Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
19 May

A Metabolic Paradigm Shift, or Why Fat is the Preferred Fuel for Human Metabolism

There’s a good reason so many people (mostly the sugar-burners, whose disparate group includes fruitarians, veg*ans, HEDers, body-builders, most MDs, the USDA and virtually every RD program in the country) can’t seem to grasp why a lower carb, Primal approach to eating is a better choice for health and fitness: their fundamental paradigm – the core theory that underpins everything else in that belief system – is flawed. They remain slaves to the antiquated notion that glucose is the king of fuels, so they live their lives in a fear of running low. The truth is, fat is the preferred fuel of human metabolism and has been for most of human evolution. Under normal human circumstances, we actually require only minimal amounts of glucose, most or all of which can be supplied by the liver as needed on a daily basis. The simple SAD fact that carbs/glucose are so readily available and cheap today doesn’t mean that we should depend on them as a primary source of fuel or revere them so highly. In fact, it is this blind allegiance to the “Carb Paradigm” that has driven so many of us to experience the vast array of metabolic problems that threaten to overwhelm our health care system.

It boggles my mind that such a large segment of the so-called health and fitness community would continue to defend high carbohydrate diets with such tenacity. It should all be very obvious by now. The studies keep piling up indicating that carbohydrate intake is the major variable in determining body composition and that excess glucose from carbohydrate intake (especially from processed grains and sugars) is the primary culprit in obesity and in many disease processes. It follows logically that if you can limit carb intake to a range of which is absolutely necessary (and even up to 50 grams a day over) and make the difference up with tasty fats and protein, you can literally reprogram your genes back to the evolutionary-based factory setting you had at birth – the setting that offered you the opportunity to start life as a truly efficient fat-burning organism and to continue to do so for the rest of your life as long as you send the right signals to your genes. Becoming an efficient fat-burner is the major premise of the Primal Blueprint eating and exercise strategies.

But logic doesn’t rule when you are stuck in the Carb Paradigm, so I still see some misguided bloggers decrying the Primal Blueprint eating strategy as potentially harmful for its relatively low carb intake or stating that my advice to “generally keep carbs under 150 grams a day unless you’re an athlete” is ridiculous. How many more times do I have to overhear a trainer advising a still-portly client to “eat 5 or 6 small meals throughout the day, always with some carbs, so you keep your blood sugar up and don’t go into starvation mode.”? It’s time to stop this nonsense and reframe the current views of human metabolism to accurately reflect the two and a half million years of evolution that shaped the current human genome – a perfect DNA recipe that fully expects us from birth to function largely on fats.

It’s time for a Metabolic Paradigm Shift within the health and fitness world.

The Faulty Carb Paradigm “Logic” Goes Something Like This

The basic underlying assumption is that glucose is the preferred fuel of most cells; BUT, because we can’t store very much glucose (as glycogen in liver and muscles), we need to provide a continuous source of glucose in the form of exogenous carbohydrate (high carb meals) to keep the brain, blood, and certain organs humming along and the muscles primed for activity. AND, if we don’t feed ourselves enough carbohydrate every few hours, our blood sugar will drop and we’ll go into “starvation mode” and cannibalize our precious muscle tissue. AND any lack of regular glucose refilling (i.e. skipping a meal or fasting) will cause cortisol to rise, which will have additional deleterious effects. FURTHERMORE, an excess of glucose in the bloodstream is known to raise insulin and will predispose excess calories (from all sources) to be stored as fat. THEREFORE, we should also be doing a lot of moderate-to-heavy cardio or lifting activity most days to burn off this excess stored body fat. HOWEVER, if we want to be ready and able to exercise frequently and strenuously to burn off our stored fat, we need to eat lots of complex carbohydrates between workouts to refill our glycogen stores. And ULTIMATELY, the only way to lose weight is to restrict calories (calories in<calories out), BUT if you’re working out regularly, it’s almost impossible to maintain a calorie-restricted regimen and still be able to work out hard enough to burn appreciable calories. Sheesh.

Sure, there are exceptions, like the driven and genetically gifted types, who can train long hours, refuel on carbs and not add much body fat (hey, I was one). But unless you love to work out incessantly and have really lucky familial genes, the Carb Paradigm is an unsustainable and ridiculous literal and figurative treadmill, a self-fulfilling prophecy for most people who tend to gain weight steadily and insidiously over the years and wonder why. If you are one of the 60+% of the American population who is overweight, the above scenario plays itself out because you have spent your life programming your genes in the direction of being an effective sugar burner and, as a result, have become dependent on a fresh supply of sugar (carbs) every few hours. Naturally, in the presence of all that glucose, and provided you actually do some exercise, your genes will eventually get the signals to up-regulate the enzyme systems, pathways and receptors involved in sugar-burning and fat storage and they’ll down-regulate all those involved in accessing and burning fat for energy. Of course, that doesn’t make it right, but it sure makes it appear as if glucose is king. What makes it worse, if you don’t exercise, you head down the path to insulin resistance and/or obesity.

The Problem: The Basic Assumption of the Carb Paradigm is Wrong

Glucose is not the preferred fuel of muscle cells under normal human resting metabolic conditions or even under most normal human movement patterns (exercise). Fat is. Sure, given an unlimited supply of glucose and regular refilling of glycogen stores, skeletal muscle will burn through it during exercise the same way a fire burns through kindling when that’s all you have to offer. The body can shift carbohydrate oxidation to keep up with intake. But skeletal muscle can burn fat with great efficiency (and far less oxidative fallout) at relatively high outputs for very long bouts. Cardiac muscle actually prefers ketones, and the brain can run just fine (maybe even optimally) on a blend of ketones and minimal glucose.  Our survival as a species has depended on these evolutionary adaptations away from glucose dependency. Entire civilizations have existed for ages on what is practically a zero-carb diet. Think about this: there is actually no requirement for any “essential dietary carbohydrates” in human nutrition. It’s possible to live a very long and healthy life never consuming much – if any – in the way of carbs, provided you get adequate dietary protein and fat. The same can’t be said for going too long without protein or fat. Cut too far back on either of those macronutrients and you will eventually get sick and die.

The Evolutionary Model

Fat and protein were the dominant macronutrients (when food was even available) over the majority of our two-and-a-half million years as evolving humans. The lack of regular access to food and a scarcity of carbohydrates for much of this time necessitated that we adapt efficient pathways to readily store and access body fat for energy if we were to survive day-to-day and generation-to-generation. Our movement patterns were such that we never required large amounts of glucose or that we needed to store very much glycogen. It was predominantly fats, ketones and the minimal infusion of glucose via gluconeogenesis that got us here. Dietary carbs were insignificant. In fact, when you consider how ridiculously small the body’s glycogen reservoirs are, you understand that it would have been impossible for us to survive as a species if glucose were truly the “preferred” fuel. The liver, the main back-up glycogen/glucose storage facility for the brain and other glucose-burning organs, can only store about 100 grams of glycogen. Less than a day’s worth. Your muscles can only hold another 350-500 grams, barely enough to run for 90 minutes at a reasonable clip, and that glycogen isn’t even available to provide fuel for the brain. Meanwhile, we have a virtually unlimited storage capacity for fat (like 100,000 grams or close to a million calories on some people). The reason glycogen storage wasn’t necessary is because, between our copious fat storage capability, easy access to fats as fuel, gluconeogenesis and ketones, we just didn’t need much. Evolution tends not to reward structures or functions that take up unnecessary space or waste energy.

So How Much Glucose Do You Really Need?

Much less than most people assume. At any one time, the total amount of glucose dissolved in the bloodstream of a healthy non-diabetic is equivalent to only a teaspoon (maybe 5 grams). Much more than that is toxic; much less than that and you pass out. That’s not much range for a so-called “preferred” fuel, is it? Several studies have shown that under normal low MET conditions (at rest or low-to mid- levels of activity such as walking and easy work) the body only needs about 5 grams of glucose an hour. And that’s for people who aren’t yet fat-adapted or keto-adapted. The brain is the major consumer of glucose, needing maybe 120 grams a day in people who aren’t yet on a low carb eating program. Low carb eating reduces the brain’s glucose requirements considerably, and those who are very low carb (VLC) and keto-adapted may only require about 30 grams of glucose per day to fuel the brain (and little-to-none to fuel the muscles at <75% max efforts). Twenty of those grams can come from glycerol (a byproduct of fat metabolism) and the balance from gluconeogenesis in the liver (which can actually make up to a whopping 150 grams a day if you haven’t metabolically damaged it with NAFLD through fructose overdosing). Bottom line, unless you are a physical laborer or are training (exercising) hard on a daily basis, once you become fat-adapted, you probably don’t ever need to consume more than 150 grams of dietary carbs – and you can probably thrive on far less. Many PBers do very well (including working out) on 30-70 grams a day.

The Fat Paradigm

The Fat Paradigm, under which the human species has thrived quite effectively for two and a half million years, recognizes that human metabolism is pre-programmed by evolution to be primarily fat-based (the real preferred fuel). In other words, our genes expect us to function optimally when we consume fats and can easily access our stored fat. The Fat Paradigm acknowledges that the body is able to manufacture adequate glucose as needed. It acknowledges that most typical human movement patterns can be fueled almost entirely by fats and/or ketones (PDF) if need be, but can draw on glycogen when energy bursts are required (and which can then be replaced over time). It acknowledges that fat (and cholesterol) are not the proximate cause of heart disease. It acknowledges that fat cells are designed to release stored fatty acids as required, especially during times of scarcity or fasting. It allows for intermittent fasting as a means of accelerating fat loss without sacrificing muscle tissue. It increases insulin sensitivity, modulates energy and mood swings, and allows for a normal and healthy drop in hunger and cravings. There is a downside, however: you can’t train long and hard day-in and day-out in the fat paradigm.

Now then, having explained all this, please understand that I am not carb phobic. I actually permit more carbs in the Primal Blueprint than many other low carb eating strategies. I prefer to view carbs as the “elective” macronutrient, as a tool to use to manipulate your glycogen levels as needed. Low carb isn’t even the main objective of eating in the PB: eliminating grains, sugars and seed oils are the primary objective. Of course, when you get rid of that crap and naturally limit your carb intake to veggies, root tubers and a few fruits, you almost invariably decrease carbs to under 150 grams a day. And that emulates our ancestral dietary intake.

I came up with a simple Carbohydrate Curve a few years ago that offers a pretty concise picture of where most people ought to fall if they are seeking optimum health and energy, depending on their size, weight, sex, age, goals, etc. Now, many hundreds of thousands of user experiences later, I am finding that the Curve is pretty much spot on for a large segment of the population.

When I say generally that a chronic intake of over 150 grams of carbs can lead to insidious weight gain over a lifetime, I am factoring in the concept that many people are at the effect of a familial genetic predisposition to storing fat easily under the carb paradigm (the 60+% overweight). I am also factoring in the drop in metabolism that happens naturally with age, as well as the fact that PBers don’t NEED to purge and refill glycogen stores every day via exercise. Yes, there are some people (a small percentage of outliers) who might maintain pretty decent body composition at up to 300 grams a day on little exercise. I would bet that they also are selective about the carb sources and do a better job of controlling overall calories, so there’s little excess to store. For most of the population, that 150 mark remains a good average level for maintaining ideal body composition.

Well, that was a lot to digest today. You see where I’m going with this. I need your help in showing the health community that their basic assumptions are wrong and that they need to make a Metabolic Paradigm Shift. I’m sure there will be lots of specific questions, so bring  ‘em on and I’ll do a follow up post in a week or two.

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. I think this is dangerous. To write such and article with spiritual consepts and just play it on your way of eating as its the new jesus. This is just redicoulus. It harms the body, people and the planet. Do you really want to smell like dead animals? kill young animal babies so you can get their milk. Please share some real facts that has been published and supported of all this claims. Not just some paradigm bullshit shift that you claim. If its one thing that has increased around the world the last years is meat and dairy and animal products in total. The results, the world a sicker place. People doesnt have empati, their ego is bigger then the planet. They rape, kill, does whatever just to satisfie their ego and status.

