Why Can't Some People Do Keto?

a keto-friendly meal of fish, avocado, and vegetables

Not everyone can obey such a strict diet, but millions wouldn’t at least try unless they felt it was worth the effort and the potentially positive results.

Research suggests that the popular diet known for rapid weight loss also could benefit those with cancer, diabetes, epilepsy, and cardiovascular concerns. It can help with digestion, too, but some people find that the keto diet worsens their digestive issues. Let’s explore why, and see if anything can be done to prevent this from occurring.

Keto Basics

The diet’s whole-food meals of roughly 75 percent of calories from fats, 20 percent from protein, and 5 percent from carbohydrates rely on fuel mainly from steadier-burning fats versus the rollercoaster ride from sugar. That’s good news for weight loss. “Lowering carbs in general also reduces the fermentable ones that bad gut bacteria feast on. This can reduce and prevent gas and bloating,” says Michael Smith, ND, BHSC, of Planet Naturopath, in Victoria, British Columbia, Canada.

“Keto can be a great diet for some. But to make the most of it, your fat digestion has to be optimal,” explains Ann Louise Gittleman, PhD, CNS, New York Times bestselling author of Radical Metabolism.

What Can Go Wrong on Keto?

Problems Digesting Fats

Restricting carbs forces the body to use ketones for energy. The liver makes these chemical compounds as it breaks down fat with the help of bile, sending any excess bile to the gallbladder for storage.

“If you have congested bile from blocked ducts, too little bile, fatty liver disease, or other digestive issues, or your gallbladder has been surgically removed, then you can’t digest all the fats the keto diet requires you to eat,” continues Dr. Gittleman.

To support fat digestion, she recommends the lipotropic nutrients choline, inositol, and methionine, all of which help break down and speed up the removal of fat from the liver. She also recommends taking beetroot and bile salt supplements to make it easier to absorb and digest fats.

Nutritional Imbalances

The keto diet also can fail you when its carb restrictions make you overdo it on taste-treat alternatives. That’s when you spend most of your fat and protein allowance on bacon, hamburgers, cheese, and butter and don’t eat enough healthy proteins and fiber, green leafy vegetables, and other plants rich in nutrients.

“Too much animal fat and too little fiber cause diarrhea,” Dr. Smith says. This is also true with an excess of MCT [medium-chain triglycerides] oil, which is found in coconut oil and as a partially human-made oil by itself. “And too much cheese brings on constipation. Not enough water will do that, too, particularly in the early stages,” Dr. Smith continues.

The "Keto Flu"

“The first weight you lose on a ketogenic diet is water weight,” says Dr. Gittleman. “At first, you feel good and the weight loss is a morale-booster. But the flushing causes the toxins to concentrate, giving you the ‘keto flu,’ with symptoms from digestive upset and skin rashes to headaches and body aches.” Good thing it lasts only a few days.

How to Succeed on Keto

  • Stay Hydrated

    Drink plenty of water while on the keto diet. But since you’ll urinate more, you’ll lose crucial electrolytes, so be sure to boost those with bone broth, which also supports healthy gut bacteria.

  • Avoid Temptation

    Keep only keto-diet ingredients in your home, carefully plan all your meals, study restaurant menus before you go, inform loved ones, don’t go to parties too hungry, and keep track of everything you eat. And forget cheat days.

  • Check with Your Healthcare Practitioner

    Your favorite movie star may rave about the keto diet, but like any health routine, you want to make sure it’s the right one for you.

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Personal communication: Ann Louise Gittleman, Michael Smith, 7/19


Claire Sykes

Claire Sykes is a freelance writer based in Portland, Oregon.

She loves that she's always learning about something new, and gets to talk with a wide variety of people, often at such an extent or depth.