilus probiotics by Progena. It’s a powder that you stir into water. VSL#3 probiotics probably work better but are more expensive. It comes as either a capsule or a sachet. Both types MUST be kept refrigerated. I think both of these are available from Amazon but not sure. Some drugstores carry VSL#3. Check their website.

        Whole Psyllium husks are inexpensive and are available at most health food stores. Don’t buy the powdered kind. It doesn’t dissolve worth a darn. The whiole psyllium husks stir easily into a glass of water. Follow the directions and drink a lot of water with it.

        Keep a diary of which foods set off your IBS episodes so you will know what to avoid. Most people with IBS have problems with beans and legumes, onions, too much fruit, and dairy products. I can’t take much supplemental magnesium either and try to get that mainly from my diet.

      5. > I am having a terrible time with IBS – diarrhea and haven’t found anything
        > that helps. I will try the psyllium husk and probiotics. What kind of probiotics
        > do you use?

        While you are having diarrhea, probiotics are pointless because they will not stick inside the large intestine, and if they do — they’ll only make it worth. Same with fiber. And what you have isn’t IBS (irritable bowel syndrome), but IBD (inflammatory bowel disease). You can only stop diarrhea for good by eliminating inflammation by using what I call “elementary diet.” I discuss this subject at length in the last two chapters of Fiber Menace.

    2. the studies show that supplemental fiber is no more effective than a palcebo.

  7. While I don’t think fiber is of great value I do think it has a purpose if for no other reason than we evolved eating more of it in the tougher fruits in vegetables that had not been bred yet into the sweet perfect orbs of today. I believe there is some value in the intestinal bulk and easing of sugar rushes and containment of nutrients. That’s a major reason that those with teeth should avoid juicing. Naturally they want to sell you cellulose because it must be damn near free to produce and it can’t really hurt anyone when it’s not even absorbed. I’d estimate the article is maybe 80% correct but I must say this is one of the few posting that I do not completely feel comfortable with. Maybe it’s because my “one sided argument” sense is tingling.

  8. OK, well, Mark, if that’s your mission — I didn’t realize that was your mission. But I don’t think this piece is up to the standard of the site generally. It reminds me of Gary Taubes’ followers arguing that exercise won’t help you lose weight and calories are irrelevant. You don’t need to just take the polar opposite of every mainstream opinion…

    1. Formal exercise won’t help you loose weight. And isn’t necessary for good health either. It will make you strong, feeling good etc. but hungry too – you will compensate for the lost energy eating that many more calories, that’s a given.

      1. Stick with the informal exercise: strolling, shrugs maybe? Of course nothing will help you “loose” weight…it’s “lose” Don’t loose your grip on grammar!

        1. I hate the Grammar police!

          The phonetics of English are so messed up that it is impossible to stick to grammar. The English grammar is almost like an irresponsible government – arbitrary rules and arbitrary exceptions to every rule.

          With just 26 letters available to make all sounds and rules allowing people to pronounce ‘ghoti’ as ‘fish’, there is no way people can always be sure about their grammar. It is as if like, English Grammarians will never go without a job as long as Writing exists because it is impossible to codify all English grammar rules in a computer program 😉

        2. That was not a grammar mistake. It was a spelling mistake, most likely a typological error. Grammar pertains to the structure of language.

  9. I really feel like this is a fairly imbalanced article, which is inconsistent with the usual MDA approach of considering both sides of the debate. It is unfortunate, because I really would like to have an article on this topic to send to a few ‘concerned’ family members who think I’m crazy for eating primal for the last three years.

    1. I am sorry that you feel that way. There is nothing positive about fiber that I can describe. The whole thing is a fraud. Besides, I don’t say anywhere — “don’t consume natural foods that may contain fiber.” My message is “don’t pig out on processed food fortified with bran” and don’t take fiber laxatives because they harm your digestive organs.

      1. I think your article was fantastic with one exception – fermentable fiber which produces butyric acid does have some tremendous health benefits. There are studies showing that butyric acid put IBS and crohn’s patients in remission, and oat bran was used in this study.

  10. So are there any benefits to fiber at all?
    I find it hard to believe that a “nutrient” as prevalent as fiber does nothing but harm our bodies. One would think mother nature is smarter than that.

    1. No benefits, zero, zilch… When consumed in excess (>10-15 g per day), fiber does nothing, but harm. The body can cope with minimal amounts of soluble fiber, it “ignores” insoluble, but if you consume either one in excess, you’ll eventually pay for it with chronic constipation, hemorrhoids, diverticular disease, irritable bowel syndrome, inflammatiry bowel disease, and, if you aren’t lucky, with colon cancer/

      1. Why not address those of us eating large amounts of cooked dark leafy greens and vegetables? I eat large amounts of cooked spinach, chard, cauliflower, etc… and these contain almost no carbs whatsoever, but are both extremely high in nutrition and fiber. I completely understand and agree with your thoughts about companies trying to push fiber on us through supplements, etc, but why do you not make a more concerted effort to distinguish between no/low-carb veggies (with high fiber) and high-carb/high fiber fluff? There is a 180 degree difference between the two, one being extremely beneficial and the other being, as you have pointed out, very harmful. Apart from a single sentence saying young fit people should eat veggies, nowhere else in your writing do you make it very clear that while, yes, fake fluff fiber sold in garbage cereal is bad, things such as dark leafy greens, and lowcarb veggies are extremely beneficial (which we don’t eat for the high amounts of fiber.. we eat them for the mass nutrition they provide, even if they are naturally loaded with fiber). I really sincerely think that if you addressed this issue better, you would reach people more effectively with your theory and have less people dubious and skeptical of your entire article. If you made that distinction more clear, I do think you would appear much less “controversial”, and therefore your point would be communicated much more successfully. Just my suggestion. I do agree with you on the “fake fiber” propaganda, but I think again, a distinction would do much more good for both your and the readers sake.

  11. “Does dietary fiber contain anything of nutritional value? No, it doesn’t. Zero vitamins… Zero minerals… Zero protein… Zero fat…”

    Except of course when your (healthy) gut bacteria metabolizes it into short chain fatty acids.

    1. +100

      I don’t agree with this article. Fiber is extremely important to gut health due to gut bacteria, and those short chain fatty acids are vital to the health and integrity of the gut lining. They aren’t just additional calories.

      1. I agree. I think the basic idea of ADDED fiber being unnecessary is correct, but this article goes way offtrack with the rest of the information.

  12. Love, love, love this article! I have found many of these things to be true through personal experience. I was diagnosed with IBS with constipation over 10 years ago and docs prescribed an increase in dietary fiber as well as laxatives and fiber based supplements. This made me feel sick with no relief from IBS. Veganism was my next desperate attempt which made me even sicker. It wasn’t until I found a paleo-based diet and cut out the absurd amount of fruit and veggies I was eating, did I start feeling better. Great article. Thanks for posting!!!

  13. Urg…I’m following the Practical Paleo guide for IBS which says to focus on soluble rather than insoluble fiber (sweet potato/squash instead of kale/strawberries). So are both kinds not so good for digestive health and bacterial balance? Hopefully MDA follows up with some recommendations?

    1. Soluble fibers or resistant starches CAN be very beneficial for IBS ask it works to feed your gut bacteria appropriately. It might not work for you, but it’s absolutely worth a shot. For me, squash is fine, but starchy tubers are not. I have IBS-C/D (predominantly C).

  14. It’s naive to think fibers do nothing in the body, they’re important for healthy gut bacteria, in particular the water soluble fibers seem to be feeding bacteria in the gut that are important for our health. Look for instance at the Akkermansia string
    if you’re interested.

  15. This guy posts on The Healthy Home Economist’s blog occassionally, and I often wonder about his claims. I’m not saying that people need fiber from grains, but I don’t believe for a second that vegetable consumption for most needs to be moderated. I doubt that even people following a primal/paleo diet are eating vegetables in excess.

    1. The author stated the daily recommendation for Fiber is 30 – 40 grams daily. The source of which could be fruits OR vegitables.

      IF you choose to only use fruits to get that fiber, then he stated you would need all those fruites listed to get to 30-40 grams a day. He did not mention vegitables…I wish he had, but his point was that since fiber was useless, in his opinion, that consuming all those fruits in a day also led to the increase of 143 grams of sugar.

      1. He listed the 30–40 gram recommendation as MYTH #1. He wasn’t agreeing with it.

  16. Aside from the serious debates here, on the lighter side – “Dr.” Kellogg, ugh, who knew, you just can’t make this stuff up! Truth is stranger than fiction.

    1. Honestly! I feel like the first part of this needs to go on “Wait, Wait, Don’t Tell Me”.

        1. It seems like the craziest, most unlikely stories are always the true ones on that show!

    2. There is the funniest series on Comedy Central called Drunk History- they did The Kellogg’s a week or so ago. A total scream!

      1. Absolutely! One of their best ones! (along with the Lewis and lark expedition.)

  17. Ok, I am pregnant (first trimester) and one of the awesome side effects of pregnancy (besides nausea and vomiting) is slowed digestion and constipation. If the answer ain’t fiber, then what is it? Because I can barely stand to eat anything that’s not beige (potatoes, nut butters, and sadly bread) much less be primal, so I am perplexed as to what to do. I have started adding some benefiber to my water in hopes it would help. If not that, then what?

      1. I second this. Magnesium citrate, at mealtimes or at bedtime. Start at 200 mg and add as needed.

    1. fermented foods and dairy, fruits and veggies in moderation. meat and eggs. pls pls skip the nut butters and bread. go check out chris kresser’s healthy baby code.

      1. Einstein. I’m guessing you’re a dude who’s never been pregnant? I dare you to put a fermented anything in front of a 10 weeks pregnant lady and get away without being covered in vomit. Thanks. I’m aware of Chris Kresser. He’s never been pregnant either, far as I know.