    Karl wrote on May 23rd, 2011
    • “kill young animal babies so you can get their milk.”

      “People doesnt have empati”

      “They rape, kill, does whatever just to satisfie their ego and status.”

      What are you, 12?

      Check out some conspiracy theories by Jessie Ventura, you’re really gonna flip.

      Nobody wrote on May 23rd, 2011
    • There has also been a increase around the world in the last years (speak English much?) of corn, soy, wheat and rice products in total – so all the raping, killing and satisfying egos must be due to those things!?

      Luke wrote on June 2nd, 2011
  2. What are your thoughts on Ezekiel bread as an alternative to breads?

    Dan Gatta wrote on May 23rd, 2011
  3. Big agriculture is killing the planet whether it is to grow wheat or cows. There is an alternative but it requires actual education, not slogans and labels. Such as Allan Savory’s efforts to reclaim deserts with a return to a denser population of free grazing meat animals.
    http://www.greenuniversity.net/Ideas_to_Change_the_World/AllanSavory.htm

    Bill DeWitt wrote on May 23rd, 2011
  4. Sunny — I find it funny that you are telling people to read 80-10-10 when you haven’t even finished the book yet.

    http://www.30bananasaday.com/forum/topics/high-fat-low-carb-diet-paleo

    Maybe we should eat a shit load of fruit and end up like this kid…

    http://freetheanimal.com/2011/04/a-100-raw-vegan-success-story.html#comment-69893

    Or maybe we could eat 4000 calories of fruit a day and gain 60lbs in less than a year like one of your “peacekeepers” on 30bad did. The crazy thing is…instead of telling her to cut back, the cult members are congratulating her on her weight gain?

    If my wife gained 60lbs in a year I would throw her ass out. :)

    Issac wrote on May 23rd, 2011
  5. ..good thing we didn’t step in it….

    Daveman wrote on May 23rd, 2011
  6. Oh gosh! Was I ever troubled by some of the latest posts.

    You want to “right-size”

    Iluvatar wrote on May 23rd, 2011
    • Holy Cow? What did I do to screw that UP? Doh!

      But anyway, a healthy diet starts off w/ EATING UNPROCESSED FOODS!

      It is a major pain, and it takes a lot of time – but that is the first step – for you and your children.

      You do prep cooking on the weeekends – USING REAL (store bought) foods – and they you prep it.

      You DON’T JUST eat a veggie-only diet; & and you DON’T just a meat (& fat) only diet – YOU EAT THEM ALL!!!!

      It is a balance! A balance set forth from our primevil (sp?) heritage.

      Dudes! We ate meat & we ate vegetables!

      And the latter we ate RAW! (Enzymes)

      And the latter led to a healthy gut (along w/ a rad-hard ample supply of bacteria!)

      Which led to a healthy gut!

      Which led to a healthy immune system!

      And the rest led to healthy brain function (saturated fats), healthy bone & muscle development (fats as well as meat protein)

      So please check out HOW you are DOING IT before you make your disclaimers!

      HOW you eat your veggies, HOW you eat your meat – MATTERS (and ob btw, I HATE non-extinct dinosaurs called CHICKEN – yuk!) – I want meat from mammals – just like we used to eat about 4 million years ago – KAY?

      It is about eating a DNA sequence that closely resembles my OWN!

      best, Iluv

      Iluvatar wrote on May 23rd, 2011
  7. But I really love cheese..and bread

    Rob wrote on May 24th, 2011
  8. Most of us go through rough times trying out different diets and lifestyles. Most times we get disappointed when the promised healthy results doesn’t show up or when health degrades after years on a typical wondrous diet. I am no exeption. 2009 I and my family went LCHF – Low Carb High Fat (Sweden). And it was good,initially and especially for me with a history of dieting away even being a raw foodist.I thought that finally I can eat FAT, BUTTERS and CREAMS without guilt or fear.Suddenly I was more accepted by friends and familys. But that didn’t last long. And thank God for that…I only regret that i didn’t listen to that little, little vioce whispering to my logic much earlier but all in good time, right!? Well, I developed a tremendous thirst for juicy, ripe fruits(?)I became constipated, aching from a new kind of fibromyalgia (wow)all over my body, dandruff, slow minded/thinking and other weird reactions. But, what else to eat!? Fruits are dangerous, fats are dangerous, not this and that…total confusion and disappointment. ‘Til I onne day surfing around the Internet for SOMETHING, I hit Freelee’s vids. I recognized the message but never fully understood. Today, I follow the 80/10/10 almost 100% and can experience results already! But fruits are dangerous!? Hm – nope. I thrive on them, Freelee does and many many more – perhaps even LONG term. If so, I can only work for enlightning the world and ask of Gods blessig to do so. Live a little; is a very good saying. Yes, let’s live a LOT, eating whole fresh ripe products without blood, pus and suffering…Love and Peace, over and out ♥

    Lena Buhr wrote on May 24th, 2011
    • Interesting. I have been following LCHF for a little over 10 years now (back well before it got to be popular in Sweden), and I have not experienced any of the problems you described. I would suggest you post this to http://www.dietdoctor.com/ which is a blog run by Andreas Eenfeldt, MD, a Swedish doctor. I had the pleasure of meeting Dr. Eenfeldt on the 4th Annual Low-Carb Cruise.

      TXCHLInstructor wrote on May 24th, 2011
    • Lena, I’m glad you found something that works for you but hope that you supplement and please do keep track of your blood sugars.

      Looking over the 80/10/10 diet, I notice that most of the food is not available locally for 3/4 of the year in my area (probably even less in your region). My food is all grown locally, sustainably, organically while your’s was mostly flown in from monoculture farms cut out of the rainforest. I’ve seen the deer, rabits and birds coexisting with my food, while your food requires massive wildlife death to make way for tractors, trucks and airplanes. Mine requires 1/1000 the fuel as your food to transport it to my table.

      If you are ethnically Swedish, it is even less likely that you are adapted to a Fruitarian diet. Good luck, and God Bless, but seriously, check your A1c often.

      Bill DeWitt wrote on May 24th, 2011
  9. Very interesting read and enjoying all the comments. I have a HUGE hate for how almost every lunch bar / cafe / restaurant bases their meals around carbs, pads all their salads out with pasta, rice etc. and it’s soooo hard to buy decent protein when you’re out and about. Luckily I learned to cook and now take my own food with me everywhere. I just wish more food places would stop pandering to everyone’s ‘carb addictions’ as I love eating out but it’s so hard to find good low carb choices. I feel much better on high protein and looooove coconut and nuts, and train so much harder and feel better and lighter on a 50 – 100g carb per day diet. Thanks Mark for your honesty and explanations!

    Kat Millar wrote on May 24th, 2011
    • have cooler…for travel…
      we think along the same lines..
      I keep my carb load at the zero to 50 range…And never have any problems with lifting- moving- thinking- grokking…GROK ON>>>

      Daveman wrote on May 24th, 2011
    • It’s all about cost. Carbs are CHEAP food, and those restaurants are making money by feeding them to us. Adding a cup of pasta to a salad is far cheaper than adding a cup of chicken. It’s all about dollars and cents, and they could care less about our health.

      Ann wrote on June 6th, 2012
  10. Been Primal for a few months now. In general I feel great and I’ve lost a decent amount of fat, but I have to say it’s been a real challenge finding the right balance of carbs to both promote fat loss and at the same time prevent burn-out from exercising. I know carbs are not suppose to be necessary, and my workout routines are Primal, but I really do notice a positive difference when I consume things like sweet potatoes after workouts. I do not consider myself necessarily an athlete, but I do lift heavy things about three days a week and move around enough other days, so I would love to hear more on tips for balancing fat loss with exercise on a Primal diet.

    Matt wrote on May 24th, 2011
    • Remember that Primal cuts out grains, legumes and processed sugars.

      You can eat potatoes and fruit. Especially if you lift heavy things and need the glucose for your muscles…they recover much faster with a little help.

      I’ve read that only people that want to trim down to an unhealthy level of body fat do 3-4 days of low carb meals + work outs…followed by 1 day of high carb meals (rice, potatoes)…followed by 1 day of Fasting.

      This is supposed to bring your fat % way down…your blood sugar took a dumb after the high insulin meals of the high carb day and now if you don’t eat the day after that your body has to burn fat to produce normal blood sugar levels again.

      4 days low carb, 1 day high carb followed by 1 day fasting…rinse repeat. You can make it 5 days low carb if you’re counting weeks.

      The rest of us who don’t care about a 5 or 10% body fat can eat potatoes and still be way under the average SAD’er.

      Nobody wrote on May 24th, 2011
  11. Okay, how about this scenario:

    Take two people.

    Drop them in the woods, say, 200 miles from the nearest civilization.

    One is given a bag of corn starch.

    The other is given a gallon or more of any kind of fat you choose.

    Each must hike to civilization eating only their macronutrients. One can only eat fat, the other carbs.

    Which one do you think will make it first?

    My point being, carbs provide a better fuel source for metabolism than fat does.

    I would bet the house that the corn starch fed hiker gets out first.

    This is backed up by any elite level competitive athlete, anywhere. NONE eat a low carb diet. NONE.

    soahc wrote on May 24th, 2011
    • OK, three days later we find the cornstartch man less then halfway there, still trying to choke down a dry powder, but the animal fat, *ketoadapted* man simply emptied out the fat, used the bucket for water, and walked fasting three days until he reached civilization. A fat burning metabolism will not run out of energy (at any reasonable walking pace) until all fat stores are depleted. Sugar metabolisms run out every couple of hours or so.

      Bill DeWitt wrote on May 24th, 2011
      • No, my point is, a carb burner will be able to hike faster. Sure, the fat burner may be able to go longer without eating, but as long as the carbs are available, the carb burner will be able to hike faster.

        Corn starch is easily assimilated mixed with water.

        And, again, no elite athletes eat low carb. WHY IS THAT?

        soahc wrote on May 24th, 2011
      • Oh, I see your point. You say that since the corn starch will weight a lot, and the fat burner will not have to eat as often, the fat burner will be able to hike faster because they can just eat a bunch of fat then ditch the rest and keep hiking without food.

        It really depends on what kind of survival situation. Long term, ketosis may be a better state for survival in famine, however when the need for explosive activity arises, like fighting a mountain lion or sprinting, the carb burner would fare better.

        You’ll never see a Mongol wrestler on their traditional diet winning the UFC.

        soahc wrote on May 24th, 2011
    • “My point being, carbs provide a better fuel source for metabolism than fat does.

      I would bet the house that the corn starch fed hiker gets out first.

      This is backed up by any elite level competitive athlete, anywhere. NONE eat a low carb diet. NONE.”

      There is a difference between ideology and evidence. Unfortunately for you, the evidence is much more equivocal and indicates that a high-fat diet can indeed play a large part in preparing endurance athletes for competition. Specifically, in several studies there was no statistically significant difference in the performance of athletes using both HC and HF diets. Just for starters: http://home.trainingpeaks.com/articles/nutrition/fat-and-the-endurance-athlete.aspx

      There’s plenty more available if you use your webz foraging skills to expand your horizons beyond vegan sermons and echo chambers.

      Todd wrote on May 26th, 2011
    • “This is backed up by any elite level competitive athlete, anywhere. NONE eat a low carb diet. NONE.”

      REALLY?!

      How about world-class Swedish triathlete Jonas Colting? He is on the record as stating that a high-fat, low-carb nutritional approach has not only improved his health but also maximized his athletic performance in competitions. He has won the Ultraman World Championships in 2004 and then again in 2007 as well as high finishes in the Long Distance World Cup in 2001, 2004, and 2005.

