Meet Mark

Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...

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Keto Side Effects: What’s Real, What’s Not, and What Helps

With more people enthusiastic about the ketogenic diet comes more talk about potential adverse side effects. Upon closer examination, almost all of the complaints can be traced to a flawed approach. Granted, if you are coming to the game with significant metabolic damage from decades of carbohydrate dependency, or not paying attention to some common sense best practices, such as choosing healthy foods instead of blindly focusing on macros, you will likely struggle with something as stringent as keto.

Let’s cover some of the common keto complaints being bantered about these days, examine what’s really going on, and discuss strategy for how to avoid any adverse side effects to going keto.

Keto Flu

The keto flu refers to feelings of general malaise and even immune disturbances in association with dietary modification. Commonly cited symptoms include feeling lethargic (especially in the afternoon), feeling hot, feeling achy in joints and muscles, among other related sensations.

Here are eight important tips for avoiding the keto flu. Check out the full post for further details.

  1. Get sufficient omega-3s, from oily, cold water fish or supplementation.
  2. Consume an extra five grams (1 teaspoon) of sea salt or Himalayan pink salt per day when going keto.
  3. Consume foods rich in potassium and magnesium. Avocado is an excellent high fat, low carb source for both.
  4. Make an extra effort to hydrate strategically, especially around workouts.
  5. Consume more healthy, natural fats to replace the carbs you are cutting out.
  6. Consume MCT oil (from coconut oil or MCT oil supplements) to stimulate external ketone production.
  7. Move frequently and conduct cardio sessions at low heart rates.
  8. Try a gradual reduction in carbs if an abrubt reduction seems problematic or you experience keto flu symptoms.

Finally, wait it out. Certain folks who do everything by the book and follow every bit of good advice may still get a few symptoms of the keto flu. This usually comes in the initial three weeks of entering nutritional ketosis, and things get much better very quickly. Trust that your lull will pass and your energy will increase substantially—usually within a few days.

Keto Poop

Someone asked me this the other day on a podcast: What’s the deal with keto poop? A disconcerting number of people on keto diets appear to be having trouble with their poop—or lack thereof.

The biggest issue is that some people consider keto to be a free pass to skip the green stuff. Either that, or they assume “vegetable=carb” and avoid them. Without plants, it’s tough to eat enough fiber, especially the fermentable, prebiotic kind that sustains our gut bacteria. We don’t need bowel-rending quantities of fiber. We shouldn’t take pride in the ability to fill the toilet bowl with perfect coils of crucifer corpses. These are unnecessary at best and downright harmful at worst.

But we still have to feed our gut bacteria. We still have to poop. We don’t want to strain and come up empty. Humans are industrious apes; we like to produce, not work in vain.

What else is going on, besides the lack of fiber?

You may need more water. Going keto causes an initial reduction in fluid retention in cells throughout your body. Your digestive tract requires water to keep the fecal matter soft and moist. As you aspire to consume more fluid, be sure to add a pinch of salt to each cup of water you drink, and to sip steadily throughout the day instead of binge chugging. These measures will help you better absorb additional fluids instead of excrete them.

Take magnesium. Magnesium helps regulate gut motility, and magnesium deficiencies are a common cause of constipation. Magnesium needs tend to rise on keto as well. Some experts recommend taking 400 mg in supplemental magnesium per day when going keto.

Take resistant starch. A starch that acts like fiber, RS is one of the most potent prebiotic substances around. Raw potato starch is an easy, dependable source of RS. Start slow with a teaspoon into your smoothie or full-fat yogurt; work up to at least a tablespoon per day.

Keto Body Odor

The literature on diet and body odor is pretty thin.

In 2006, Czech researchers placed men on either a diet containing red meat or one without red meat, then had them sweat. Women smelled and rated the sweat. Across the board, the red meat dieters produced less attractive body odor. When they had everyone switch to the other diet, the results persisted: Those who had switched to a no-red meat diet produced better-smelling sweat.

It sounds damning, but before you stop eating beef and lamb, check out the details. The non-red meat diet differed from the red meat diet in many ways. The non-red meat dieters weren’t just avoiding red meat; they also ate way more fruits, vegetables, eggs, cheese, and soy than the meat eaters. The researchers failed to control all other aspects of the diet, instead focusing only on the meat.

I’ve said many times before that keto dieters tend to eat less produce, either because they don’t like it and see keto as a free pass for near-carnivory, they worry about the carbs in produce throwing them out of ketosis, or they somehow think plants are restricted on keto. These are mistakes. Common ones. You can eat plenty of produce on keto. You should eat plenty of produce on keto. Mushrooms of all kinds. Leafy greens. Cruciferous veggies like broccoli, cauliflower, bok choy. Low-carb fruits like berries. Anything fibrous.

A more recent study seems to confirm my suspicions. Both produce and meat, cheese, and egg consumption predicted better-smelling body odor. You know what predicted worse body odor? High carbohydrate intakes.

I haven’t seen any legit reasons why a keto diet in particular would increase body odor. Try eating more plants and reassess in a week.

Keto Breath

Yes, ketone breath is a common indicator of ketosis, as numerous studies confirm. (1,2,3) In fact, researchers have found that breath acetone predicts the rate of fat loss in humans. More acetone, more fat loss.

In reality, it’s a different smell than most are used to, but not necessarily bad—a slightly sweet scent. Given that our modern, grain-based diet is much more physiologically novel than a well-designed, plant-inclusive keto diet would be, ketosis breath might actually be much more “normal” than we imagine.