        1. As a woman who’s been pregnant, try pickles. I know it sounds cliche, but the vinegar might help settle your stomach, and it’s probably easier to swallow than straight vinegar water (plus, you get some nutrients from the pickles).

          Also, not all fermented foods are things like sauerkraut. Wikipedia has a big list of fermented foods ( ), and if you look through it, you’ll find a number of foods that you could easily forget are fermented, such as creme fraiche (a type of sour cream) and sour cream, kefir and yogurt, and tempeh and miso. You might be able to eat one or more of them without getting nauseated at their sight or smell.

          And, of course, all pregnancies are different, so YMMV.

    2. I am now in my last month of my second pregnancy. Before conception I was consuming 3-5cups of greens/day plus many other veggies and fruits and meat and a little dairy (mostly raw cheeses). As soon as I became preg I had a strong aversion to most of the foods I’d lived on and found it perplexing and difficult that all the good stuff made me sick. Finally I cut myself some slack and can really relate to only wanting starches and nut butters. I found when I started allowing myself to have a bit of starch I could tolerate some of the other things too. I used sweet potatoes as a middle ground and started making some paleo based muffin recipes with almond flour… I also found that adding more fruit is what ultimately got me back to being able to eat. I know it’s contrary to this article and many paleo followers restrict fruits (particularly high sugar fruits) but this is what worked for me. I also ate a lot of eggs and tolerared them quite well. Shifted my greens from more spinach, kale, arugula, chard base to mostly romaine and found that I could again tolerate salad in smaller amounts. I hope you are able to find a combo that works for you. For me by 14 weeks I could eat most everything but the darkest greens (unless they were cooked, cooked was fine) and my fav avocados. Now I’m working on incorporating more raw dark greens again and can eat my yummy avocados. It will get better… keep trying

      1. What kind of fruit did you eat, alongside the starches?

        Maybe your body was craving some glucose sans-excessive-fiber???

        1. When I was pregnant (with twins) I couldn’t keep anything down for the first four months. Eventually I got over the nausea & became very hungry, but the only true craving I ever had was for oranges. Seriously, once I could eat I couldn’t get enough of them! I’m surprised the boys didn’t come out orange! I have no idea if this had anything to do with fiber.

      2. Nothing wrong with cooking your greens and other veggies, especially if it gets you to eat more of them. I read somewhere that a *reasonable* amount of cooking (ie, not frying/over-heating or cooking for lengthy periods where you will be oxidizing the food) will only reduce some of the nutrients, by about 20%. At the same time what you are doing is a bit of pre-digesting with the cooking so the remaining 80% are more easily digested and bio-available. Fermenting of course is better if you can handle that but steaming or slow cooking, say in a stew, is not so bad.

    3. during my first pregnancy (i was gluten free but not primal) i took hemp protein – the one that had the most fiber. it can be found at a natural food store. it tasted like eating earth, but worked miracles on the constipation.

      after my first trimester of my second pregnancy (after the nausea passed ) i was mostly primal and didn’t have any problems with constipation.

  18. “Colonic Motility: Energy-rich meals with a high fat content increase motility [the rate of intestinal propulsion]; carbohydrates and proteins have no effect.”

    This must be why all-carnivorous diet eaters don’t have to worry about getting ANY fiber at all! It’s the FAT and not fiber that keeps them from getting constipated.

    I guess we really DON’T need vegetation after all, as long as our meat’s grass-fed…am I right here? Is the vegetation really only for variety?

    1. The Intuit would have been up a creek if vegetation weren’t optional. The premier (non-allergic) infant food after breastmilk is meat based formula. We are closer to pure carnivores than our Mothers might be comfortable with, but there it is. I think we are lucky that we can eat vegetable matter and extract both calories and nutrients from it, but a sub-optimal food source, in my mind at least.

    2. Plants provide many nutrients that are not readily available from meat especially potassium and magnesium.

      Carnivores have a totally different gut physiology and a totally different gut microbiota to humans. That is why they don’t get constipated.

      The human gut microbiota closely resembles that of other primates.

      Traditional Inuits suffered from constipation. They also plants whenever possible.

  19. While I appreciate having guest bloggers here, I find this fellow’s tone tiresome. I come to MDA for Mark’s balanced voice and observations, and this reminded me of those sensationalized websites that are trying to scare you into buying their product.
    I was reading this, and I know that Chris Kresser (also a voice of reason in these wild internets) has a lot of good reasons to eat soluble fiber.
    Anyway… I feel like there is good info here but it gets lost in the delivery and amongst extreme claims that may not be true.

  20. I don’t agree with the angle of this article. Am I the only one who is reading this as anti-veggie??

    The primary source of fiber should come from green, leafy veggies and hardly any of us are eating enough of them!! It should NOT primarily come from fruits which are loaded with sugar which can cause blood sugar spikes and crashes. And it should certainly not come from “supplements”.

    I’m a firm believer that you can hardly ever consume too much fiber from the consumption of green, leafy veggies (preferably locally and organically grown) and that it CAN do wonders for your body in cleaning out toxins and sludge and can also act as a powerful form of preventative health care. Fruit should only be consumed in moderation, and preferably only in the morning on an empty stomach (or paired with greens in a smoothie).

    Where people often run into problems with their systems “backing up” and bloating is from improper food pairings – to generalize the problem as stemming just from consumption of fiber is not accurate (how many of you knew that combining protein and starch in the same meal throws your digestive enzymes through a rollercoaster and inhibits the effectiveness of nutrient absorbtion?? Ever felt like you wanted to take a nap after eating steak and sweet potatos? that’s your body working really hard to digest. Or how many have ever eaten a piece of fruit an hour after a grilled chicken lunch and been more bloated than a whale?? It’s because the sugars from the fruit have already started to break down but can’t move through your system because your body is still working to digest the meat you ate an hour ago, in turn turning the fruit rancid and toxic) – a bottleneck effect.

    A general rule of thumb is keep your meals simple and always have the majority of your plate be green, and eat light to heavy.

    I consume at MINIMUM 6 cups of fresh leafy greens plus additional vegetables daily and don’t experience any of these mal effects. In fact, my health over the past year or so has been greatly enhanced since I’ve upped my intake of veggies and greens and paid more attention to food pairings. I no longer suffer from seasonal allergies, my body found its ideal bodyweight, I sleep better and have more energy, I’ve even quit coffee cold turkey.

    So before anyone uses this article as justification for skipping, or skimping, on the salads (I really hope nobody takes it this way), don’t be too quick to write veggies off. I am a big advocate for starting your day off with a green smoothie. A good recipe is one organic apple or 3/4 cup pineapple, juice of 1 lemon, 3-4 cups of spinach, 3-4 cups of kale, 1 cup filtered water. Blend on high and it should make around 4 8oz servings. Just give it a try for a couple weeks and notice what changes.

    1. “A general rule of thumb is keep your meals simple and always have the majority of your plate be green, and eat light to heavy.”

      LOL – then I’m screwed. Eating like a rabbit never really made me feel better.

      “I consume at MINIMUM 6 cups of fresh leafy greens plus additional vegetables daily and don’t experience any of these mal effects. In fact, my health over the past year or so has been greatly enhanced since I’ve upped my intake of veggies and greens and paid more attention to food pairings. I no longer suffer from seasonal allergies, my body found its ideal bodyweight, I sleep better and have more energy, I’ve even quit coffee cold turkey.”

      Sounds….great, I guess. Not eating food, that is.

      “So before anyone uses this article as justification for skipping, or skimping, on the salads (I really hope nobody takes it this way), don’t be too quick to write veggies off. I am a big advocate for starting your day off with a green smoothie.”

      Yeah, that’s how our ancestors ate – taking mass quantities of inedible vegetables, pounding them to paste (don’t forget the filtered water!), and drinking them. I think I’d rather eat an egg, in any form.

        1. I don’t think Mr. Sisson will be cutting out his Big Ass Salads anytime soon. He is not worried about too much fiber…

          1. BAS is here to stay! I’ll write a follow-up to this article next week to share my thoughts and answer some of the questions posed here. Stay tuned…

    2. Joanna, if you start young, it takes 20 to 30 years to develop fiber-related damages, depending on your genetics and degree of luck. That is what’s so scary about fiber, and this why its advocates are getting away with murder, literally…

      1. Hi Konstantin,

        I appreciate your reply!

        I’m having a hard time imagining the worst that would come from a diet abundant in a rotated variety of fresh, local organic greens – but I realize I still have a lot to learn. A diet filled with fiber supplements, starchy fiber and loads of fruit, sure, it’s a lot easier for me to understand why that would be advised against.

        I read The China Study, Green for Life, and Kimberly Snyder’s books about a year ago at this time (this was before I found Paleo) and these books made a pretty big impression on me as far as the benefits of a diet rich in fibrous green veggies. I made a point to hugely increase my intake around this time about a year ago and the results were remarkable – it was around this time that I also slowly gave up dairy and gluten as well, however, so no doubt those played pretty significant roles.

        I’m certainly open reading more about the adverse findings of a diet high in fiber and my curiosity is peaked. Where would you suggest would be a good starting point for me to learn more?

        I’m also curious to read Mr. Sisson’s follow-up to this article.


        1. Joanna, check out Denise Minger’s response to The China Study. It’s an eye opener.

    3. “green, leafy veggies … CAN do wonders for your body in cleaning out toxins and sludge”

      Sorry-what?! Toxins and sludge?! What on earth are you eating (or suggesting someone else is eating) that results in toxins and sludge?! Is there anything in the medical literature that identifies these toxins and sludge?! No offense intended, but this to me sounds like a vegetarian trying to make meat sound bad…

    4. That is not his point at all! you can eat vegetables and fruits. just don’t over eat them. And don’t add fiber. Fiber adds nothing to our health. Just because it happens to be included in fruits and vegetables doesn’t mean it’s needed. The human body can deal with both kinds of fiber. But not if you over eat it on a consistent basis.