      Also I do recall a female low-carb athlete at least placing )if not winning) a recent iron woman championship…

      Also – to your experiment, if already adapted to their diets (switching off carbs takes 2-4 weeks to detox) then the guy with the fat will win – PERIOD. He (or she) will even likely have fat left at the end (a gallon is a LOT of energy (fat is 9 kcals/g – compared to carbs being 4 kcals/gm) Meaning your carb person would have to carry DOUBLE the weight (assuming equal density of food calories) to have the same number of calories.

      However even if not adapted – your experiment is flawed. If they have enough energy with them – they both get there.

      Lastly – as has been suggested, if someone is already n fat burning mode, then they can EASILY dump the gallon of fat and just run unencumbered by any additional weight.

      A 75kg (165lbs) man with 10% body fat has 7.5kgs (16.5lbs) of fat to burn… if they have not been eating carbs, and hence switched into fat burning mode they can EASILY use their fat stores as energy.

      200 miles would require maximum 28,000 kcals (assuming 25yo, male, 5’11” running at 7.5 miles per hour for 30 hours (allowing for SOME rest – as 30X7.5 is more than 200 miles, so the kcals required is LESS than that)

      With 7,700 kcals for 1kg (2.2lbs) of fat, this 28000 kcals would burn 3.6kg (7.9lbs)

      Leaving 3.6kg body fat, which equates to 5.5% body fat remaining.

      If eating the carbs – they would need to CONSTANTLY stop and refuel, as their bod would not be able to easily access body fats…

      The reliance on carbs for these events is evident to ANYONE that has used a carb gel during a long race.

      Even for a marathon (42.2 km/26 miles), runners have to dose up on carbs from gels or drinks… so 200 miles would definitely require the same regular dosing.

      In competitive sports there is no doubt carbs give bursts of energy, which results in performance, but so do steroids, doesn’t mean it is good for you.

      Fact is NO ONE has done the proper trials to check who would win in your scenario.

      However this study did look at runners:

      http://sciencenewsmagazine.org/pages/pdfs/data/1996/149-18/14918-20.pdf

      Only issue is everyone is so indoctrinated into believing fats are bad, that “13 runners failed to comply fully with the third regimen, complain- ing that it was too fatty, even though they gained no weight”

      The third regime being “45 percent of calories” came from fats.

      Results are there:

      “At the end of the two fattier diets, the athletes increased the amount of time they could run at peak capacity by an average of 7 percent—or about 30 seconds. Overall endurance increased 14 per- cent, and exercise-induced muscle fatigue decreased. Moreover, the study found that runners who consumed the fattiest diet used their stored energy more efficiently than they did when on the lowest-fat diet.”

      May have been better if the morons worried about eating fats had complied, instead of believing the DOGMA that fats are bad.

      So let’s set it up, with a high carb and low carb athlete… still willing to bet your house?

      😉

      Luke wrote on June 2nd, 2011
  12. Actually they won’t have to eat any fat at all. If they are already ketoadapted, they can burn body fat as easily as dietary fat. Look on the first pages of this thread and find the youtube link to the hunter who ran down his prey over 8 hours with just water. Carb addicts can’t do that. As for your “Elite” athletes, the paradigm has not yet shifted, so of course most athletes follow the outdated carb loading advice. That’s called “Argument by Authority” and is a fallacy used when the facts are not sufficient to support the contention. I suspect that if someone points to an athlete who does eat low carb, you will shift the definition of “Elite” until it excludes that person.

    Bill DeWitt wrote on May 24th, 2011
    • No, if they are in ketosis, they will NOT be able to push as hard as the person burning carbs.

      Call it whatever you want, if the paradigm shifts and gymnasts, boxers, wrestlers, and sprinters start using fat as their primary fuel, I will eat my words.

      But they won’t. It will never happen. Look, don’t you think that if fat was a better fuel source, elite athletes would be using it by now? These are people that will go to no end improving their performance by any means. Of course they would have changed their diets away from carbs if fat is better.

      Put a 25lb sack of corn starch on my hikers back, and they will hike out faster than your ketosis hiker who carries NOTHING. All else being equal, both being people of average fitness.

      Again, I would put money on it.

      The burden of proof obviously rests on you, since no current athletes run on ketosis (unless they do and don’t talk about it).

      soahc wrote on May 24th, 2011
      • No current competitive athletes that is, IE the ones who win.

        THat includes sprinters and endurance athletes. If fat adaptation is so much better, why wouldn’t marathon runners on an olympic level do away with gatorade type drinks? After all, they make a living, many from poor countries, competing. Seems like they would make any adjustment in macronutrient ratios necessary, but still they carb load and drink sugary drinks and gels.

        soahc wrote on May 24th, 2011
        • carbohydrates serve well as a fuel when you are doing high intensity activity because glycogen oxidizes as fast as you take in oxygen, and that’s what you want when you are doing high intensity heavy breathing activity. and the body has limited stores, hence why athletes refuel often.

          but day to day, a diet that is high fat, low to moderate carbs increases stock performance.

          So yeah, use carbs for high output activity if you want.

          George wrote on October 22nd, 2011
      • I could ask you to prove that none do, since there are some on this board who do. But no one denies that carbs are a faster burning fuel. But you have switched from a 200 mile hike, to fighting mountain lions to sprinting. In the rare instance that you have to fight a mountain lion, maybe a handful of berries is a good idea. For most of typical human endeavor, and for long term health, fat is the better fuel.

        As for proof, I don’t need to be convinced. I am on record (in another forum) for fasting three days and maintaining my level of exercise. Not “Elite” by any means, but beyond normal daily levels by quite a bit. I posted detailed records of activity and BG readings. If you want to find out if it’s possible, you will have to make the experiment yourself.

        Bill DeWitt wrote on May 24th, 2011
        • There is nothing to prove. Ask any elite athlete what they eat, and they will say carbs. Of course I can’t prove that ‘none do’, so you will have to be satisfied with the vast majority.

          And no, I still argue that a carb burning hiker could go 200 miles faster than a fat burning hiker, all else being equal, and given the carb burning hiker had access to carbs.

          Berries are nothing, barely any calories in them. Corn starch would be leagues better as a fuel source for high intensity exercise.

          The proof is in the (high sugar) pudding. If fat was a better fuel source, for explosive or endurance exercise, world class athletes would have made the switch.

          soahc wrote on May 24th, 2011
      • Man I don’t really want to step into this, but there are athletes that are currently doing paleo and talking about it.

        http://www.livingpaleo.com/guest/Greg-Parham-Talks-About-The-Paleo-Diet-For-Performance.html

        Additionally, many of the elite CrossFit guys run pretty strict Paleo.

        I’m not saying there’s not a place for carbs – no one is. In fact, all the big players in this (Loren Cordain, Robb Wolf, Mark Sisson) all advocate carbohydrate intake in addition to protein and fats. They also advocate more the more active you are. They just don’t advocate the carbs found in grains and legumes.

        Hal wrote on May 24th, 2011
      • Put a 25lb sack of corn starch on my hikers back, and they will hike out faster than your ketosis hiker who carries NOTHING. All else being equal, both being people of average fitness.

        YOU HAVE NO PROOF of this…

        You are taking what you know/believe.

        Why are there no athletes doing this?

        1) the entire SPORTS industry believes what you believe!

        The coaches and nutritionalists don’t know that they could do things differently.

        As you your mountain lion scenario – endurance is different to sprinting… and in a sprint situation, fats are a great fuel

        Also, your belief has been disproven… look at the links to the information people have posted, including the one I gave you above – both endurance and ability to maintain peak speed improved!!!

        2) regarding the gatorade thing – I’ll tell you why – cause gatorade couldn’t earn millions selling people sugared water if people realised a steak with some fats would mean you can perform without their product!!!

        The entire FOOD industry is skewed towards corn, soy, wheat and SUGAR – PERIOD… and they love having unquestioning lemmings like you that spout off about elite athletes as a reason to keep eating their crap.

        3) Even Mark (the author of this post) notes that if you are doing a lot of exercise, or competing at an elite level you can up your carb intake, because carbs are a cheap easy (and nasty fuel – like I said steroids get great performance – but not good for you)… But here is the FACTS, 99.99% of the population are NOT elite athletes – not even near it… and even more so more than 99.99999999% of the population will never be in your silly hike test, and even if they were – it would be ONCE.

        Actually the burden of proof rests on YOU… Just because a infinitesimal percentage of the population that engages in elite performance sport MAY (and again – it is yet to be properly studied) be better off using carbs as an energy source, the fact is this is NOT what normal life is, and so the burden of proof is on you to prove the higher carb, low fat method is good for everyone else, because ever SINCE we adopted the approach you are advocating (and ever since the likes of gatorade started selling their drinks to people that DELUDE themselves into thinking they are some sort of athlete) obesity, heart disease, diabetes, cancer, stroke, depression, crohns disease, MS have been on the rise, and it can be traced in nearly every country to when health authorities in each country started advocating the low fat – higher carb food pyramid…

        And anticipating you will bring up sedentary lifestyle… explain how before the 1970’s obesity was rising at a pace only a fraction of what it is today (increased sugar consumption – but no low-fat higher carb diet recommendation until the mid 70’s), yet belonging to a gym was near UNHEARD of, doing yoga, pilates, private personal training session – all the same – nearly ALL organised exercise just didn’t exist… the fact is in terms of total hours spent exercising there is MORE for a lot of people – and they are STILL overweight.

        It is DIET… you cannot out exercise poor diet and poor diet includes carbs – and ever since we were conned that carbs are good the WHOLE world is getting fat!!!

        Luke wrote on June 2nd, 2011
  13. OK, yes, if you manipulate the test until only a carb diet will be best, then the carb diet is best. Do you, in reciprocation, agree that if you don’t manipulate the test, if you only speak about the average person, the average athlete, in average circumstances, who wants more than to simply excel in a limited endeavor for a short span of years, that for this 99.99% of humanity, fats would be the better fuel?

    For instance, obviously LOX rocket fuel is a better fuel if you want to shove multiple tons off the Earth, but for driving around in daily traffic, gasoline is better and less likely to erode your car’s pancreas. What’s best for an abnormal person in an abnormal situation cannot reasonably be declared to be what’s best for all people.

    For the record though, for a long time, the best athletes in the world advocated cigarettes and beer. I’ll go with the biochemistry over athletes recommendation every time.

    Bill DeWitt wrote on May 24th, 2011
  14. Elite athletes stress their bodies in ways not necessarily healthy. Mark and pretty much all low carb/Primal/Paleo experts have repeatedly said that higher carbs are necessary for those athletes that insist on or are required to train for abnormally high amounts of time. See, for example, The Paleo Diet for Athletes. The whole point, that you’re missing, is that Mark is not concerned with fueling an elite athlete lifestyle because, again, elite athletes arguably put their bodies through unhealthy levels of stress that are dangerous in the long run or near impossible for the ordinary human to maintain.

    Matt wrote on May 25th, 2011
  15. To more fully answer the question, “Why don’t elite athletes use a low carb diet:

    Matt posted a fair and full response, but I want to say that perhaps they would try it – if the zeitgeist of the carb-loading athlete were not so strong. Pair that with the commercial drive to push the limits of human performance beyond normal limits and you have carb loading, steroids and other damaging methods. Does adding nitro to your household car improve speed bursts? Yes. Is it the preferred method of fueling your car? No.

    We may never know what athletes can do on a more evolutionary diet. I don’t expect the pendulum to swing that far back in the 20 years I might have left. It’s been 12 years since I left the carbohydrate addiction behind and I still can’t find a doctor who supports me in my diet, even though they hold the records in their hands. The CW, the myths, the USDA guidelines are just too strong, and have have the full force of Big Agri/Pharma Lobbyists behind them.

    Bill DeWitt wrote on May 25th, 2011
    • GROK ON>>>>

      Daveman wrote on May 25th, 2011
  16. I wouldn’t eat corn anything even if you paid me to….
    specially corn starch..
    choking down starchy dust?…not for me…Primal man did just fine without it and man can continue to do just fine without it..And some of the most EXPLOSIVE athletes I know..Eat Paleo/Primal …especially the Crossfit monsters…And I know em…and they wouldn’t eat corn anything either…

    Daveman wrote on May 25th, 2011
  17. Of all the things many humans, and particularly Americans have “forgotten” how to do, eating, tops the list.