You can accept it, particularly if you’re not necessarily bothered by the different scent. As your body becomes more keto-adapted, it becomes more efficient with ketone burning, and the smell might well diminish.

But if you’re looking for ways to mask it in the meantime, practice good oral hygiene, invest in probiotic foods and supplements (to make sure there’s no underlying gut issues contributing to the problem), and consider a xylitol-sweetened chewing gum.

“Deflated” Muscles

When your glycogen stores are topped off and your muscles are full of water—each gram of glycogen is stored with 3-4 grams of water—they’re bigger. More pronounced. Fuller. Going keto, which depletes muscle glycogen and reduces fluid retention, can give your muscles a “flat” or “deflated” appearance.

You can accept it for the time being. As time goes on and your body calibrates itself to the new metabolic pathway, you won’t shed as much water. Your muscles will return to normal.

You can work carbs into your diet before, during, or after hard training sessions. Anything intense enough and long enough to burn through muscle glycogen allows carb consumption without knocking you out of ketosis.

You can try creatine. Creatine is also stored in the muscle alongside water, so it may increase muscle fullness. Creatine also has the benefit of increasing muscle phosphocreatine energy stores, which we use for quick movements and brief feats of strength.

Low Energy

Some people just won’t do as well as others on a ketogenic diet. In particular, high energy demand athletes often choose to consume more nutritious carbs than advised per keto guidelines. Females with metabolic damage from a history of yo-yo dieting, or thyroid or adrenal dysfunction, also report difficulty with prolonged carb restriction to promote keto.

Again, with an optimized approach, things might come out great for virtually everyone who tries keto. Realize that since going keto opens up an entirely new energy pathway without limiting your ability to access the previous pathway, low energy is actually a pretty rare complaint. If it crops up with you, here are some things to watch out for:

Chronic exercise patterns: Fat-based metabolisms are great for long, slow movement, quick bursts of speed with rest in between, and feats of explosive strength. In other words, making your way through the world, doing some strength training, going for hikes, playing with kids, running some sprints, and are all tenable on keto. Heavy CrossFit training or anything else that burns a lot of glycogen at a lot of workouts each week, however, might pose issues. Resolve this by either scaling back the training or eating some carbs before, during, or after your workouts.

Inadequate calories: Keto’s satiating qualities are a double-edged blade. They help us eat less and lose body fat without really even trying, but they can also sometimes lead us to eat too little. This can cause a reaction in your body to slow down metabolic function and make you feel generally less energetic at rest. One solution is to cycle periods of generally increased caloric intake, and increased intake of nutritious carbs by default. This suggestion is totally different from the suggestion to engage in purposeful carb refeeds, where you binge on nutrient-devoid carbs in the name of a cheat day. This is never advised for any reason.

Unrealistic expectations: If you’re five days into your keto experiment and about to give up because you yawned after lunch, have a little patience. Things take time to change.

Hair Loss

The diet’s going great, you’re dropping inches, you have good energy levels, increased clarity of mind, but every time you take a shower or brush your hair or join a gorilla grooming circle, you’re losing hair. What gives?

You’ve lost weight. By far the most common cause of unexplained hair loss is simply rapid weight loss or dietary change. This disrupts the normal growth and decline cycle of your hair follicles, shunting a greater proportion of them into the “rest” phase to be pushed out by incoming hairs. Even though you may see extra hair in the shower or on the brush, your actual hair thickness shouldn’t change much.

Check your thyroid. As I wrote in a previous post, certain incarnations of keto (high in omega-6, low in supportive nutrients like selenium and iodine) can lower T3 levels, and this can cause premature hair loss.

High Cholesterol

The doc hands over the printout.

Last week, he’d expressed major skepticism over your new diet. “Sure, you’re losing weight, but let’s see what it’s doing to your arteries.” Today, you already know. His smirk says it all.

“You’ve got high cholesterol.” He’s beaming. Why the hell is he so happy?

It’s a fairly common scene for new keto dieters. Aubrey Marcus recently referenced a highly-disturbing stat that 25% of physicians still equate consuming dietary cholesterol with increased blood cholesterol, an association that has been unequivocally refuted by recent science. But before you accept AHA-sanctioned diet advice, determine if there’s actually a problem.

Check your ratios. Total cholesterol/HDL ratio is a good indicator of how long LDL is hanging around in the blood and remains the best standard assessment of heart disease risk. Another good one is triglyceride/HDL ratio, which is a strong surrogate marker for insulin resistance. In both cases, lower is better. An ideal T/HDL ratio is 1:1. I’d say 2:1 is about as high as you want to go. An ideal TC/HDL ratio is 3.5:1 or lower.

Stop grazing. Allowing time to pass in between meals, or getting crazy and deciding to skip a meal or two, has been shown to improve cholesterol numbers.

Don’t gorge on fat. Remember that the best things happen when you’re consuming your own body fat. You don’t need to melt a stick of butter in your coffee every morning to keep your membership in the keto club.

Balance your fat. Saturated fat has received a terrible rap in the literature, but that doesn’t mean it’s the only fat you should consume. Look to the fatty acid ratios of ruminants like beef and lamb—or your own adipose tissue—for guidance. They have about equal amounts of saturated and monounsaturated fat with a small amount of PUFA. Mix up the butter and cream with olive oil and avocado oil.

Give it time. Your body’s still adjusting to the new energy pathway. Give it a few more weeks before you worry (and even then, don’t worry too much).

Those are six of the most commonly cited adverse side effects of going keto. As you can see, sometimes they’re real and you need to make changes, sometimes they’re a misinterpretation and you need to look more closely, and sometimes the best response is to relax and let the process take care of itself.

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