    5. Thanks for your comment Joanna. I agree 100% that we should be eating a plant-based diet… WITH eggs, grassfed meat, fish, etc thrown into those large plates of cooked greens. One or the other leaves you too acid or alkaline, or yin or yang as TCM would view it. I also agree about food combinations. Separating sugars from proteins is definitely something I advocate for making yourself ideally healthy. If you are more concerned with taste and pleasure then keep doing what you’re doing, but the fact is that optimal nutrient absorbtion will come only with optimal digestion chemistry, and sugars and proteins need different environments. Just eat them separately, it’s not a huge deal.

  21. This is a very important subject, and anyone who takes extra fiber for bowel movement purposes should at least read into to what he has to say. That being said, there are many effects fiber has on the body that one should keep in mind before going no fiber.
    Soluble fiber feeds gut microbes.
    soluble fiber tends to decrease the glycemic effect of a meal.
    Soluble fiber slows digestion (especially when taken with fat), which is good for protein absorption in the stomach.
    Insoluble fiber speeds digestion, which ensures less time for meat to sit in your intestines.
    insoluble also drags soluble fiber down to the lower parts of the colon before being fully converted by the microbes which allows the fiber to feed microbes in parts of our intestines.

    If you have trouble with insoluble fiber, cooking it will make it a lot easier to digest. One’s aim is to have a Goldilocks zone of both soluble & insoluble fibers, without taking in extra just to mask a possible issue one has with their digestive process.

    1. Konstantin left out a key fact, that whole foods don’t “just” contain pure fiber in a vaccum. I used Psyllium husks & ground psyllium seeds for years in the 80s-90s when I was doing cleanses. Some people react allergically to it & so much export quality psyllium has lots of fertilizers, pesticides on it, from unscrupulous growers in India. It’s label states it can be an irritant. I now use & recommend oil seeds like organic chia, hemp & perilla (oil). When my intake of dietary fat is steady (I eat a lot of fat, even pre-Primal) my bowels are happy.

      Chia has both oil & fibre & I don’t eat too much of it. I eat very moderate amounts of fruit, 1 piece a day or somedays no fruit at all in a day. I eat BAS but not as big or daily like I used to. I’m eating veggies, both cooked and raw. Moderation, respect for each others’ uniqueness & everyone finding their own unique way to optimize diet & lifestyle, helping each other along the way.

    2. Soluble fiber feeds gut microbes.

      — “Microbes” don’t need any extra feed. They get all the feed they need from mucus in healthy people. Soluble fiber may help for commercial probiotics to multiply outside of the mucosal membrane, but innate flora don’t require extra feed.

      soluble fiber tends to decrease the glycemic effect of a meal.

      — It actually doesn’t unless you consume it in very large quantities, and the ensuing inflammation blocks the digestion of nutrients, and not just carbs.

      Soluble fiber slows digestion (especially when taken with fat), which is good for protein absorption in the stomach.

      — Not true. Also, nutrients don’t absorb in the stomach, only in the small intestine.

      — Insoluble fiber speeds digestion, which ensures less time for meat to sit in your intestines.

      — No it doesn’t.

      — insoluble also drags soluble fiber down to the lower parts of the colon before being fully converted by the microbes which allows the fiber to feed microbes in parts of our intestines.

      — See above.

      If you have trouble with insoluble fiber, cooking it will make it a lot easier to digest.

      — Cooking doesn’t alter the properties of fiber unless you burn it.

      1. Hello Konstantin, thanks for clearing up some of these beliefs. There’s mounds & mounds of info against your conclusions, so you have a big hill to climb, but someone’s got to do it. I’ve been reading about the dangers of insoluble fiber around the net, so it seems like it’s starting to come to the forefront. I plan on reading several articles from your site, so you may provide the info there …
        -does soluble fiber slow digestion? If so, would eating it with meat(protein) allow the protein to stay in the stomach longer allowing it to digest fully as in many unhealthy people it seems it’s common for protein to leave the stomach not fully digested?
        -Does cooking vegetables make them easier to digest? The premise being that cooking breaks down the fiber somehow so your body does not have to do it?
        -You already said this was not correct, but doesn’t insoluble fiber push food through the colon quicker than without? or is this just one of the many myths used to peddle more fiber
        thanks in advance,

  22. I agree the tone and overall message are not what I come to MDA to see. It’s one thing to challenge CW, but rants are not useful in that regard.

    He lost me on the first myth – it’s a poor argument that must rely on hyperbole for effect. Is the point that the USDA recommendation is too high? In that case, what is the right amount? Zero? If you ate an apple, and maybe some lettuce, spinach, carrots, peppers, tomato, etc (ie, a salad) then you’d get a pretty moderate fiber load along with a moderate carb load. What would be wrong with that?

  23. All I know is that I’ve continued to get great results from a tablespoon of oat bran and a tablespoon of wheat bran, both raw/unprocessed daily on top of my cup of oatmeal. That constitutes my only grains and it keeps me a “regular” guy and has for years. Something about that bran whistling through the colon scrubbing it clean. Horsehockey? Maybe so, but it works for me!

  24. Loved the classic warning label on the Metamucil…and people still take that stuff. CW-be gone with you!

  25. in regards to inulin, i thought it was one of those things people with IBS should avoid, because it can be hard to digest, causing gas/bloating, etc?

  26. Unacceptable. This sensationalist, one-sided piece undermines the other content on MDA.

  27. Interesting how closed minded some of the posters are, especially since the whole Primal movement is based on challenging the conventional wisdom of the SAD and Chronic Cardio. I guess once you know everything there is no room or tolerance for opposing viewpoints.

  28. Ha! Of course FIBER is not good for your sex life… It causes some bodily noises and functions that are just not sexy, lol!

  29. This fellow seems more than a little monomaniacal… but I admit it was frustrating in my pre-Celiac diagnosis days to be told repeatedly by docs that I should eat more fiber to prevent my belly pain. I was a near-vegetarian, whole food/whole grain freak back then. Had I eaten any more fiber I swear I would have exploded!

    So I can see how someone might over-react against that relentless, one-sided & unsubtle refrain. But now he seems just as dogmatic & unsubtle.

    1. Paleo-curious – I agree. The whole article comes off over the top, even if most of the information is true.

      1. If the information is in fact true (and I have no clue if it actually is), then the over the top feeling would be from the fact that no one has ever fought these long standing beliefs before. Almost like before the cholesterol myth was debunked. The fact that the biggest cash crops (grain & corn) are both high fiber, it’s no wonder the industry wants us to believe they’re healthy to eat in large quantities. Nutritional science strikes again!

  30. His writing style is a bit hard to take but I do think he has some good information on his website and in his book (this article seems like he took his website and book chopped bits here and there and stuck it together without the full arguments or scientific reasoning) By following his fiber (he says to shoot for 15 g in the book), probiotics, and water recommendations my husband and I have significantly improved the lingering digestive issues we still had after going primal. I know the article seems like he condemns all fiber but he doesn’t I think he was just trying to make a big point with his article that fiber is not the superfood CW makes it out to be. Fruits and vegetables are ok but don’t overdo it. You shouldn’t need to rely on fiber to have good bowel movements and that’s what I personally found I was doing before I read his book. There is such a thing as too much salad.

    I’m surprised by some of the shocked and angry comments. Use the abundance of information and different perspectives on MDA to select what works best for your own situation and move on!

    1. Hi Christian. My name is lucas, im from Argentina. Im very interested in starting monastyrsky recovery progra since i became so much dependent on fiber, im totally constipated and have IBS for almost my entire life. I need some advice on what to eat acoording to konstantin low fiber diet, some idea on what to have for breakfast lunch and dinner. What food did you eat when you started the diet???

      Thank you!!!

  31. Who focus entirely on fruit and not vegetables? I’ll put $ down that is how most primal folks are getting their fiber.

  32. Interesting article but my main focus is to eat/live better. Less processed crap = better living.

  33. Also, where are the links to any actual scientific data on the statements?

  34. Ok, I disagree with most of you. The point of the blog is that fiber is not the miracle cure all. IMHO, that was reasonably presented and documented.

    If you do well on BAS, great. Show me evidence that Grok had a daily BAS.

    From Mark’s Carbohydrate Curve: 150-300 grams/day – Steady, Insidious Weight Gain.

    Yes, I would like him to have distinguished between soluble and insoluble. He did say early in the blog that fruits and vegetables are fine in moderation. The blog didn’t come off as anti-veggie to me. I would point out, however, that there are many anti-veggie members of the forum. (I am not one of them.)

    1. Hmmm..anti-veggie in what sense? I do eat vegetables. I like them, they are tasty with animal products. 😉 I just don’t think they’re necessary if you eat fresh, grass-fed meat with bone broth and organ meat. They strike me as a secondary nutrition source, not a primary one. Thus, I, at least, tend to react negativity when I hear about them as a sort of holy grail of health.

      I agree that it wasn’t anti-veggie post, but I don’t see as particular persuasive either. I’ve *never* heard of fiber being used to treat diarrhea, ever. (Myth #12) My husband and I were struggling with a minor stomach bug last week and we deliberately skipped our normal vegetables and salads because of their known effects. That kind of inclusion tends to make me question the rest of the article.

      I don’t know…he could have taken out about 6 myths and it would have been more compelling in my mind.

    2. Thank you for this. I didn’t find this article to be hysterical or ranting. I too would have liked a distinction made between insoluble and soluble fiber, but this article had a narrower focus; he was discrediting various common myths about fiber. If he was emphatic in his tone, so what? He had good arguments as well as scientific sources to back them up.

  35. Yes this guest author must be a total “quack”, with his challenging conventional wisdom, and use of PubMed to make a point. I cannot believe Mark didn’t run a background check on this guy. Did he even read his biography, or look at his “crazy” site? (Sarcasm)

    Mark I appreciate all you and your team do.

  36. I have personal experience with Fiber Menace and applying it to my own body. I’ll try and keep it brief and coherent.