    Extrapolate that across all of human activity and I shudder to think what that spells for us.

    smarmyrealist wrote on May 26th, 2011
  18. Of course, one thing I have to admit is that in nature, carnivores are NEVER able to outrun herbivores. Not ONCE, EVER! Which is why all carnivores died out so many millions of years ago…

    Bill DeWitt wrote on May 26th, 2011
  19. this link may point to some science for those so inclined.
    http://sciencenewsmagazine.org/pages/pdfs/data/1996/149-18/14918-20.pdf

    tim_lebsack wrote on May 26th, 2011
  20. How much can you increase your intake if you’re working out? Even on workout or really active days, I stay around 150, occasionally a bit higher. Still too low? Sometimes I find myself hitting a wall…

    Lisa wrote on May 26th, 2011
    • I think you have to play with it in order to figure out what is optimal for you and your level of activity. If you find yourself bonking out, then you probably need more easily accessible energy, and since it takes work and time to get additional energy out of fat, it makes sense that the body would preferentially select ready to go energy. So if you need more, take more in. Stop when you feel better.

      Hal wrote on May 26th, 2011
      • Looks like 170 is a good area for me, surprisingly! Might want to rethink 170 as an insidious weight gain zone. 😉

        Lisa wrote on May 28th, 2011
  21. I just want to make a small contribution to this thread in terms of “our neolithic ancestors” and high carb diets.

    I am an academic working cross-discipline in history, literature, classics, and politics, with a specific interest in the lives of the ordinary working classes from the classical period to the 19th century West.

    What people maybe do not realise is that, even two hundred years ago, “bread” was nowhere near the kind of product we produce and consume today.

    If you recreate the ingredients, which is possible in Britain as we still have a few working watermills with traditional mill stones to create the right kind of flour, and methods by which Western European people made bread in the early 19th century, you end up with a very dense, compact, heavy, close-crumb product that is very “meaty” in texture.

    It is very difficult to eat more than a couple of slices of these loaves, and they were made with traditional honey, not refined sugar. They were also very small, compared to what we see today. Remember also that the “white flour” of the time was not bleached, just sieved, and cost a premium that many could not afford. Cheaper flour was could be up to 50 percent husk.

    To go back to Tudor/Stuart England, the diets of rural English peasantry revolved around what they could grow in their small cottage gardens and what they could forage in forests. These people lived on bone broths with scraps of root vegetables and meat, and dairy products if they were wealthy enough to own a cow or some chickens. There were oats, however.

    Again, if you were wealthy in the Tudor/Stuart period, you ate meat. Lots of meat. All the time. In fact, what is noticeable is the link between obesity amongst the elite and merchant classes and the consumption of ale, beer, mead and wine.

    So it is not really accurate to say, if you are from a Western European heritage, that our “ancestors” in the last 1000 years ate high carb diets. It really depended on who you were, and where you were. Indeed, most non-elite/non-merchant class English people prior to the 19th century lived on what we would probably see as a rather Primal Diet — remember there is no rice, no pasta, and, before the Tudor period, no potatoes, and honey is the sweetener of choice. Pastry is made with lard or suet, and they didn’t really eat a lot of it.

    Alex wrote on May 29th, 2011
    • Hi Alex,

      Nice points you raise.

      The other issue is that even if you take the 10,000 years generally accepted as how long the human species has been eating grains, this is not as long as it sounds from an evolutionary point of view.

      If you take modern humans being about 200,000 years old in terms of physiology and metabolic functions, then 10,000 years is not that long. Put it on a 24 hour clock (NOT a 12 hour clock) and that means that we have only been eating grains for the last 72 minutes (out of 1440 minutes)!!!, or approximately 1 hour in the last 24.

      Now we may have adapted to tolerate this food source and certain individuals may even have genetic variation from the norm that allows them to THRIVE on this type of diet, but based on human history, and even allowing for the observed acceleration in evolution for humans in recent times it will likely be another 50,000+ years before we would have a sufficient portion of the population that has evolved to be “homowheatus” as I like to call them, and that would thrive on a high grain diet.

      Note the difference, in biology you can adapt to tolerate something, that does not mean you are at the point where you have evolved to THRIVE on that thing.

      Anyway, as you point out, few people would have appropriately adapted to a high carb diet within a 1000 year period.

      Also, the other common mistake people make when first reading about the Primal Blueprint or similar diets is that they think the no grains approach in the Primal Blueprint means low/no carb diet.

      It just means lower carb. With carbs still coming from non-grain sources. You limit your carbs by not eating grains and refined carbs of any kind.

      You can eat fruit, unless you want to maximise weight loss, and thus limit your carbs even more.

      At not stage (other than small fasts), do you reduce you carbs below an amount that could keep your brain ticking along on carbs if needed.

      Luke wrote on May 31st, 2011
  22. i didn’t read all of the pages of comment, so please forgive me if i’m redundant, but i highly recommend Sally Fallon’s “Nourishing Traditions”. it talks about what healthy historical cultures *really* ate, and one cookbook you have to read cover-to-cover! it’s co-authored by Mary Enig, who probably knows more about dietary fats than anyone in the world.

    tess wrote on May 29th, 2011
  23. I have a simple question: if fat is the preferred fuel, and you follow PB nutrition, then why do you state “There is a downside, however: you can’t train long and hard day-in and day-out in the fat paradigm”? Don’t all of us have plenty of fat to supply energy for endurance training?

    Kelly wrote on May 30th, 2011
    • I work HARD…and I lift HEAVY…and I pretty much live on less than 50 grams of carbs per day..everyday.I have no problems GROKKING along…Everyone comes from different evolutionary genetic stock..and we all are different and can
      handle it different.
      FAt…CArbs…PRotien…just do it fresh and with no processed foods.GROK ON>>>

      Daveman wrote on May 30th, 2011
      • No, from an evolutionary perspective, we are all the same.

        Seth wrote on May 30th, 2011
  24. This post is ridiculous. The body requires carbohydrate for brain function, which is a physiological priority. The body doesn’t prefer fat and ketones (ketone bodies are derived from fatty acids when carbohydrate in the body is scarce; a desperate mechanism to get a form of carbohydrate for the brain). Here’s an experiment to find out what fuel the body prefers: keep insulin (a protein hormone that facilitates the transport of glucose (carbohydrate) across cellular membranes) away from a type 1 diabetic and see what happens.

    Fat does become the predominant fuel used by muscle at low levels of physical activity, but it is not preferred, but only to spare carbohydrates for moments when it’s critical (physical activity/survival).

    Seth wrote on May 30th, 2011
    • @Seth: It has been determined by real scientists, using real science, that the brain functions just fine on ketones. You are free, of course, to continue on your superstition-based diet if you so chose.

      Howard wrote on May 30th, 2011
      • Actually, no it hasn’t. Do you have any idea how and why ketone bodies are produced in the body? Please cite the research article(s) by these real scientists demonstrating that the brain is okay with just ketones.

        Seth wrote on May 30th, 2011
        • Do you have any idea why type 1 diabetics go into a coma and die? It’s not superstition, it’s education.

          Seth wrote on May 30th, 2011
        • If carbohydrates are so necessary to the human body, how did we survive the last ice-age?

          Ann wrote on June 6th, 2012
        • And you are confusing ketosis with ketoacidosis. Different conditions, different diets. Ketoacidosis is only dangerous for diabetics.

          Ann wrote on June 6th, 2012
  25. Almost a custom for those who disagree with a well reasoned, fully documented and entertaining post to repeat assertions we’ve all heard many times before, as if repeating them makes them more like science. For the record, the body can and does produce all the glucose it actually needs, so dietary sugars and carbs are not needed. Any amount of blood sugar over about a teaspoon full per hour is toxic, as many reputable news sources are finally admitting these last few weeks. That’s why we have insulin, to move it out of the blood, and keep it form killing us. That’s why T1 diabetics need shots of it, not only so that they can use the sugar, but so that it’s not in their blood, killing them.

    Bill DeWitt wrote on May 30th, 2011
    • Wow.

      Sugar in the blood will not kill you. Excessive amounts get excreted in the urine.

      What reputable news sources?

      Seth wrote on May 30th, 2011
      • Yes, blood glucose levels for diabetics are never checked and a high number is not at all worrisome.

        bradley wrote on May 30th, 2011
    • As a current doctoral student in human physiology, previously completing a masters degree in exercise physiology, I’m telling you that you are completely misinformed. This is a perfect example of the misinformation floating around out there concerning metabolism. The striking part is how the misinformed cling to it and believe it.

      Seth wrote on May 30th, 2011
      • As a graduate of a degree with biochemistry and evolutionary biology, and someone with experience in the pharmaceutical industry (now out due to what I now know) and working in the area of Type 2 diabetes, I’m telling you that you are completely misinformed. This is a perfect example of the misinformation floating around out there concerning metabolism by those indoctrinated in the conventional wisdom of exercise physiology (i.e. personal trainers with an degree). The striking part is how the misinformed (especially those climbing the academic ladder of the conventional wisdom) cling to it and believe it (without question, cause it is already in my head!!).

        😉

        Too easy

        Luke wrote on May 31st, 2011
        • I recognise you are getting your doctorate in human physiology, but obviously that means you get to skip the basic information on physiology…. otherwise you would/should have learnt about things like the role of the hormone insulin in promoting fat storage and preventing fat burning, the lack of a decent glycogen storage system (despite your dogma that carbs are vital – of so vital we would have evolved a decent carb storage system to rival fat storage) and the fact that evolution for nearly all animals chose FAT as a storage mechanism, hence it must be fine to run your body on fat!!! Oh and the completely one sided view of energy in = energy out, ignoring (or being ignorant of) the fact this equation runs both ways and describes a relationship, not a cause.

          Luke wrote on May 31st, 2011
    • Bill DeWitt:”For the record, the body can and does produce all the glucose it actually needs, so dietary sugars and carbs are not needed.”

      yes and it’s one of the reasons why we survived those thousands of winters. Our ancestors’ brains didn’t stop functioning properly when we had to rely on hunting & fishing (zero carbs) as our only source of food for months. The “You need X servings of carbs or you’ll die!!!” crowd needs to look at evolution & how we survived in the past, not at the USDA Food Pyramid/Plate.

      Michael wrote on September 15th, 2011
  26. So when my vegetarian diet led my BG readings to be in the 700s instead of around 100, you are saying that this was not a problem? Can I quote you on that when they schedule my amputation?

    As for reputable news, Look it up. There have been plenty of links posted. That way you can use YOUR idea of a reputable source. But look for hyperglycemia, not “why sugar is good for you”…

    Bill DeWitt wrote on May 30th, 2011
    • No, I don’t condone a vegatarian diet, nor did I even mention it.

      You made a claim that sugar is toxic and that this information supported by reputable sources. You should provide the source.

      Seth wrote on May 30th, 2011
  27. Argument by Authority works a lot better when you cite your sources and offer your credentials…. still a logical fallacy, but one that fools more people.

    Bill DeWitt wrote on May 30th, 2011
    • haha – you must cite your sources!

      I don’t have to, because I’m educated!!

      I don’t know if you are educated too, and even whether you are MORE educated than I am, but as I am brimming with self pride in my academic “achievements” I will ASSUME that I must be smarter than you (I mean I have a masters and am studying a doctorate – what are the chances you are “smarter” than me!!!)

      I fail to recognise that obtaining a qualification does not equate to experience of even knowledge in the real world.

      I also fail to recognise that whilst in common language having a masters and studying a doctorate is considered being “an academic”, in academia, until you have done research, preferably resulting in some new facts being revealed to the world, not just confirming what is already known (or worse assumed), you aren’t really an “academic”.

      However, most people assume people with degrees, especially advanced degrees are smart, so they will be swayed by my use of my qualifications (completed and currently underway) as proof enough of the facts I state!!!

      😉

      Luke wrote on May 31st, 2011
  28. Unless your plan is to avoid the question, the type of diet is not important. Tell me you believe that a BG reading of 700 is not a problem, or admit that hyperglycemia is one of the major causes of the eventual death of T2 Diabetics.

    If you have not looked up hyperglycemia by now, then you don’t want to learn, you just want to argue.

    Bill DeWitt wrote on May 30th, 2011
    • The major causes of death of type 2 diabetics are heart attack and stroke, not hyperglycemia.

      A BG of 700 is not good; it’s a problem. A BG of 700 doesn’t happen because carbohydrates are bad; it happens because of a poor diet and no exercise. A BG of 700 often occurs because the individual is insulin resistant (again, due to a poor diet and no regular exercise).

      I don’t need to look up hyperglycemia. Also, I always like to learn. That’s why I’m a graduate student.

      Seth wrote on May 30th, 2011
      • Ah Seth,

        The graduate student makes you a master of all information.

        Well I have worked with, and learnt from some of the leading endocrinologists and other specialists in the world that treat Type 2 (and Type 1) diabetes, including some at institutions such as the International Diabetes Institute.

        Your statement:

        “The major causes of death of type 2 diabetics are heart attack and stroke, not hyperglycemia”

        …is like saying the leading cause of death for gunshot victims is ingress of a bullet, not the firing of the gun.

        The damage to the vascular system, including the regulation of blood pressure by the kidneys is damaged by CHRONIC hyperglycemia. As a result after YEARS of elevated blood glucose (hyperglycemia) the damage to the vascular system results in heart attacks and strokes. DUH!!!

        Regarding your hypothesis that high blood glucose only occurs due to poor exercise and diet – again this is FALSE (e.g. Type 1 diabetics).

        You state “No, from an evolutionary perspective, we are all the same.” Whilst there is some truth to the fact we all evolved from likely a single female human ancestor, it is also a fallacy to state we are all the same in terms of evolution… CLEARLY there are physiological differences between people, some due to race, yet even within a race, there is genetic variation (in fact the variation is larger within a particular race). If you TRULY are studying to attain your doctorate in human physiology, I really do hope they teach you this basic fact. Even in conventional medicine it is recognised that certain people react differently and metabolise certain compounds differently from others. Proof of this is the fact that some people can take a drug with no effect, others taking the same dose can end up with severe side effects and even be so sensitive they die… clearly we may have a common evolutionary source, but we are NOT the same in terms of evolution, as environment and other factors shape our evolutionary path.

        You state:

        “The body requires carbohydrate for brain function, which is a physiological priority. The body doesn’t prefer fat and ketones (ketone bodies are derived from fatty acids when carbohydrate in the body is scarce; a desperate mechanism to get a form of carbohydrate for the brain). Here’s an experiment to find out what fuel the body prefers: keep insulin (a protein hormone that facilitates the transport of glucose (carbohydrate) across cellular membranes) away from a type 1 diabetic and see what happens.

        Fat does become the predominant fuel used by muscle at low levels of physical activity, but it is not preferred, but only to spare carbohydrates for moments when it’s critical (physical activity/survival).”

        SO MANY errors here it will take some time:

        1) Even if the brain needs carbohydrate as a preference, this does NOT equate to needing carbohydrate in the diet. It is a medical and scientific fact (and no I have no references at hand, as this is considered BASIC common knowledge – especially for someone as “educated” as you) that there are NO essential dietary requirements for carbohydrates. There ARE essential amino acids and fats, without them our bodily function is compromised. There IS a process in the body that converts proteins into carbohydrates (gluconeogenisis). This is a function of the liver, and is in fact one of the dysfuntions Type 2 diabetics suffer (their liver produces excess glucose, even when the blood glucose levels are already elevated). This is such a significant problem, that many of the new drugs for Type 2 diabetes under development target this process. If there is sufficient protein in the diet (in excess of basic needs), any excess can be converted into glucose vis gluconeogenisis. This is why body builders that eat too much protein, don’t realise most of the excess is pissed out or converted into glucose.

        The “experiment” is SUCH a fallacy and an example of poor debate on your part. Type 1 diabetics have a VERY different aetiology to Type 2 diabetics, and if you are in fact as educated as you claim to be you SHOULD know this, and as such you are either truly ignorant, or being deceptive so as to confuse those that may not know the difference.

        Type 1 diabetics have a condition that means their pancreas no longer produces sufficient insulin (if any at all). In the absence of ANY insulin, the body cannot utilise glucose. Additionally, as there is no insulin the bodies fat cells are signalled to release fatty acids as a energy source, and the type 1 diabetic quickly emaciates, additionally in certain cases they can enter diabetic ketoacidosis. If you do not know this, diabetic ketoacidosis is NOT the same as being in ketosis.

        The key here is the “acidosis” in ketoacidosis. All acidiosis states can be lethal (there are others other than ketoacidosis). They are essentially acidification of the blood.

        This is NOT the same as having ketone bodies in your blood stream, to suggest so is misleading.

        From wikipedia:

        “There are two major causes of ketoacidosis:

        Most commonly, ketoacidosis is diabetic ketoacidosis (DKA), resulting from increased fat metabolism due to a shortage of insulin. It is associated primarily with type I diabetes, and may result in a diabetic coma if left untreated.[4]

        Alcoholic ketoacidosis (AKA) presents infrequently, but can occur with acute alcohol intoxication, most often following a binge in alcoholics with acute or chronic liver or pancreatic disorders. Alcoholic ketoacidosis occurs more frequently following methanol or ethylene glycol intoxication than following intoxication with uncontaminated ethanol.[5]

        Ketoacidosis may also result from prolonged fasting or when following a ketogenic diet.[6]”

        I have included this last statement, as it is true, it MAY result from following a ketogenic diet, however you would have to be following it in the EXTREME. In fact outside of alcoholics and type 1 diabetics it is VERY rare, and even for them it is not at all a very common medical problem.

        You state:

        “You made a claim that sugar is toxic and that this information supported by reputable sources. You should provide the source”

        Two things here:

        1) Whilst I do not have references at hand (I am in a hotel at the moment), look up glucotoxicity. Again, in research with non-diabetics, pre-diabetics, Type 2 and type 1 diabetics there is evidence that elevated blood glucose (and not even that much mind you) has DIRECT glucotoxicity effects on the pancrease, in particular the beta cells (the VERY cells that produce insulin, which would in some way reduce the problem). This, as one professor in the area mentioned to me, is the great irony of the human body, the very cells that produce the hormone to reduce blood glucose are themselves DAMAGED by excess blood glucose. As a result if they fail to keep up with the amount of carbohydrate consumed (simple, complex, low GI or high GI – they ALL end up as glucose), they then get hammered, resulting in a reduced ability to keep up in the future. In fact, this fact suggests when we evolved we were not consuming vast amounts of glucose, if we did, there would be another mechanism that would have evolved to accommodate the beta cells that were damaged. We never evolved this system, because we never ate vast quantities of carbohydrates until we worked out how to access the carbs from the previously toxic grains and legumes we learnt how to cook enough to reduce their toxicity.

        2) You admonish others for not supplying references for their claims, yet you have NOT ONCE done the same. You use your education as you reference. Well sir I will invoke the same as you. I invoke me degrees in biochemistry and evolutionary biology, and years of experience in the pharmaceutical industry (reading countless journals in this topic), as well as my working in the area of type 2 diabetes. I acknowledge I don’t have a masters or a soon to be PhD, but then again, perhaps that is why I am not caught in a delusion that everything I learnt is absolute truth, and I don’t have the neurosis of using my education as a crutch to remain blinkered to any other views of the world. The fact you are a recent graduate and straight into a doctorate suggests to me you are someone heavy with education, but lacking life experience.

        You state you KNOW better than us because of what you learnt in attaining your masters degree in exercise physiology and during your current studies to attain your doctorate in human physiology… what an appalling state of affairs in the education system, when such an obvious flaw in your logic is beyond your recognition.

        What if what you have been taught is wrong? Just because you have a degree (masters or even doctorate) in bullshit, doesn’t make the bullshit any less composed of faecal matter from a bull!!!

        As this post points out, the conventional wisdom (i.e. what you have been taught and re-taught without question) is WRONG.

        Instead of trying to understand WHY this is different to what you have been taught, and instead of seeking new knowledge, you simply jump to the defence of what you already know!! What a poor standard of doctorate they now provide if you NEVER learn to ask whether the current knowledge is actually right!? That is the POINT of being educated, having the ability to question, not just defend what you already have in your head.

        Finally, the issue you and all your exercise and human physiology lecturers have failed to recognise is a few simple questions:

        1) If are bodies are incapable of utilising fat as an energy source (as is suggested here), and MUST have vast amount of carbohydrates in order to function – WHY did evolution for ALL animals choose fat storage as a survival mechanism? The human body, and that of most animals stores a pathetically small amount of glycogen (stored glucose for those unaware of the techno talk) in the muscles and the liver mostly. If we needed carbs to survive, ALL animals, including humans would have evolved a better and more capable glycogen storage system!!! This is just LOGIC – don’t need a masters or PhD to work that out!!!

        2) Again, if we NEED carbs to function, and especially the brain, then HOW did we evolve and grow most of the increases in human brain function during a period when we would have had LIMITED access to carbohydrates?? Prior to the utilisation of grains approx. 10,000 years ago (or at a stretch 30,000 for a single tribe as was recently discovered), there are little to no other significant sources of carbohydrate for the human species. By 50,000 years ago we had evolved way beyond apes and already had language, music, and other complex brain functions. HOW if what you say about carbs is true? ALSO how did we survive as a species in colder climates with limited access to even green leafy plants for significant portions of the year if we NEED carbs to function? We survived because proteins and fats and organ meats give us the necessary amino acids, vitamins, minerals and essential fats we need. The protein also provided a means for the liver to utilise gluconeogenisis to provide whatever carbs need we may have had in excess of the ketones our bodies and brains can use.

        3) If carbs are so good, why is it that since the advocation of high carb/low fat diets the rate of type 2 diabetes and obesity has skyrocketed? This is a FACT, look at the epidemiology data. In cultures where this was not advocated until later, the increases came later. This is NOT just due to lower levels of physical activity, as even in populations where physical activity has increased, the switch to higher carb diets has resulted in increased type 2 diabetes and obesity.

        Finally – The fact is insulin, which is not excessively excreted when there is less carbs in the diet PROMOTES fat storage in the body. This is one of the MAIN functions listed for insulin in almost ALL biochemistry and endocrinology texts. When insulin is present, fat cells are signalled to STORE fatty acids and convert glucose to fatty acids to store them. If you want anecdotal evidence of insulins weight promoting ability, ask ANY GP, endocrinologist, diabetes educator/nurse or diabetic. As SOON as someone is put on insulin, even if they exercise MORE than they did previously and eat less, they will put on weight. Of course it is HARD for them to eat less, as another problem with insulin is that it can OVERSHOOT the reduction in blood glucose, leading to hypoglycemia (blood glucose too LOW) which is at best dangerous, and worst this is FATAL. As a result, with blood glucose too low, the NATURAL response by the body to this problem is HUNGER (this is BASIC physiology – I trust you understand this – if you don’t HAND YOUR MASTERS back and save your money on your doctorate and go back to some 1st year biochemistry). As a result, the subsequent weight gain is an insidious cycle, as the insulin promotes fat storage of the calories consumed, and then lowers blood glucose, resulting in hunger and calorie consumption, and then the cycle repeats.

        IF you had actually WORKED with any type 2 diabetics, you would know that not all are just lazy as you suggest. Sure, some are, but here is the kicker, one of the effects of HYPERglycemia is lethargy, which leads to reduced caloric expenditure, which leads to higher levels of hyperglycemia.. again another twisted vicious cycle.

        Also recent research in Type 2 diabetes has demonstrated that regardless of blood glucose level, the use of insulin is associated with an increased risk of heart attack and stroke.