    I had poor digestive health since I was a kid and my diet was not helping. Half a year before I changed my diet I had terrible constipation. I went to a doctor and he prescribed fiber supplements. I tried and my stool eventually just became so big and dry that I couldn’t expel it one day and developed an anal fissure that had me bleeding for a few months after most bowel movements.

    After I found fat head, things improved but not completely. I was still bleeding occasionally. I then found Fiber Menace and it rang true to me. The bad types of fiber were preventing the healing process by continually opening the wound (stool was too big/hard still). At that point I did a few things he details, I cut out ALL fiber and bought probiotic supplements. The probiotics were improving my gut flora and lack of fiber gave my fissure time to heal.

    Eventually, I came to the conclusion that not all fiber is evil. I started introducing plant foods back in to my diet and I could tolerate small amounts, increasing over time. Certain foods actually made things better. Root vegies and fruits wouldn’t trigger anything but chocolate, wheat, legumes and the types of veggies like broccoli, cabbage and spinach would make things worse, the differences being the type of fiber!

    So I don’t agree with Mr Monastyrsky entirely but there’s something to it. I believe if your gut health is compromised, insoluble fiber is one of the worst things you can do to it. Changing your gut microbiome is the real reason why I healed long term, but I needed to remove fiber for a year or so to allow things to settle.

    1. When you stopped fiber to heal what supplements did you use to overcome hard stools ?

  37. Yes it is…to some extent. But there the similarity ends. Metamucil can also contain wheat flour, fructose, soy lecithin, ascorbic acid (preservative), sucrose, FD&C Yellow No. 6, plus a variety of other ingredients, any of which can aggravate IBS. Whole psyllium husks are completely natural and contain nothing else. Taken according to directions, it can be helpful for both IBS-D and IBS-C.

    1. This was intended to be a reply to a different comment. I don’t know why it appeared here.

  38. I agree with others who have said they don’t like the aggressive, tirading tone of this article. My biggest complaint about it, though, is that it implies — DESPITE the disclaimer that normal people don’t need to restrict veggies — that vegetables are somehow not good for you, or not important in the diet. But I just don’t see this played out in reality. Obviously Kellogg was a nut, but it is a false choice that either we embrace him or reject the whole idea of fiber as having any nutritional value whatsoever. The author clearly has an axe to grind, and makes some perhaps valid points about the degree to which fiber has been wrongly touted as a fix for various health problems, but he does so at the expense of recognizing other aspects of the story — that fiber-containing foods have many health benefits. It’s just not that simple, and as others have remarked, I am glad to see that people don’t accept what seems like some oversimplification going on with this piece.

  39. I’m glad this got covered since it’s too popular to ignore, but “fiber is bad” is way too simplistic for the crowd on MDA. We know that there are all sorts of things in plant foods, not just carbs and fiber. Whole wheat, white rice, broccoli, and apples are all very different foods.

  40. Just read Kellogg’s bio on Wikepedia. Wow, “freak” doesn’t begin to describe it. But he and his brother (also a vegetarian) both lived to 91, which, considering how he lived, must’ve been a very long life indeed.

  41. Resistant Starch is a filler? Butyrate is bad for you? All forms of fiber are the same? WTF?

    Undercooked, or cooked and then cooled tubers – potatoes, cassava/tapioca root, yams, carrots, etc. These are all things that Grok would have eaten. These have what’s called “retrograded starch” which is a “resistant starch” which is a form of fiber and a prebiotic. Are we supposed to believe that this is not natural, and is not healthy?

    This article is garbage and Sisson should be ashamed to post it. Mark, this is an advertisement that you got paid for right? Please tell me yes, otherwise this makes no sense.

    1. In an earlier reply Mark already stated he’ll write a follow-up next week.

  42. Interesting article, I agree with a few of the reasonable posters as to the article sounding a little harsh against fiber. But a lot of anything is no good in my opinion.

  43. This is very one sided. Fiber is good, too much fiber? Bad. It’s the amount that counts and what else you’re eating with it, and also the type!

  44. I usually love reading the daily posts and comments from this site. But holy geeze, today a number of people commenting sound like evangelical followers of Grok. This post has done a great job of sparking debate within the primal circle; for that we should be thankful. I have much gratitude for the MDA team for bringing new perspectives to the board, we all need to reevaluate our perspectives once and a while ;).

  45. Pretty much all of the issues I had with this posting have been addressed, the tone is a bit alarmist, the fruit part, etc. But I wouldn’t go as far to say that I’m disappointed, particularly with Mark’s comment that he’d post a response. I think it’s good to get different takes once in a while, ruffling feathers is a good way to get the conversation going. I too come here because Mark’s evenhanded and reasonableness, I’ve noticed that some later postings take a slightly different position in the light of new research than his older postings on the same topic, and that proved to me that his message is based on science and not a set in stone opinion. Anyway, looking forward to the follow-up Mark.

  46. how come strawberries, blueberries, avocado or other fruits werent used as examples of fiber vs. sugar content?
    they have a lot less sugar and so do veggies.
    Never thought of fiber content before so it is an interesting read

  47. Dear Mark, Thank you for continuing to question dogma in all it’s forms and so generously share your investigations. I ran across this article over the past couple days in a quest for information on a totally different topic and ordered the author’s book, Fiber Menace. I am looking forward to reading about his work in more depth. I truly believe that questioning my very well-intentioned doctors, reading far outside the MSM, and finding reliable sources to educate myself about living my healthiest life have saved me from continuing down a very unhappy and unknowingly self-destructive path. I admire you, trust you and truly thank you for your dedication to improving my life and the lives of so many others. In my case, I think the often overwhelming, but very fortunate, news is once you start to question, you can never stop. Thank you again. XO, Ann

  48. Not sure about that wacko taco guy and some others but maybe eat more nuts.

  49. Not sure about that wacko taco dude and some others. Maybe eat more nuts!

  50. I never did buy into the need to supplement your diet with any kind of added fiber products. My intuition has always been that these products can scrape and cause more harm than good. I eat plenty of vegetables and a little fruit, take some probiotics and enzymes, and my digestion and regularity is great. Again, as so many have commented, eating whole foods, a grain-free primal diet, will get the job done just fine, no need for harsh fiber supplements.

  51. A friend just pointed out that Mark did not write this article.

  52. My attention was lost with the quote:
    “a moderately active adult can utilize no more than about 200 grams of carbohydrates per day without encountering a scourge of the inevitable obesity, prediabetes, or diabetes.”

    That is a ridiculous assertion to make and one that requires seriously strong evidence.

    1. Ben, its not ridiculous, you’re just under informed. There are reams of research papers done on carbohydrate demand. google “glycogen demands of exercise” , “daily glycogen demand sedentary”. Observe those around you who don’t exercise and watch how easy it is for most people to get REALLY fat when consuming 200gms of carbs a day. If you’re not incredibly active then those carbs aren’t utilized and things happen. Just because you don’t know about it doesn’t make it false and no one needs to spoon feed you references. Dig deeper, this is basic stuff.

  53. You lost me at:
    “It‘s not surprising that so many Americans are suffering from the ravages of diabetes and obesity”
    As if those problems all spring from eating too much fruit and vegetables and not fast-food, fiber-less white flour and sugar in all forms.
    And that’s only the tip of the iceberg when it comes to this article, as many have previously pointed out, so I’ll leave my comment at that…
    Can’t wait to read Mark’s reply!

    1. Both. Once any food is consumed and digested, your blood has no idea about its original sourcing. All it will “see” is fats, proteins, and sugars. Fat foods are more offensive than fruits simply because you can eat more of them in a single sitting, and wash them down with soda and shake.

      1. I fail to see how fat is the offender here. Also if you “wash all your fats down with a soda and a shake”.. well thats not really the same thing as having a cup of strawberries for desert, is it? Typically if you eat to satiety with a lot of fat then you wont feel the need to wash it all down with a soda and a shake. The only people who do this are either really fat, in a fat gaining trajectory or someone who is just really hungry.

        Fat foods are more “offensive” in what regard? To gaining body fat? Again, its the carbs from the soda and shake, not the fat, that is throwing a wrench in things. Your logic is putting Fruit on one side and Fat combined with soda and shakes on the other. That doesnt make sense to me.

        Im arguing here from an experienced based model, not just something Ive read.

  54. I am SO glad to see the facts around Kellogg’s disgusting and bordeline psychotic mutilation of children being shown to a wider audience, since the motivation behind his promotion of cereals as a go-to morning food sprang directly from his sick ideologies.

    His life’s work was based on a pathological hatred of sexuality, and yet to this day the ideas he founded are a primary part of the sanctification of cereals as a product in their own right, rather than in bread to mop up real foods like butter or gravy, or as an ingredient in cakes or sauces.

    I’ve been trying to tell my overweight friends & colleagues who struggle with constant hunger while loading up on “healthy, filling” cereals about him for ages, because his story is an important part of debunking the wholegrains myth, and often getting weird looks that I should think such a “great” man was so evil, and now I thankfully have this link to send them!

  55. I live by the mantra ‘the devil is in the dose’ so I definitely agree with your argument about eating all that fruit – it wouldn’t we healthy to do so. But what about vegetables?

  56. Mark, I am hoping you will devote a whole post of your own to all this – I am pretty convinced by this myth-busting, but also curious where cooked veg have a place, curious about what scientists like Phinney and Volek might have to say about it… Thank you!

  57. Hey Mark!
    Just wanted to say you’re brilliant! Testing out this ridiculous information on your audience by having a guest post it- that way you can find out just how much BS your readers are willing to buy without having to take the fall!

  58. “…….. decline of libido and infertility are among the very first symptoms of malnutrition prevalent among ardent vegans.” ——————- That’s weird. About a month after switching to a strict vegan diet, my libido went through the roof and hasn’t slowed down since (going on 9 months now). Can’t speak to the fertility issue though.