        OK, the real finally – the conventional wisdom that it is only overeating and laziness that causes type 2 diabetes and obesity is ignoring the fact that the energy systems (i.e. metabolic pathways and feedback loops) are not unidirectional. And this does take some understanding of thermodynamics (which I learnt in biochemistry – did they teach that in physiology?)… but the equation flows both ways.

        Gary Taubes has a great explanation of this, but essentially you are applying causation, when all you can observe is a relationship.

        If you say calories in = calories out is the equation then the equation works both way, i.e. calories out = calories in!

        So if you eat 2000 calories and then use 2000 calories you end up net zero. However it works the other way – if you USE 2000 calories, your body needs 2000 calories, and so it seeks 2000 calories. We know this is true, as people like Micheal Phelps eats many times the normal calories, due to the caloric expenditure he has. The calories USED DRIVES the calories consumed.

        Continuing, less calories in = less calories out, again in people that are starving, this is reflected in lethargy.

        So what about if you eat 2000 and you expend 2000 calories, BUT 200 (10%) calories you eat get stored and locked away before you can use them (and this is WHAT excess insulin does, it stores the calories BEFORE they can be used – it lock away fatty acids). Now you have used 200 calories more than you have available, your body has TWO possible responses:

        1) Eat 200 calories more (with 20 (10%) stored like before), so you need another 20, with 2 stored, so you need another 2 – all up an extra 222.2 calories consumed, with 222 stored as fat. This manifests in the “real world” as someone “overeating”

        OR

        2) you reduce your energy expenditure to 1800 (with the 200 still stored as fat). This is deemed in the “real world” as someone becoming less active or sedentary.

        In this way it is possible that fat storage leads to lethargy and overeating.

        You CANNOT say calories in = calories out and accept that as fact, but then refuse to acknowledge that in a biological system that has feedback loops for survival that the reverse is not ALSO true, i.e. the amount of calories used is related to the amount of calories consumed, and the amount of calories that can be used, is also affected by how many are available. If you cannot access the calories, because the excess insulin has caused storage then it is entirely logical that this will result in either lethargy and/or excessive consumption of calories.

        You are basing your entire arguments on what you have been taught, yet simple logic, basic biochemistry, endocrinology and thermodynamics demonstrate that your arguments are lacking in basis in simple facts, and are only supported by your belief that because someone with an academic degree taught you it whilst you obtained the same academic degree they must be true.

        Start using that overeducated brain of yours and apply the scientific method of investigation and query to this stuff and whilst you may find you wasted tens of thousand of dollars on the facts your were taught during your education, at least those tens of thousands of dollars would have amounted to something, by equipping you with you skills and knowledge to challenge the status quo and forge ahead with new lines of thinking and insight. Again, some of the top, scientists, cardiologists, endocrinologists, biochemists and even exercise physiologists in the world are recognising this – go on, back yourself to be ahead of the scientific herd, trust me NO great scientist just accepted what he or she was taught!!!

        Luke wrote on May 31st, 2011
        • Please excuse typos – was just belting this long post out… notable errors (there is likely more):

          “I invoke me degrees in…” should be “I invoke my degrees in…” (always dangerous editing “let me” into something else on the fly)

          “If are bodies are…” whoa – one too many are’s and one few on the our’s… Should be “If our bodies are…”

          Luke wrote on May 31st, 2011
        • Again, my point is that it is wrong to think that the body is designed to rely solely on protein as a source for glucose (gluconeogenesis). This is the claim that the author of this article is making. My point in response to others is that carbohydrate is not toxic, and that it is important for the body, particularly the brain.

          To reiterate my point, inadequate amounts of carbohydrate intake is not advantageous for the brain. I did not say that an excessive amount of carbohydrate intake is okay. I did not say that our bodies don’t need adequate amounts of fat and protein. Our bodies do not function optimally with zero carbohydrate intake. I think anyone would agree that humans evolved eating vegetables and fruits (plenty of carbohydrate), along with other sources of protein and fat.

          I reveal my education status only to show that I’m not some schmuck posting random stuff, not because I think I’m smarter than everyone.

          I understand the role of liver, gluconeogenesis, and the cycle of proteins to carbohydrate, and carbohydrate to fat, etc. As a biochemist, certainly you understand that protein conversion to carbohydrate in the liver also produces ammonia. If the body were to rely solely on protein in for gluconeogenesis, due to a lack of carbohydrate intake, this would obviously become problematic. Excessive cycling of the urea cycle would cause a protein imbalance.

          I did not say that our bodies are “incapable of utilizing fat as an energy source.” I did not say that our bodies “MUST have vast amounts of carbohydrate in order to function.” I’m saying that our brains need an adequate amount for optimal function.

          Also, the major causes of death of type 2 diabetics are heart attack and stroke. You can get this information from the CDC. Of course, chronic hyperglycemia initiates the disease state. The point is that you will not typically see “hyperglycemia” on the death certificate of a type 2 diabetic.

          Seth wrote on May 31st, 2011
        • I will admit that the type 1 diabetic “experiment” isn’t appropriate. It doesn’t address the authors point.

          Seth wrote on May 31st, 2011
  29. OK, let me walk you through this one step at a time – What CAUSES heart attack and stroke in T2 Diabetics?

    Bill DeWitt wrote on May 31st, 2011
    • Bill,

      EXACTLY!!!

      I worry about the academic integrity of the current university system if people with masters that are studying doctorates cannot understand the difference between a cause and an effect!!!

      I guess this whole Seth thing proves what we already know – busting the conventional wisdom is going to take a long time, when even the (so called/self professed) best and brightest science graduates are so indoctrinated and brainwashed to the point they abandon all scientific curiosity and leap to the defence of what they have been taught, rather than seeking to understand a bit more about a different point of view.

      I wish I wasn’t travelling, I would have love to have dosed up the references and also written something a little less stream of consciousness.

      However as your next post states, this guy thinks he knows everything already, so no doubt I wasted my time… or perhaps not, perhaps someone with a true scientific mind of curiosity and interest will read it and take a new perspective from it!?

      Luke wrote on May 31st, 2011
      • I do believe that a restricted calorie diet is the most healthy choice. My point is that the body does not function optimally in starvation mode, and that constant gluconeogenesis without any carbohydrate intake is not a normal and healthy state for the body.

        Seth wrote on May 31st, 2011
        • “I do believe that a restricted calorie diet is the most healthy choice. My point is that the body does not function optimally in starvation mode,”

          Ummm really, restricted calories is good, but starvation is bad!!!

          Make up your mind!

          The author does not say to eat ZERO carbs (look at the information), so you are arguing about nothing… grow up.

          OK, now you must cite your sources!!!

          “constant gluconeogenesis without any carbohydrate intake is not a normal and healthy state for the body.”

          Where is your source for this?

          Explain Inuit populations, or other populations in Africa that do not eat carbs?

          Explain how we as a species survived ice ages?

          Just because it is not what you are used to, does not mean you can make a claim like this!?

          Again I ask, if the lack of carbohydrate is SO BAD for a human body (or that of any mammal), WHY did we evolve with such a WOEFULLY inadequate glycogen storage system???? You MUST be able to explain this.

          Evolution by natural selection MEANS that if this was absolutely necessary, we would have evolved a better glucose storage system – PERIOD.

          We didn’t evolve this system, because it DOES NOT MATTER or do harm to a human body to be in a state without exogenous glucose from carbs.

          We CAN and do have a system for creating glucose in the body, we do not for certain fatty acids (i.e. fats) and certain amino acids (i.e. proteins)… You JUST IGNORE this, because you have ho answer.

          Cite YOUR sources to make such an outrageous claim that living without a carbohydrate intake is not normal or healthy, when the evolution of the entire animal kingdom demonstrates otherwise.

          Luke wrote on May 31st, 2011
    • “I think anyone would agree that humans evolved eating vegetables and fruits (plenty of carbohydrate), along with other sources of protein and fat.”

      SOURCE PLEASE!?

      1) Vegetables are NOT a plentiful sources of carbs.

      2) And unlike your pampered existence, fruits are seasonal. You are applying your 21st century understanding of the food chain to our human evolution.

      Fruits don’t become fruit all year round. So they were limited to when available. Just because you can walk into a Whole Foods and buy fruits at any time of the year does not mean that is how we evolved – seriously – you have a masters and are getting a doctorate?!

      3) The fruits we most commonly ate were berries, we also ate nuts. We lost our ability to climb, so we in essence ceded fruits high in trees to our ape cousins until we worked out tools to get them down. Berries are NOT high in carbs (relatively)

      “If the body were to rely solely on protein in for gluconeogenesis, due to a lack of carbohydrate intake, this would obviously become problematic. Excessive cycling of the urea cycle would cause a protein imbalance”

      What are you doing – just arguing to show how smart you are?! NOT ONCE in any part of this site does the author EVER suggest NO carbohydrates – EVER, so your point is irrelevant (and revisionist).

      The author recommends berries (is not so keen on bananas as they are VERY high in carbs), and does recommend fruit. Mark (sorry over calling him the author), advocates MOSTLY green leafy things as the basis of the dietary recommendations (by the way the Primal Blueprint is MORE than a diet – you wouldn’t know this, because you are just arguing, telling us we are so misinformed, without checking what is actually being recommended – which is worse misinformed, or just uninformed?!)

      “I’m saying that our brains need an adequate amount for optimal function.”

      CITE YOUR SOURCE!!!

      I don’t have the references with me, but in well designed tests where those on ketogenic diets were compared to those on regular diets the cognitive functions were equal. The only studies where this isn’t these case have a design flaw. If you switch from a carb heavy diet to a low carb diet, then it is a KNOWN fact that it takes up to two weeks for the body to get back into full swing burning fats. So if you do a test where you take high carbers (and that means people that eat pasta, bread and rice) and then switch them to low carb and test them immediately, they will do worse.

      This fact supports the theory that we evolved with very low carbs in our diet.

      If we did have high carbs and each time we ran out (which would have happened often in prehistoric past human life) and it took weeks to get back to optimum, then we would have evolved to not have that lag (because being impaired in this way would put you at risk, and those that switched quickly would have had a survival advantage).

      The fact this lag persists to today means we DID not have high carb diets that then resulted in us having a lag in switching back to low carb. We just were low carb most, if not all the time.

      We then rarely got some carbs, but this did not occur for so long that we needed to “switch back to low carb” and adjust.

      I mean this is SIMPLE deduction using evolutionary theory.

      “Also, the major causes of death of type 2 diabetics are heart attack and stroke. You can get this information from the CDC. Of course, chronic hyperglycemia initiates the disease state. The point is that you will not typically see “hyperglycemia” on the death certificate of a type 2 diabetic.”

      And who said that hyperglycemia is the cause listed on the death certificates of type 2 diabetics?!

      You are being revisionist here… you are trying to weasel out of the fact that you made this stupid statement!

      The previous poster stated:

      “hyperglycemia is one of the major causes of the eventual death of T2 Diabetics”.

      Whilst this is not perfect stated, only someone trying to be a smart arse would try and say that this post was suggesting that hyperglycemia is what is listed in the death certificate.

      There you go again with the use of “higher authority” by calling on the CDC… WHY?

      In my answer I stated:

      “The damage to the vascular system, including the regulation of blood pressure by the kidneys is damaged by CHRONIC hyperglycemia. As a result after YEARS of elevated blood glucose (hyperglycemia) the damage to the vascular system results in heart attacks and strokes.”

      Clearly I am aware that heart attacks and strokes are the listed cause of death, but the cause of the heart attack and strokes is hyperglycemia – FACT, don’t need the CDC, I have worked in the area, and you were being smug in your original post and now are trying to say you were just misunderstood.

      Luke wrote on May 31st, 2011
  30. No, you know what, never mind. Since you refuse to look up the recent information on the subject, you are not interested in learning. You believe you already know everything. Good luck in your future endeavors.