    1. It depends on one’s age. Younger people may get “hornier” on vegan diets, but not because of fiber, but because they are pumped up with sugars and insulin…

  59. Natural vegetables don’t contain a lot of fiber unless you consume them in crazy amounts. I’ll give you a sampling:

    1. Green leaf lettuce — 1.3 grams of fiber per 100 grams;
    2. Boiled potatoes without skin — 1.4 grams of fiber per 100 grams;
    3. Cucumbers, peeled, raw — 0.7 g/100 g
    4. Row tomatoes, with skin — 1.2g/100 g
    5. Onions, raw — 1.7 g/100 g
    6. Cooked broccoli — 3.3 g /100 g
    7. Carrorts, raw — 2.8 g/100 g

    So, as you can see, even the foods that are considered fiber-heavy, such as broccoli or carrots, are pretty moderate. So if you eat almost 2 lbs of the above vegetables, you still will get only 12.4 grams of fiber.

    That’s why I don’t say anywhere that you shouldn’t eat vegetables, and I do prefer vegetables to fruits because they contain significantly less sugar.

    1. I think this was the post a lot of people wanted to see earlier. Thanks for clarifying.

  60. Isn’t the fiber in fruit and vegetables structured differently then added fiber (e.g. cereals)? Natural fiber in fruits and vegetables surrounds sugar, slowing its absorption into the bloodstream, while added fiber will just clear out the gut. There is a big difference between eating a piece of fruit and consuming a cereal with added fiber.

    1. There are two types of fiber. soluble and insoluble.

      Did you read the article?

    2. That is not true. Fiber is fiber, regardless of its source. That said, you’ll get more damage and faster from bran-fortified cereals simply because a single serving of cereals may contain more fiber than 5-6 fruits or vegetables.

  61. Kellogg was a nut. And infant circumcision is sexual assault and should be prosecuted. My body, my choice: No one elses.

  62. I read Fiber Menace some years and found some of the suggestions helpful and some questionable. I am 60 now and have been trying to achieve healthy regularity for most of my life with inconsistent results. I’ve tried high and low fiber regimes and with all the issues that can be named.

    So my 40 years of experiments has led me to – some fiber from non starchy veggies like broccoli, cauliflower, cabbage, brussel sprouts, plus various nuts like macadamia, and almonds, and plenty of fat especially animal fat. Adequate hydration is essential but diverting fluids to the bowel rather than the bladder requires some assistance and the magic agent for that is magnesium. The fat stimulates bile and more bile appears to lead to a trigger for stronger peristalsis. And it is that action that should be encouraged to propel food and waste materials through our digestive tract, not bulk and gravity.

    It takes some experimentation on dosage but this mineral in the correct amount, combined with the other listed components seems to give quite consistent and reliable results. You’ll need to experiment to discover optimum dosage, you’ll very quickly discover if you have overdone it 🙂

    You will get some from many whole foods but it doesn’t seem like enough for many people and especially on vlc and Atkins type regimes. Magnesium deficiency also results for many in severe muscle cramps, something mentioned in one of the Atkins books with the comment that it didn’t know why. I have had such cramps for decades and magnesium has resolved that completely.

    Very high dosage will likely result in explosive results, so go easy at the start. as your body becomes more accustomed to higher levels of magnesium you should find a high degree of consistent results. I have found around 1.5g/day of magnesium citrate works for me, taken half in the evening and half in the morning.

    It also seems that magnesium is involved in a large number of biochemical activities so this supplementation seems like an all round winner, and without any of the damaging and harmful affects of bran and other artificial forms of fiber.

    So magnesium, modest natural fiber that most likely Grog would have consumed, quality animal fat, and good hydration. That package seems to work well for me at least.

    I have experimented with pre and pro-biotics but that always felt like an unnatural process that shouldn’t be needed if we are consuming whole natural foods.

    1. If we’re consuming whole natural foods, then shouldn’t supplemental magnesium feel just as unnatural as pro/pre-biotics?

  63. Fiber Menace was one of the first books I read a few years ago, when I realized that everything I thought I knew about nutrition was wrong. Following Konstantin’s advice, along with daily Metamucil, I eliminated the gut pain I’d been experiencing most of my life (as I swung back and forth between diarrhea and constipation) and learned what it was like to be regular. I also said good-bye to volcanic heartburn within a few days and discovered more of the wherefore.

    I still eat veggies and enjoy fruit in moderation, but if I’m not that hungry and the veggies or salad don’t look as appetizing as the steak or pork chops on my plate, I don’t force myself to eat the former for the sake of the fiber.

    1. (Sorry! I hit the ‘submit button’ inadvertently.) I was going to say that Wheat Belly, while coming at it from a different perspective, is a good companion to Fiber Menace.

      The book has much more detail than this post and I’ve recommended it to friends since I first read it.

  64. I admit that fiber is way over rated, especially the kind of fiber CW usually touts – that from bread, psyllium, fruits, and bulking agents. However, this article came off almost as if the author was suggesting we go as low fiber as possible. Sorry, but that’s not ancestral diet style.

    The lack of comments about fiber from vegetables was noticeable. I eat green leafies a lot, and get about 20-30g fiber per day from them. My regularity is far better now than when I ate the SAD. I also feel fuller when I eat veggies. While we obviously shouldn’t treat fiber as a magic bullet, the “demonization” of it by this author seems quite unnecessary.

    Also, I wonder what types of fiber all these studies used? What lifestyles and preexisting conditions and medications did the subjects have? What about fluid intake and activity? Studies can be misinterpreted, as we all know. I’m not going to look up all these studies, but I’d bet the subjects aren’t Primal Beasts.

  65. I tend to agree with the general thrust of the article as I understand it. You don’t need to go out of your way to get fiber—just eat real food. Fortunately, TPB accomplishes that.

    That said, I think the author has not integrated a lot of research on the brain / gut connection and also resistant starch. RS in particular is quite interesting. Hundreds of studies going back 30 years.

    Some benefits:

    1. It’s starch, but it won’t raise your BG even with significant doses of say, 30g.
    2. It’s starch, but if consumed in conjunction with a rapidly digesting starch (like a baked potato) your BG spike will be greatly less.
    3. #2 carries over even to the next day, blunting BG spikes after meals (called the “second meal effect”).
    4. Even a dose of 30g won’t knock you out of ketosis.
    5. Not only does RS resist digestion so that it can get to your colon (and all the way down, where most cancers originate), but probiotic bacteria in a meal, supplement, stomach or small intestine can hitch a ride on the RS granules and be protected from getting killed off before getting to the colon where they belong.
    6. You don’t actually digest resistant starch (this is why it won’t raise your BG), your gut bacteria do and guess what the by-products are? Short chain fatty acids (saturated fat). This is what helps blunt the glucose spike of other foods and subsequent meals.

    I’ve had a number of both T1 and 2 diabetics report to me that since supplementing with some RS (very cheap), combined with eating foods known to contain RS cold (this greatly increases levels from when hot, which destroys RS), they have achieved much improved BG control and have been able to reduce insulin dosage.

    Anyway, I’ve been doing a series of posts on it and in fact, those post were mentioned and recommended by Chris Kresser in a recent podcast. For anyone interested, here’s a link to one of the last posts, which is a comprehensive list of foods that contain RS and quantities. There’s also links to all my previous posts, including a couple that list tons of research.

  66. Outstanding post! — a “slam dunk,” in fact.

    Thank you, Mark, and thank you, Mr. Monastyrsky.

  67. @Konstantin, I am open minded. In fact enough to give your opinion’s some thought and questions. So gut flora don’t need to be “fed” and can live on mucus? OK, I’ll bite. What part of the mucus? Is it the oligosaccharide carb’s in the glycoproteins of the mucus? If not, how is the mucus feeding the flora? And if this is THE major source of food for the flora wouldn’t that hurt the mucus’ primary task of protecting the mucus membrane and epithelium, lubricating the intestinal tract so food can pass? I presume this glycoprotein serves some purpose (water retention?) other than feeding flora. I’m all ears if you’d like to explain.

  68. i’m so confused!! all i know for certain is that if i skip my heaping teaspoon of psyllium powder with 16 oz of water one day, i probably won’t poop the next day, and even if i do it’ll be hard, big, and incomplete. i’ve dealt with constipation since i was a teenager (i’m 47 now). from my early 20s until about 2 years ago, i ate prunes everyday so that i’d poop everyday. i only switched from prunes to psyllium when i decided to lower my carb intake.

      1. Drink and eat good fat. That will lube the pipes. Half a cup of ghee or butter melted will do the trick along with magnesium supplementation

  69. I discovered Konstantin’s site and read every page on it, and his book as well. Yes, his tenets fly in the face of Common Wisdom, and ruffles many peoples’ feathers. But if you are interested, please read his site – even without buying his book, the site has every point covered in the book in detail.

    I went Paleo over two years ago, and discovered soon afterwards. Much of what he writes about made so much sense to me that I decided to change and refine my diet even further.

    As a middle-aged woman, pre-Primal, I experienced many of the issues Gutsense describes as originating in excess fiber. Going Primal helped some of those issues – a lot, but getting rid of the excess fiber and fiber-minded dietary habits and occasional supplements took me to complete digestive health.

    As we can see here, Konstantin’s balls-out, take-no-prisoners style of obliterating the Common Myths about fiber in our health industry can rub people the wrong way. He is not as refined and measured as Mark Sisson (who is?). But don’t throw out his ideas because his delivery hits you over the head. There is plenty of life-changing info on his site and in his book. I know many folks with chronic digestive issues that would be mostly healed by a combo of going Primal and lessening dietary fiber. It is a greatly needed revolution!