    Bill DeWitt wrote on May 31st, 2011
    • I don’t think I know everything. I’m saying that I do know what hyperglycemia is and that I don’t need to look it up.

      Seth wrote on May 31st, 2011
  31. Luke, thanks for taking the time to write all that. I Had to laugh at the “bad diet and no exercise” myth, since I grew most of my own food, ate nothing but whole fruits, vegetables and “healthy grains”, and worked out 4 days a week with a trainer, and ran the other three days. I ate better and exercised more than the average human, but the excess amount of carbs in my diet caused (surprise!) an excess of carbs in my blood! Now, I have cut back the dietary carbs to a metabolically insignificant amount, and (double surprise!) have had 10 years of rock stable BG readings. I am so sure I am going to listen to some guy on the internet who claims to have studied something as opposed to the many practicing cardiologists, PHD biochemists, and long term successful T2 Diabetics. I happen to be working on an advanced degree in Biochemistry and I can already point to the many mistakes in basic assumptions in my text books. I just learn it the way they tell me and wait until I can be the one writing the books and teaching the classes.

    Bill DeWitt wrote on May 31st, 2011
    • A poor diet that includes excessive calorie intake, and no regular exercise, does lead to chronic hyperglycemia type 2 diabetes. Type 2 diabetes is typically reversible with calorie restriction (a balanced diet) and/or exercise.

      I’m trying to put together what you’re saying, and it sounds like you’re saying that eating only fruits, vegetables and grains, and exercising 7 days a week caused blood glucose levels of 700. That obviously doesn’t sound right. Please clarify, or at least tell the whole story.

      Seth wrote on May 31st, 2011
    • Haha – gold… let me know when you publish, I’ll buy that book!!!

      However I assume you mean a text for physiology, as in biochemistry texts, all the basic information is already there!!!

      At least when I was studying, they described the pathways etc (without the dogma of fats are bad/carbs are good/proteins are depends on who you ask), then it is clear that the human biochemical pathways (and in fact mammalian biochemical pathways) favour fatty acid utilisation in a great number of situations.

      The hormonal function of insulin is clear, it allows glucose transport into cells and promotes fatty acid biosynthesis from carbs and fatty acid storage in the fat cells. In the absence of insulin this process is reversed. The hormone glucagon (essentially “anti-insulin”) promotes the reverse process (i.e. breakdown of fatty acids for use as energy and the release of fats from fat cells). These are not debatable – these are biochemical FACTS.

      Additionally Glucagon signals the liver release glucose into the blood stream and promotes gluconeogenisis from amino acids. Glucagon is suppressed by the release of insulin.

      The consumption of ANY food releases insulin (and down regulates as a result Glucagon), however the presence of carbohydrates (particularly refined carbs and fructose) result in a significant spike in insulin, and a subsequent drop, which can induce hunger. Fats and proteins are more slowly absorbed, and as a result do not invoke such a large insulin spike. As a result glucagon is able to produce glucose if needed, and with the lower insulin levels fatty acid oxidisation (i.e. fats as fuel) is able to occur.

      Again these are facts of biochemistry.

      Based on these facts of biochemistry the worst meals in terms of weight gain are:

      1) high fat & high carbs. Huge insulin spike, fats shuttled into fat storage AS WELL AS THE carbs converted into fatty acids for further fat storage. Stored fats not available for use (high insulin levels lock it in – and promote insulin resistance too), meaning you feel hungry for calories to make up the shortfall between the amount available from your meal and what you are using, so you EAT more than you would normally to get the SAME amount of available calories for your body to use. Worse still, high insulin spike results in HUGE blood glucose drop (carbs stored as fat and what is left is rapidly used), resulting in low blood glucose, leading to feelings of hunger. With the combination of stored calories and blood glucose drops, even if you manage to ignore your hunger and hot eat, you end up with feelings of lethargy, as you have less energy available, especially when insulin resistance develops due to the excessively high insulin levels, because even if you eat more, your muscles now can’t absorb the energy. High carb and high fat meals are a double whammy!!! Biochemistry facts, don’t need a masters of PhD to work this stuff out

      2) High carb low fat meals (but still high in calories). Pretty much the same as above, except you wont store as MUCH fat (less to directly store), but still some carbs get converted due to high insulin. Same result in less available calories, so need to eat more, similar Blood Glucose crash, so similar feelings of hunger. High insulin levels also result in insulin resistance, with subsequent weight gain, reinforcing insulin resistance and also the lethargy cycle described above.

      3) Just and average mix of all three nutrients. with enough exercise you may avoid weight gain for some time. Likely to result in slow insidious weight gain that creeps up over 5-10 years, eventually tipping the system enough to result in a rapid weight gain and perhaps some pre-diabetic symptoms. You believe the exercise physiologists of the world and cut out some fat from your diet (and end up at point #2 above!!!)

      4) Primal/paleo approach. Mid-level carbs (not low carbs), moderate protein and high/er fat. Moderate insulin response, with possibly glucagon available if needed. Insulin levels are such that fat storage is minimised if at all present, however fat release is not promoted either. Weight is maintained easily. Energy levels are fine, as amount consumed = amount available, and also lower insulin levels and body weight in normal range means little if any insulin resistance.

      5) Primal/low carb. Lower carb level, moderate protein and high fats – only when seeking to lose weight. Very low insulin response. Absence of carbs in diet promotes glucogon release and gluconegenisis. This triggers fatty acid release from fat cells, fatty acid oxidisation and ketones do form. Energy pouring out of fat cells, results in increased available energy, so eating less calories is easier, without hunger, and still meeting calorie expenditure needs. Once you reach your target weight, you up the carbs to kill off ketosis and jump back up to #4 above to maintain weight.

      All of this makes biochemical (and endocrinological) sense. It is consistent with known biochemical pathway and hormonal systems understanding and facts.

      The alternative that you can eat like #2 and lose weight is bullshit… only way is to cut calories or up exercise, which most people can’t maintain due to resulting hunger and lack of available energy (insulin levels still promoting storage if possible) – granted excessive deficits will result in fat being released – but inefficient and sadistic way to lose weight compared to #5/#4 which are biochemically and hormonally the easiest way to do it.

      Of course those that build their living on people needing to be cajoled/hounded/berated by a personal trainer or dietician has a significant conflict of interest in accepting anything but approach #2, as it is the approach that maximises the need for their services!!!

      That is why I have left pharmaceuticals. After discovering MDA, Primal Blueprint and all the other information I have researched in scientific papers and textbooks since, I realised that that industry, whilst it did not create this myth of how to lose weight, it is profiting from this awful error in human understanding. So now I spend my time ripping apart the flawed logic in those still clinging to conventional wisdom… of course working in pharmaceuticals I was trained on how to promote conventional wisdom and confuse others when they noticed it’s flaws (Seth used the most common used by pharma – the “higher authority/academic backing” card)… with that knowledge I find it easy to pick the blatant holes in their arguments and point them out for the fallacies that they are… Hopefully I can use that to help a few people see that conventional wisdom, and hence medicine and health authorities have bet the collective health of the human race on a flawed premise about human metabolism…

      Cheers,

      Luke

      Luke wrote on May 31st, 2011
      • I’m in agreement with this.

        What blatant holes are there in my argument? The author of this article insists that we don’t need to consume carbohydrate because the liver creates all the carbohydrate we need. Yes, the liver can produce carbohydrate, but overall this is a misunderstanding. The author has taken a know piece of biochemistry and has spun it out of control.

        I list my academic achievements to make the point that I have formal education.

        For the record, I’m not a personal trainer, or work in any industry, or cling to any “conventional wisdom.” I’m an extreme opposite. The incorrect “conventional wisdom” out there appears to be that diet and metabolism must be incredibly complicated, and that there’s some secret to eating well and losing weight. For example, the author of this article suggests that we all need to completely do away with carbohydrates because he/she heard about gluconeogenesis in the liver. That’s great if one wants to lose weight, but it’s not sustainable.

        Again, what you typed about the body’s biochemistry and physiology is basically correct. But I’m not sure what your point is and how it relates to the author’s article.

        Seth wrote on May 31st, 2011
        • Again – you have decided to argue, without checking your facts.

          1) The author (Mark) actually advocates eating is easy, his easy just limits carbs by excluding grains. You are hung up that your easy is the right easy.

          2) Repeated studies and empirical evidence show that restricted calorie diets are NOT easy and as a result FAIL, again and again and again.

          3) The Author (Mark) NEVER, not ONCE stated to eat no carbs… you are misleading stating this:

          Let me copy the text here, if it is TOO hard for you to scroll to the top of the page and read it:

          “So How Much Glucose Do You Really Need?

          Much less than most people assume. At any one time, the total amount of glucose dissolved in the bloodstream of a healthy non-diabetic is equivalent to only a teaspoon (maybe 5 grams). Much more than that is toxic; much less than that and you pass out. That’s not much range for a so-called “preferred” fuel, is it? Several studies have shown that under normal low MET conditions (at rest or low-to mid- levels of activity such as walking and easy work) the body only needs about 5 grams of glucose an hour. And that’s for people who aren’t yet fat-adapted or keto-adapted. The brain is the major consumer of glucose, needing maybe 120 grams a day in people who aren’t yet on a low carb eating program. Low carb eating reduces the brain’s glucose requirements considerably, and those who are very low carb (VLC) and keto-adapted may only require about 30 grams of glucose per day to fuel the brain (and little-to-none to fuel the muscles at <75% max efforts). Twenty of those grams can come from glycerol (a byproduct of fat metabolism) and the balance from gluconeogenesis in the liver (which can actually make up to a whopping 150 grams a day if you haven’t metabolically damaged it with NAFLD through fructose overdosing). Bottom line, unless you are a physical laborer or are training (exercising) hard on a daily basis, once you become fat-adapted, you probably don’t ever need to consume more than 150 grams of dietary carbs – and you can probably thrive on far less. Many PBers do very well (including working out) on 30-70 grams a day."

          Where is the ZERO?

          Mark even includes a GRAPH (pictures are easy aren't they?) that shows that he has three zones with 100-150 being effortless weight maintenance, 50-100 effortless weight loss and <50 Ketosis / intermittent fasting…

          "the author of this article suggests that we all need to completely do away with carbohydrates because he/she heard about gluconeogenesis in the liver. That’s great if one wants to lose weight, but it’s not sustainable."

          I call BS…

          This guy hasn't just heard about gluconeogenisis in the liver… I'm not going to bother to do your intellectual works for your, go and read about him AND HIS qualifications, seeing that is all that matters to you!!!

          Secondly ALL the information he gives states that the lower levels are for weight loss, and that the sustainable level is between 100-150.

          This is in EXCESS of the daily requirements of the human brain, and is above ketosis – did you EVEN READ this article before deciding to attack it from your pseudo-intellectual ivory tower?

          "A poor diet that includes excessive calorie intake, and no regular exercise, does lead to chronic hyperglycemia type 2 diabetes."

          True – but what you have now done is state a fact, and inferred that means everything else you have said is therefore right.

          You have YET to identify (let alone cite) a substantial reason that this approach that Mark writes is not a healthy diet. Your reasons are based on FALSE assumptions of what he has said. You even assume he means no fruit or veg, yet if you read his recommendations, you would see that veg are the basis of his food pyramid and many fruits (not all) are part of the recommendations too. He also has an 80% rule, which is follow it at least 80% of the time and don't obsess over things if you stray, as he firmly believes that people make it all too complicated.

          "Type 2 diabetes is typically reversible with calorie restriction (a balanced diet) and/or exercise"

          For as long as the calorie restriction lasts. A ketogenic diet has repeatedly been shown to be the most effective at reversing type 2 diabetes. There are papers galore on this, and I have also witnessed it with living breathing type 2 diabetics.

          The low fat high carb approach (even the whole low GI thing) is torturous for the reasons I outlined in the post that described the diet approaches. You ask them to exercise, and yet you give them a diet that does not allow them to maximise energy expenditure.

          A Ketogenic diet opens the fats cells to releasing fats – this is a biological/biochemical/endocrinological FACT… it is backed up by the reports from both diabetics and non-diabetics that adopt these diets that they feel like they are almost bursting with energy… well this is almost quite literally true… the now released fatty acids from their fat cells provide so much energy to them, that they can reduce caloric intake without feeling hungry (the body doesn't send hunger signals when it is bathing in energy) and they also have enough energy and reduced lethargy to exercise.

          You AGAIN are assuming that the equation is one way… I can't explain it any easier… go read up about it.

          The storage of energy from the diet as fat (due to hugh insulin) traps this energy, making it unavailable for use, and hence increases appetite or reduces energy expenditure. Either way the result is less movement with weight gain, or more eating with even more weight gain, most often BOTH.

          You then observe this and state it is the eating and reduced movement that causes fat storage, instead of realising that it can also be the fat storage that causes increased eating and reduced movement – IT WORKS BOTH WAYS.

          Yes it is true some people eat too much, but again, biochemically, eating carbs increases your chances of an insulin spike and then crash, which makes you more likely to feel hunger again. Again this is born out in studies and from real life experience.

          Eat a pasta meal for and you are SURE to be hungry when you wake up (sometime even before bed).

          Eat a protein and fat meal and you can even skip the next meal if you want. Repeated studies show satiety with proteins and fats FAR outstrips carbs, especially calorie for calorie.

          So whilst this is true, it doesn't mean it is the ONLY truth.

          "Type 2 diabetes is typically reversible with calorie restriction (a balanced diet) and/or exercise"

          It is also reversible with a reduction of carbs by eliminating grains (still eating veg and lower carb fruits) and/or exercise. And it doesn't result in hunger, and the foods are generally more enjoyable to eat.

          This I have witnessed with my own eyes. The second approach which is diets #4 and #5 (in my previous post) are much better than #3 – which is what you advocate.

          You have NEVER tried it, let alone understand it, yet you reject it.

          Spend some time reading through this site – you will see this is NOT a no carb site.

          The point is we don't need to eat as many carbs as is typically done (even without going into ketosis) – and this is backed up by science.

          Luke wrote on May 31st, 2011
      • Actually, after reading and thinking about this article more, I’m in agreement. And yes, I mistakenly jumped to some conclusions. He doesn’t say no carbs.

        However, I still have a problem with some of the author’s comments, which are reasons why I first posted:

        “… and the brain can run just fine (maybe even optimally) on a blend of ketones and minimal glucose. . . Entire civilizations have existed for ages on what is practically a zero-carb diet.”

        I don’t think it’s correct, and I would like to find sources that back this up.

        Seth wrote on May 31st, 2011
        • Seth,

          I have to acknowledge 2 things:

          1) You are a better man than most. May people argue their position, and wont budge, no matter what the evidence. Even more so for people that post on blogs etc… Have to say well done mate (and please do not take that as patronising, I sincerely mean it).

          2) I was a bit of a dick last night (well last night as far as the time zone I am in). I have been travelling for work, and was jet lagged, and clearly in a foul mood.

          This does not excuse some of the things I said in debating you, in particular the amount of ad hominem statements I made… poor form on my part and intellectually weak…. Argue the points/topic, don’t attack the person, I apologise for my snide remarks – no excuse.

          Regarding your remaining doubts about the following statement:

          “… and the brain can run just fine (maybe even optimally) on a blend of ketones and minimal glucose. . . Entire civilizations have existed for ages on what is practically a zero-carb diet.”

          Again I do not have references on hand, however a few things:

          1) Civilisations have existed for ages on what is practically a zero-carb diet. Inuits, various tribes, and significant portion of our entire species during the ice ages. This is documented.

          2) “and the brain can run just fine (maybe even optimally) on a blend of ketones and minimal glucose…”

          Again, there are sources to back that the brain can run just fine on a blend of ketones and minimal glucose… the key here being the use of the word minimal… minimal is definitely above zero, probably around 80-100g of carbs per day, but not much more than around 150g carbs per day for MOST people (naturally exceptions are always present). This is significantly less than what the typical diet would consume, especially if you eat wheat, corn or rice products. I would encourage you to do a search using the search function on this site. Mark will likely have a post specifically on carbs, and he will cite references many times. This post was a summary of a number of different concepts he has written about over many years.

          This leaves “(maybe even optimally)”… This is Mark’s view. He does not the brain DOES run optimally, he states it MAY run optimally. MAY is the universal qualifier. Whenever you see it, you can safely assume there is no specific evidence to be cited. It does not mean it doesn’t exist, it just means it isn’t being used.

          This is a problem when you read/hear/watch most news bulletins these days, to avoid doing REAL journalistic investigation, they just say “may”, “perhaps”, “suspected”… all these words allow you to say what ever you want, without a shred of evidence.

          “We may all die tomorrow”… UNLIKELY, but logically true, as we MAY all die tomorrow, no way of knowing.

          “X X may run for President”… again – 100% true, no matter how likely.

          If I wasn’t travelling I’d take the time to find some evidence, as I am certain I have read it somewhere.

          You may ask, but you defend this dietary approach, how come you are unsure?

          Simple – For all the biochemical and evolutionary reasons I have stated, and results I have witnessed with my own eyes, I know the elimination of carbs from grains and increased consumption of fats is NOT the health issue many state.

          I also know you can function on reduced carb consumption, both physically and mentally.

          To me, whether you perform better, is irrelevant. Likewise, even if it isn’t perfect, I know it works.

          However finally, I am a fanatic when it comes to the power of evolutionary pressures, and quite simply when you apply evolution to the problem, the fact remains, that as a species we MUST do at least as well, if not better with very low carb consumption, because until we learnt how to mill wheat, rice and corn and then COOK it (which was only ~ 10,000 years ago), the VAST majority of the human race just DID NOT HAVE access to that many carbs and so without having a choice, lived a VERY low carb diet. Add the selection pressures of an ice age (when the ability to survive on near zero carbs would have been selected for) and also the “thought experiment” I described about how the switching from high to low carb results in a lag in switching back to a low carb system SUPPORTS the fact we evolved not having ready access to lots of carbs (otherwise that lag would have been selected out) then I just cannot see how we CANNOT thrive on a low carb diet – evolution has selected us for that, and biochemistry provides all the proof to show fat is the preferred fuel source.

          And finally (there is always a finally) – our vast ability to store fat (actually I missed this in Mark’s post above, I independently came to the same conclusion as he has), and PALTRY ability to store carbs. If carbs are SO important for optimal function we would have evolved to preferentially store them – NOT fat.

          Anyway – all I can suggest is you explore this site more. As I said search for certain topics for more in depth posts (and perhaps use the menu system on the top to find topics).

          All the best with the exploration…

          Luke wrote on June 1st, 2011
        • Regarding your statement, “If carbs are SO important for optimal function we would have evolved to preferentially store them – NOT fat.”

          I can understand why one would believe this to be evidence for preferential use of fat by the body. However, it’s misleading. The reason animals have evolved to store calories in the form of fat is because adipose (fat) contains very little water compared to stores of glucose (glycogen). For every gram of glycogen, there’s something on the order of 3-4 grams of water with it. We evolved to store energy as fat simply because it’s a very efficient calorie storage mechanism. This mechanism allows animals to not have to carry heavy stores of energy. And it follows that there’s a relatively large amount of energy that is released when these long hydrocarbon chains are oxidized. I don’t think it’s accurate to say that energy is stored as fat because the body prefers to utilize fat. I think it would be more accurate to say that the body utilizes relatively large amounts of fat at REST because the demands for energy are less (creating time for the enzymatic events in beta oxidation, the krebs cycle, and oxidative phosphorylation). Although large amounts of energy are released, due to the efficient storage of this energy, it’s sluggish compared to glycolysis. I just can’t make an argument that the body prefers fat, mainly because the brain does not utilize fat. Most physiological processes in the body (e.g., cardiovascular, metabolic, etc.) function so as to serve the brain first.

          Seth wrote on June 1st, 2011
        • So far, the data doesn’t support this.

          Br J Nutr. 2010 Dec;104(11):1666-87. Epub 2010 Sep 23.

          Estimated macronutrient and fatty acid intakes from an East African Paleolithic diet.

          http://www.ncbi.nlm.nih.gov/pubmed/20860883

          “We found (range of medians in en%) intakes of moderate-to-high protein (25-29), moderate-to-high fat (30-39) and moderate carbohydrates (39-40).”

          Seth wrote on June 1st, 2011
        • Furthermore, why would the contents of human milk (1.1% protein, 4.2% fat, 7.0% lactose) be so different?

          Seth wrote on June 1st, 2011
        • I agree that our primitive ancestors probably consumed less carbohydrate than modern Americans, for example. And I also agree that our primitive ancestors, and modern humans, prefer fats over carbohydrate (I also agree that a ketogenic diet my be healthy in some respects for the brain, based on some interesting research articles I read today). However, our best estimates of a primitive diet does not reflect fat intake exceeding carbohydrate intake. If carbohydrate were limited to what is suggested here, and according to what you say (“minimal is definitely above zero, probably around 80-100g of carbs per day, but not much more than around 150g carbs per day for MOST people”) the rest of the daily requirements just for resting metabolic function (1600 kcal, for example) would have to be made up in large proportion in fat and protein. 100 grams of carbohydrate is only 400 kcal. Healthy, daily activity would about double the required calorie intake. This paradigm (100-150 grams carbo) seems to be okay just to meet resting metabolic needs (or to lose weight), but remember that our primitive ancestors were also distance runners! There’s has to be room for calorie intake for physical activity.

          The research article below suggests that protein intake often takes place of carbohydrate intake in hunter-gather diets, but that the proportion of fat or protein intake probably doesn’t exceed carbohydrate intake.

          Am J Clin Nutr. 2000 Mar;71(3):682-92.

          http://www.ncbi.nlm.nih.gov/pubmed/10702160

          Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets.

          “This high reliance on animal-based foods coupled with the relatively low carbohydrate content of wild plant foods produces universally characteristic macronutrient consumption ratios in which protein is elevated (19-35% of energy) at the expense of carbohydrates (22-40% of energy).”

          Seth wrote on June 1st, 2011
        • Okay, I’m more in agreement now, considering the research article below:

          Am J Clin Nutr. 2000 Mar;71(3):682-92.

          Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets.

          http://www.ncbi.nlm.nih.gov/pubmed/10702160

          “Our macronutrient projections for worldwide hunter-gatherer diets indicate that these diets would be extremely high in protein (19–35% of energy) and low in carbohydrate (22–40% of energy) by normal Western standards, whereas the fat intake would be comparable or higher (28–58% of energy) than values currently consumed in modern, industrialized societies.”

          Seth wrote on June 1st, 2011
      • “However I assume you mean a text for physiology, as in biochemistry texts, all the basic information is already there!!!”

        All the information is there, and then they simply ignore that information to express assumptions which are contra-indicated by their own data. (Paraphrase) “Insulin controls the level of blood glucose by opening the transport proteins which leads to the glucose binding to fatty acids which cannot leave unless glucagon releases the glucose from the cell. But obesity is actually caused by eating a poor diet and not exercising enough.” It’s like a disconnect between their information and their ability to think, probably caused by having heard the lie so often. I have marked this kind of false interpretation of the data in my Physiology books, my basic biology book, and even in both psychology books so far. It was presented without the biochemical info in my last math book and I know I am going to run into it in my “Human Ecology” class. I even had to sit through my language instructor’s lecture about it, as if it had anything to do with APA citation guidlines.

        The facts are all there (as in Mark’s article), but many people simply cannot see them because their assumptions are smack in the way.

        Bill DeWitt wrote on May 31st, 2011
        • Hey Bill,

          Yeah you are right… I likely have forgotten the finer details like the throw away comments… I will admit it was some time ago I was at Uni.

          Good luck with the studies and as I said, I look forward to reading Biochemistry Essentials by B. DeWitt!!! :-)

          Luke wrote on June 1st, 2011

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