  70. chacotaco,

    700g total glycogen store can be ACCUMULATED quite easily. One could max out/fill up their muscle glycogen stores by eating 700gms of carbohydrate for 3 days OR they could eat 200gms a day for about 10 days and then their muscle glycogen would be full, at which point denovolipogenesis. your muscle doesnt “run out” of all of its glycogen stores until you use them and its easy to lose the ability to efficiently access stored muscle glycogen.

    clearly youre a vegan fruitarian and clearly you have never had experience with fat people losing a lot of weight on a high calorie/high fat diet im guessing. right?

    youre giving about half the message. when youre mainlining pixie sticks, candy and high sugar fruit then your body WILL preferentially use carbohydrate. when youre NOT eating those foods and instead are eating a high fat/ adequate carb diet you WONT preferentially burn carbohydrate, as a matter of fact you will beging to more efficiently use fat as an energy source. It also doesnt matter if you “store” dietary fat during a meal as long as you can later access the stored fat.

    you said “switching out your dietary fat for sugar, while holding total calories and protein equivalent, is a phenominal strategey for losing weight”. in my experience with about 50 dedicated clients this is not at all true. ive tried it. ive had other people try it. i have no emotional attatchment to a certain diet or exercise schema, i just use what works. your strategy above proved to be a great way for fatties to always stay hungry.

    exercise mitigates a LOT of things that might otherwise be “bad” in a nutrition plan. if you have fatties blasting fruit and not exercising it will probably never work unless they are really hungry or just get sick of eating a reduntant meal (potato diet).

    if some of “this” is incredibly difficult to read then perhaps you should study more through the lens of an open mind. it seems you are looking for models that fit your beliefs and using example of high energy kids (stark raving mad athletes lol) who happen to be gobbling up everything in sight, like pixie sticks, to validate what youre saying. I would be you dollars to dimes that those pixie stick, soda drinking, sugar main-lining running-machine monkeys you are referring to are also eating half a pizza and double cheeseburgers whenever the opportunity presents itself. Lean, athletic kids typically have ZERO injury state, ultra high readiness and preparation, growth hormones kicking like crazy, terriffic sleep/activity patterns and very bright outlooks. If they choose to eat some candy its probably not causal in making them lean..either is eating a bananna or an apple or a chunk of fatty meat.

    you probably came to the wrong place to preach fruitarianism but keep reading.

    side note: myself and and a small group of other athletes and wrestlers HAVE used a ketogenic and or very low carb/ HIGH fat diet during a 3-5month training block. the fatties got incredibly lean, retatined muscle mass and went back to being able to eat carbs wtihout piling the fat back on after the training block. The already lean athletes became leaner, retained or gained muscle mass and everyone had very high energy levels. Does that mean that wrestlers should not eat carbs? Of course it doesnt. It means the body is a pretty amazing thing. Ive tried fruiting it up and I felt like I had to brush my teeth 30 times a day and by the time I ate a decent amount of carbohydrate I had to always supplement my protein. I couldnt do it. Too much time spent eating.

  71. Human breast milk contains fiber, per definition, in the form of GOS. 100% for certain. GOS can also be manufactured from cow’s milk and is used in making infant formula and coma patient food.


    “Constipation is a common problem and its prevalence increases with age. Severe constipation requires treatment with laxatives, but nutritional therapy, especially increased dietary fibre intake, is recommended primarily for the prevention and treatment of mild constipation. One alternative may be the use of oligosaccharides, which act as soluble fibre and have a bifidogenic effect. Galacto-oligosaccharides (GOS) resembling oligosaccharides occurring naturally in human milk can be produced from lactose. Several clinical studies reviewed in this paper have shown that the use of GOS (5–15g per day) may relieve the symptoms of constipation in adults and elderly people. In infants, the supplementation of formula with a mixture of GOS and fructo-oligosaccharides can modulate bowel function and stool characters in the same direction as does breast-feeding. Gastrointestinal symptoms may occur as side-effects of oligosaccharides, but 12g GOS per day or less is usually well tolerated.”

  72. @ Chaco taco

    Who uses 700gms of carbohydrate daily? Answer: athletes doing an incredible amount of glycolitic work. Its difficult to even BE ABLE to have the preparedness to do that kind of work. This IS basic stuff that you are either overlooking or choosing to ignore.
    You need to read some more on simple exercise physiology. Normies, occasional exercisers and fat sedentary people do NOT utilize 700gms of carbohydrate daily–that is preposterous. Muscles are glycogen depots but they don’t “share” with blood sugar. Once your muscle “gas tanks” are full then spill over does occur. Hard working athletes rarely have full muscle glycogen so there is almost always room for more dietary carbohydrate and they don’t get fat from eating a lot of carbs. This isn’t the case with non athletes or people with wrecked metabolisms.

    Let me guess: you are not a former fatty and you probably do lots of weightlifting or other decent volumes of glycolitic work and or you’re young and have never been fat? Also consider that high intensity exercise utilizes lots of intramuscular fats regardless of macronutrient composition of your diet. High intensity exercise always burns fat. Don’t make the mistake of thinking its simply the diet influencing fat loss.

    Adequate (which means low in some cases and “high” in others) carbohydrate in coordination with your exercise/activity glycogen demand can let you lose/use a lot of body fat even in high calorie states, even with VERY little exercise. You can’t have fat desk jockies plowing fruit and pixie sticks and expect anything good to happen UNLESS they are under eating and hungry.

    Fatty meats and nuts cause type2 diabetes? Have you read anything other than fruitarian hype in the past ten years? Have you ever tried a high fat diet utilizing low poly intake?

    I’ve personally watched the evolution of a lot of really fat people over the course of 3mos to 3years and without fail the adequate carb (dictated by exercise glycogen demand), moderate protein (enough to maintain or gain lean muscle) and high fat intake are the only fatties who have kept the weight off. This same template works for athletes and normies alike: don’t consume more carbs then you need, moderate protein, high fat. No one is hungry. The fats become leaner and the already lean athletes begin to fuel off of fat more efficiently. I’m sorry but I’ve seen it too many times in high level athletes to discount it. If mainlining fruit gave these guys an edge then they would do it. If a fat person could sit on their butt all day and eat bananas and pixie sticks to lose weight then they would do it. The only time I see ultra high carb working is in already lean athletes with huge glycogen demands. Again I’m curious if you’ve exhausted other dietary strategies or if your just digging in to defend what you are currently doing. I have personally tried high fruit, high carb, lean protein and low fat. It doesn’t work in the long term because you can’t realistically endure the exercise demands of utilizing that much glycogen. I’ve also personally useda ketogenic diet for 5 mos. I’ve also used a more “paleo” approach akin to what mark is suggesting. They can all work. Knowing how and why they work really helps a lot. Also, I’ve never been fat. Always very lean. If I go low carb during a phase where my exercise demands a lot of glycogen then I’m going to feel terrible. You could point your finger at my low carb diet but what you need to see is the ultra high glycogen demand does not pair well with low carb intake. You have to view diet and activity simultaneously. Marks “insidious weight gain” carb intake could easily be too few carbs for a hard training athlete utilizing a lot of glycogen. It’s only insidious if its TOO MUCH/MORE THAN YOU’RE USING. I know mark talks about this but it seems to get lost.

    Sorry for the multiple posting. I was afraid my cussing in the reply to chacotaco was keeping my comments from posting.

    1. Keep ’em coming. Great stuff. Chocolate Taco does not know that we can live long healthy lives without carbs. But you would die so quick it’s not funny, without protein and fat. They are neccessary. Carbs are not.

    2. chacotaco,
      I re read what i posted and I should probably add (since it seems some people dont have the basic information..sorry i dont know of a more delicate way to put it) that once your muscle glycogen reserves are full then they dont get used by anything except glycogen demanding movements. Walking around and being relatively sedentary uses up hardly any muslce glycogen. If your blood sugar gets low then you can draw on your liver glycogen reserves but if that runs out then you simply get lethargic or light headed–you dont draw muscle glycogen from muscle to use as blood sugar/brain fuel; it only gets used for muscular activity and even then, only when the demand is present. Your body wants to use fat for most everything it does involving movement. Where you come up with people using 700gms of glycogen daily under even moderate amounts of exercise is just not correct. Yes, it is possible to STORE that kind of carbohydrate if you eat a high carb diet but to deplete 400gms of muscle glycogen DAILY takes an EXTREME amount of high powered, high-intensity work that most people can not generate or tolerate. There are all kinds of pitfalls that arise when your insulin levels are elevated but you cant access muscle glycogen for work demand (because youre not getting any exercise mitigated insulin sensitivity but rather blunting it by over eating carbs). Eating that much carbohydrate without the exercise demand is setting you up for disaster. Also consider that fructose can NOT be used for muscle glycogen replenishment but it can still fill up your liver glycogen..and when liver glycogen is full (from eating tons of fruit, sugar and pixie sticks) then nasty things can start to happen; your body can end up storing the extra carbs in triglyceride forms and give you another heap of fun on top of your insulin resistance. Read up on some of this stuff as its pretty interesting and might help you in your training when the day comes that you are unable to exercise at huge glycogen demand rates or get sick of eating pixie sticks like all the lean kids you see running around.

      1. correcting myself and elaborating:

        im not saying that eating high carb prevents athletes or those already lean and exercising from utilizing muscle glycogen but rather that eating high carb when their is no increased insulin sensitivity present (from a background of glycolitic exercise) is what can lead to the inablility of a fat person to be able to efficiently store and/or access muscle glycogen. i dont have the links on hand. i will try to look it up in one of my exercise phys books if youre really interested.

  73. Brad,

    1. “Sorry, it’s tough not to be rude to people”? Nothing excuses being rude or condescending! You can have your debate and get your questions answered without sounding like an entitled brat.

    2. I certainly thought it was obvious that Mark sold supplements too, that you’re not forced to buy anything, that it wasn’t a paid ad, and that it’s ridiculous to fault someone for providing supplements while happily reaping the rewards of another person’s supplement services…but that fact seemed to elude you which is why a few posters including myself felt compelled to alert you of this fact.

  74. TKM – I definitely agree. It makes the MDA experience unpleasant when it should be one of the happiest places on the internet for people like us!

  75. john, im enjoying this conversation but weare for sure hi-jacking! oh well.

    i cant reply to your post so i will reply here. i replied after the double dash —

    you said :
    ryry, Going to keep this shorter than intended, but simply saying… Carbohydrate vs Fat largely doesn’t matter. If you (meaning generically, not you in specific) have an issue handling carbohydrate, then there is a medical issue that needs attention paid to it. Another thing to remember is that living by the scale is a terrible way to measure health.

    –I dont agree with this at all. If you have an issue handling carbohydrate then you probably got it from eating too much carbohydrate vs your glycogen demand imo. Ive watched relatively lean people overeat on fat while eating adequate carbohydrate and they didnt get fat like people who simply ate tons of carbs. i guess i cant prove it but you probably cant prove what youre saying either. its observation and anecdotal; just like what im saying. here: excess carbs mess ya’ up and excess fat adds calories faster than anything. agree?–

    Carbohydrate consumption adds water weight to the body as it is stored into glycogen stores. You could gain as much as 5-15 lbs of water weight on a refeed day from water alone.
    –you wont gain 15lbs of “water weight” from 400gms of muscle glycogen and 200gms of liver glycogen unless youre very heavily muscled. youd have to dehydrate too. we cut weight all the time for grappling. the only people who will lose 15lbs from depleted glycogen stores are 250lbs+ and lean. yes you can lose a lot more than that by dehydrating combined with depleted glycogen stores. on low carbohydrate (which could be 300gms a day if youre workouts are demanding 500..) youll end up excreting a lot more sodium as you sweat and work those muscle glycogen stores down..ending up at lower weights.–

    Part of the problem comes from, “What is high fat?” “What is low-carb?” The SAD is pretty high in both of those, so what you’re essentially doing when going from SAD to Primal, is losing the fear of saturated fat, and thus going highER saturated fat, and since you’re ditching the grains, legumes, etc…, you end up lowER carbohydrate.
    –to me low carb is loweER than your glycogen demand. also, ever notice how people who have always exercised usually arent really fat unless they are absolutely destroying carbs/fat. i think we agree on that.
    personally i didnt have a fear of saturated fat. ive always eaten high fat and high carb and ive always been lean. im calling high fat over 200gms/day and relatively higher carbs (300+). primal doesnt mean LOW CARB. you can eat a very primal diet and still eat high carbs.–

    The point is, there is nothing wrong with carbohydrate. Your source is more important than the energy. Your body is always burning both fat and glucose simultaneously (just in different ratios, according to activity), so it’s not like your body just “forgets” how to do it unless, as said, there is a medical condition involved. Going too high in either of the two can cause a problem, just like going too low. Too low carbohydrate forces your body to find other means of creating glucose, either from the protein you eat, or from your muscle and organ tissues. This is a backup mode for starvation, this isn’t meant to be a long-term energy state. To low of a proper fat intake prevents the body from absorbing certain vitamins.
    –this is only a “problem” if your exercise demands more glycogen than you are eating. its not a problem for most people because most people dont exercise that much or if they do they dont do it for long because they end up getting hurt (tangent..) you can basically flip everything you just said about going too low on carbs and eating “too much fat and protein” to eating too many carbs and not enough fat. i think its very dependent on your actual energy demands. neither one of us know what “the most natural state” for humans is. Are you familiar with Peter Atia and thefatacademy? How about the work of Phiney and Volek and the art and science of low carb performance or the art and sciend of low carb living? they all have really great information you might be able to utilize.–

    Playing around in the 20-40% area for them is usually better than sticking to some set of numbers that were possibly pulled from thin air for Mark’s Carbohydrate Curve, as each body has a different set-point for that, and not paying attention to weight while in either testing ground.

    –percentages dont mean that much in the context of total amounts of calories. 20-40% on a 2,000calorie diet isnt much but its a whole lot more in the context of a 5,000k diet. mark didnt pull the numbers out of thin air. His area under the curve is where most people’s glycogen demand will fall given the style of training he is advocating.–

    The water-weight thing was likely the problem the really obese people had. When I was nearly 400 lbs, I was eating 4500+ calories on workout days (mostly from rice, potatoes, sugar, tons of vegetables, fruits and meat). My water weight ended up putting me over the edge into about 430 some days during the beginning, despite strength gains, and lower inches around the waist, going down to 350 lbs in a few months as my body adjusted. (Well, mostly me adjusting to the taste of vegetables. God they tasted terrible.) Provided appropriate sources, this should work for most people.
    –I have worked with a few people as big as you were (good job losing the fat and making great choices btw). Again, if you go back to my previous comments where i talked about exercise being responsible for a lot of the effects of your body transformation, youll see what i mean. I doubt you were exercising with the same high intensities as you worked your way from a normal weight to 400lbs..right? So just because you ditched fat and loaded up on carbs and eventually lost fat doesnt mean it was driven only or even mostly by the macros you selected. Ive had 2 close friends drop crazy levels of body fat (from over 400 to 250) both did it on low carb/high fat without maintaining drastically low calories. i think your body can adapt to just about anything given a chance. you can probably lose weight on the popcorn diet or the banana diet or whatever. im searching for optimal and i see optimal as diet and activity being addressed as one unit; not two distinct things. also optimal is something that doesnt require undue mental fortitude. ive seen a lot of people with very high body fat levels go through extreme exercise and diet routines only to have their metabolisms go to crap (thyroid issues usually) or inevitably revert to the old eating and activity habits that gained them the excess fat in the first place. high fat, adequate carb is EASY because youre not hungry. you can eat and eat and eat..til your full. it always magic lol (im being fecetious 😉

    i have personal experience both doing and observing others doing low fat/high carb or low carb/high fat and without hesitation i will say the higher fat is better for overweight people. i think you guys are creating a calorie deficit and the deficit is doing most of the work–i bet you were hungry and still probably are if your fat intake is low, or you still have to “watch your weight”. i know as soon as my former fatty friends start flirting with carbs then disaster strikes swift and hard. these guys REALLY dont like being hungry either and i think thats the biggest advantage of ADEQUATE carb/ high fat– you stay full. you might try experimenting with a high fat/low carb type diet and be astute in your planning by limiting glycogen demand in your exercise (this is what mark is doing with primal blue print). if youre doing a lot of lifting and exercise in glycolitic ranges then no, the low carb thing probably wont work well but you can do some pretty amazing things on very low carb/keto just like you can with other dietary strategies as long as you plan your activities and workouts accordingly.

    weare probably preaching to the converted with a lot of the things we are saying to each other.
    thanks for the conversation.

    ps. im still standing by my comments to choco about people utilizing 700gms of glycogen/day. yes, you can store that much–no, you dont typically use it everyday. im guessing choco or yourself probably end up burning off the excess, slowly accumulated fat (from overeating carbs), by building up to some crazy high intensity workouts which end up using lots of fat as well as carb and then your averages simply work out. Also, I was recently reading in ACSM’s Advanced Exercise Physiology those extra carbs that may “overflow” and get stored as intramuscular triglyceride may simply be replacing some of the up to 180gms of intramuscular triglyceride that can be used up in a single high intensity exercise bout. ..thats a lot of fat to replace to maintain performance and your body can do it in a myriad of ways.

    best exercise phys books in order (easy reading first) imo:

    Exercise Physiology for Health, Fitness, and Performance
    Plowman PhD, Sharon A.

    Exercise Physiology: Nutrition, Energy, and Human Performance (Point (Lippincott Williams & Wilkins))
    McArdle BS M.Ed PhD, William D.

    ACSM’s Advanced Exercise Physiology
    American College of Sports Medicine
    (awesome book but dont buy it unless you have a decent grasp of the information presented in the previous listings)

    –i wish all of these book had also used high fat and ketogenic models in their studies but i guess we will have to leave that up to phiney, volek and atia and our own experimenting.

    1. i said “–you wont gain 15lbs of “water weight” from 400gms of muscle glycogen and 200gms of liver glycogen unless youre very heavily muscled”..uh that doesnt make sense. what i meant was that unless you are very heavily muscled you probably wont store over 400gms of muscle glycogen. also the amount of liver glycogen you can store is increased on high carb intakes (makes sense).

      you can figure out how much weight youre able to lose by depleteing glycogen stores but remaining hydrated. for a well trained somebody you should be able to deplete muscle glycogen with a good full-body 2hr long workout. dont eat carbs for about 16 hours and your liver glycogen is gone. now, make sure you are fully hydrated. note your weight. then, go ahead and dehydrate and see where you end up.

      you can establish a glycogen maximum and “full water weight” by eating, say 500-700carbs a day for a few days while keeping glycolitic activity to a minimum. then, fully hydrate and note your weight. this will give you a “max” or full glycogen state that you can then start determining (by doing the above “cut”) where your glycogen stores are full and where they are empty.
      for a normal carb eater you dont need full glycogen for optimal, short term, performance but too low of muscle glycogen will decrease performance. Im talking short term. you may very well need a lot of stored glycogen to actually perform your workout(s).

      if you deplete the heck out of glycogen stores and then “carb load” you can increase storage but this is really only helpful for an event that demands the glycogen.

      1. The reason DNL is rare is because even after your glycogen stores are “full,” they’ll swell up to 200% capacity. When you consume vast numbers of carbohydrate, your metabolism rises to burn the excess off, glucose gets a very clear priority over fat. During exercise, your body doesn’t burn through all of it’s glycogen stores either, as it attempts to save some of it. This prevents more fat from being utilized by the body for energy (as per ratio, as it would then be kept low as it burns through it’s highly prized, primary fuel source). As it is, your liver depletes in about 8-12 hours alone, and it gets priority in the stuff, but that’s only if you haven’t eaten any carbohydrate, such as when you go to sleep, wake up, “skip breakfast” and then go on about your day. Even when you’re sitting, you’re not likely going to remain completely still, and moving your muscles, even with an empty liver, will burn off your glycogen stores as well. The only way to really be empty on glycogen is to either fast for a few days, or to be chronically low-carbohydrate and moderate amounts of protein.

        In any case, the point is, if we’re trying to mimic the diets of our ancestors, the low-carbohydrate aspect of this is not right, as our ancestors did eat various amounts of the stuff as well, depending on location. We’re meant to thrive on whatever natural foods we have available. It’s where the -gatherer part comes from. Many of our equatorial friends likely enjoyed these foods along with leaner animals than we might be used too. The further north (or south) from the equator you get, you have fatter animals and less plentiful vegetation. (This vegetation would have likely been less leafy-greens and more like cucumbers, potatoes, fruits, etc…)

        We’re adaptable, and clearly able to go anywhere in between. We’re all splitting hairs when it comes to macronutrient breakdown.

        1. Agreed, John.

          I get what you’re saying and its all strategy. I just don’t like the angle of ” it’s fat causing you to get fat”. Well, it IS the calories from fat but only because you’re preferentially utilizing the carbs and storing the fat. Don’t over eat carbs and the fat ceases to be a problem. If we preferentially become efficient at fueling off fat then we can store the carbs. When people eat freely of carbs they rarely get full. High carb works great when paired with high glycogen demand. Personally, I feel that mimicking our ancestors diet is really putting the cart before the horse. The non-stop, low intensity, high mobilty activity of our ancestors, paired with part time glycolitic (high intensity) demands is what we should be mimicking. Banging out a high intensity crossfit or glycogen demanding weightlifting session, and then sitting immobile on a chair is probably not what our ancestors did on a daily basis, year round. The perfect diet fulfills the demands of your energy requirements. Body comp goals are somewhat irrelevant as you never would have got fat in the first place if one lived like our ancestors. High carb, low fat generally only works (long term) in the context of a high glycogen DEMAND. People don’t like to ” work out” that much. Adequate carb means enough to fuel the demand. I can fuel my glycogen demand in ketosis via gluconeogenesis and other means but if my glycogen demand is high enough then its sure a lot simpler, more efficient and perhaps “healthier” to just eat some carbs. The inverse will prove true too: if your glycogen demand is such that it can be met through adequate (maybe 100 for one person and 300 for the next) carb intake and you’ll function better and have less oxidative stress via a higher fat diet then why force your body to use carbs? Again, in a very dynamic movement environment lots of strategies can work. I’m looking for the best strategy for said environment. Higher fat, lower carb is a very good answer for most people given our typical movement environments. It’s a lot easier to stick to a diet or implement a dietary change if there aren’t as many ” rules” to follow, the food tastes good and you actually get full. It’s a lot harder to say “move all day like our ancestors did”.

          I’m not arguing with you and I know you’re not arguing with me. There’s merrit in all of this for sure. Thanks again for sharing.

        2. @John,
          You comment “glucose gets a very clear priority over fat” is not true in all cases. Only sometimes. It applies when the rate of energy expenditure is high enough. Under a certain threshold, fat is preferentially burned. The reason is the body wants to conserve glycogen for emergencies (fight/flight) and high intensity bursts. Both fat and glygogen get burned usually – it’s never either/or – but one is often higher than the other. So doing things like walking burns more fat and sprinting burns more glycogen. Heavy weight lifting burns more glycogen. This is because the rate of needed energy exceeds the rate that fat can be oxidized and so the anaerobic process of using glycogen, which doesn’t require oxygen, takes place.

          If you think about it from the evolutionary perspective it makes sense. Use fat during hunting/tracking and still have glycogen reserved for the sprinting attack, or to run away from a predator that surprised you. If the glycogen all got used up first, and an emergency happened, you’d be dead meat.

        3. @Ryry, I mostly agree with you and you put it well. Except for the part about preferentially burning the carbs and storing the fat. I’m not sure it’s that simple. Also keep in mind that everything ingested is not necessarily metabolized. We don’t burn and store 100% of what we eat, either carbs or fat. That law of thermodynamics thing is a load of B.S. Our bodies are not a simple internal combustion engine.

        4. ryry, we burn both all of the time, however. We are already efficient at burning fat, save for a very minute few with a metabolic disorder. The ratios are always different depending on activity. but the only time obesity becomes a problem is during the process of overconsumption. There is no just storing fat for starvation, it’s always being utilized. Similarly to glucose, even without a supply of carbohydrate, as the body will create it’s own. We already burn fat at it’s own levels appropriately.

          As for fat making us fat, it’s true. But under proper calorie consumption, physical activity, stress levels, etc…, it’s not keeping us fat either. The only thing that will keep us fat, and continually larger, is a calorie surplus with more fat than our body is burning off.

          Brad, my comment was in regards to carbohydrate consumption enough to break through 100% of your normal glycogen reserves (which it will go up to about 200%). Let’s see you’ve eaten enough to store 150% of your glycogen reserves. Under this scenario, your body begins to prioritize glucose utilization over fat, even under situations where it would normally do otherwise. This process continues until enough of it has been burned off and then the body will switch back and forth as normal.

    2. @Ryry, your sept 5 long post… great! Do you have a MDA login account/username?

  76. Yeah something felt off about this article. It felt almost like sensationalism I guess.

    It started with the first attempted debunking. I’m quite certain you could reach that serving with leafy greens and still keep the sugars low.

  77. There were a lot of good points in this article, I have a tendency to agree that fiber alone is not as valuable as what comes along with the fiber. I don’t agree with the author’s position that fiber is totally devoid of nutrition because in nature fiber comes as part of the total package and may act as a “sustained release” mechanism for water and nutrition within the gut. In addition, fiber acts as a prebiotic, helping to promote the growth of important probiotic bacteria. That alone is of great value to the health of the body. Some of the compounds produced during the fermentation of fiber also provide benefit to the body. So, in a nutshell, I agree that taking spoonfuls of Metamucil is not likely to be beneficial, I also agree that eating 10 servings of fruit for the fiber it provides is also not recommended, equally so, we shouldn’t look to grains for fiber; however, based on the published research, fiber may deliver it’s benefits further down the line, post fermentation, in the growth of good bacteria, or in the delivery of nutrients and water that usually come with the fiber!

  78. I think there’s just a language barrier with Mr. Monastyrsky that is difficult to overcome, it shows with how this article is written.

  79. Hmmmm….there’s a lot I agree with here, but the statement “The ratio of digestible carbohydrates (sugars) to fiber in vegetables, cereals, breads, beans, and legumes is, on average, similar to fruits.”……Is totally false with respect to vegetables. And the idea that you can’t get 30 grams of fiber without consuming tons of carbs is also false.

    I have had IBS all my life and am obsessed with feeling optimal as a result. I’m a quantified-selfer. I weigh my food daily. Here are the results from an average day: 1 12 oz yellow onion, 10 oz green cabbage, 3 oz shredded romaine, 1 oz radish, 1 oz zucchini, 6 oz avocado, 1 oz green onion, 10 oz broccoli, 3 oz spinach, 1.7 oz almond butter….the rest is meat and oil so no fiber and no carbs..

    Totals: 96.4 grams of carbs, 38.4 grams of fiber…

    Math is science….so there’s the science disproving the statement above.

  80. This is an interesting article to find on a site called “marksdailyapple”. Am I to believe that apples are as terrible for me as… well, everything except for fatty meats if this guy is to be believed? The inference, then is that the information (or misinformation) on this site is bad for me. Sometimes conventional wisdom is wisdom. If people made tons of money agreeing with it, then I assure you that Mark would be on board. You guys know he endorsed a shake for P90X that had it’s share of artificial ingredients, right? Follow the money. This guy is a hack.

  81. Fiber is the one sticking point for me when it comes to eating Paleo. I feel great eating the fish, meats and fats. I feel like hell when I eat the vegetables, fruits and nuts. When I eat fiber, I get stopped up. Period. When I stop eating fiber, I’m fine. Oddly enough, I keep going back to fiber mainly because of peer pressure from my family and the odd looks I get when I say fiber isn’t good for me. I don’t want to hurt my family’s feelings when they bring sweet potato casserole or fresh veggies to family functions.

  82. Why not address those of us eating large amounts of cooked dark leafy greens and vegetables? I eat large amounts of cooked spinach, chard, cauliflower, etc… and these contain almost no carbs whatsoever, but are both extremely high in nutrition and fiber. I completely understand and agree with your thoughts about companies trying to push fiber on us through supplements, etc, but why do you not make a more concerted effort to distinguish between no/low-carb veggies (with high fiber) and high-carb/high fiber fluff? There is a 180 degree difference between the two, one being extremely beneficial and the other being, as you have pointed out, very harmful. Apart from a single sentence saying young fit people should eat veggies, nowhere else in your writing do you make it very clear that while, yes, fake fluff fiber sold in garbage cereal is bad, things such as dark leafy greens, and lowcarb veggies are extremely beneficial (which we don’t eat for the high amounts of fiber.. we eat them for the mass nutrition they provide, even if they are naturally loaded with fiber). I really sincerely think that if you addressed this issue better, you would reach people more effectively with your theory and have less people dubious and skeptical of your entire article. If you made that distinction more clear, I do think you would appear much less “controversial”, and therefore your point would be communicated much more successfully. Just my suggestion. I do agree with you on the “fake fiber” propaganda, but I think again, a distinction would do much more good for both your and the readers sake.

  83. Um, this information looks really really ridiculous. I don’t trust what you’re saying.

  84. Maybe a simplistic argument, but I was always led to believe that the human stomach, and if I remember correctly it’s in Konstantin’s book, is primarily for digesting protein and fat. If we were meant to digest fruit, veggies our stomachs would resemble those of a cow, which has 4 compartments to its stomach.

  85. Interesting article, I agree with a few of the reasonable posters as to the article sounding a little harsh against fiber. But a lot of anything is no good in my opinion.

  86. Potential applications in food fortification due to rising functional food demand globally will propel the insoluble dietary fibers market size. Rising dairy, bakery & breakfast cereals demand owing to changing diet patterns and increasing health consciousness has enhanced the product demand. Effective functions including water binding, thickening, gelling and fat replacing are among key factors supporting product adoption.
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