Keto Poop: How This Low-Carb Diet Can Change Your Stool
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3 Ways Low-Carb Diets Like Keto Can Change Your Poop (and When to Worry)

3 Ways Low-Carb Diets Like Keto Can Change Your Poop (and When to Worry)
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Updated on July 31, 2025
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Your bowel movements are closely related to the foods you eat — and don't eat — which is why the keto diet can disrupt your usual restroom routine. Read on for three ways keto can change your poop and what that means for your health.

1. Keto Constipation

If you're someone who has lived most of their life enjoying a variety of fruits and whole grains, you probably also enjoyed the luxury (yes, it's a luxury) of regular digestion. But once you banish these carbs from your diet, your fiber intake takes a big hit, too, according to Niket Sonpal, MD, a New York City-based internist and gastroenterologist.

Fiber is the nutrient responsible for keeping your poops consistent. To maintain regularity, you should aim to eat about 28 grams of fiber per day, based on an intake of 2,000 calories per day.

When you cut carbs, you also cut a lot of key fiber sources, like whole grains, fruits, and legumes. If you adopt a low-carb, high-fat, and high-protein diet, don't be surprised if you see a reduced number of bowel movements each week, Dr. Sonpal says.

You can combat these effects by eating more high-fiber, low-carb foods, like avocados (about 10 grams of fiber per cup) or raspberries (about 8 grams per cup).

When to worry:‌ If you’re having only three bowel movements per week, you should probably consult your doctor, says Sonpal, especially if your movements were more frequent before you began the diet.

Ketogenic food concept - plate with keto food
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2. Keto Diarrhea

On the opposite end of the spectrum, some people might experience bouts of diarrhea after starting a low-carb, high-fat diet, Sonpal says. "This happens when the body doesn't digest all the fat that it is consuming, leading to an upset stomach,” he says.

Chronic diarrhea may also be a sign of steatorrhea, which is when there is too much fat in your stool. Steatorrhea is a sign of malabsorption, which happens when your body doesn't break down or absorb the foods and nutrients you consume. Over time, this can lead to nutrient deficiency or dehydration.

A variety of factors can cause steatorrhea, but if you only began experiencing symptoms after dramatically shifting your diet, it's probably the reason you're experiencing diarrhea.

‌When to worry:‌ Typically, keto diarrhea is temporary and can be avoided by introducing the diet slowly. But if these symptoms persist longer than a few days, it's probably best to consult your doctor and revert back to your usual eating habits.

3. Keto and Yellow (or Smelly) Poop

Yellow or particularly smelly poop is another side effect you may experience after taking on a low-carb, high-fat, high-protein diet. As with symptoms of diarrhea, your stool can become yellow and smell foul due to excess fat.

While yellow or foul-smelling poop isn't dangerous per se, it does indicate that your intestines aren't absorbing enough nutrients or your liver isn't producing enough bile to break down the fat in your diet.

When to worry:‌ If your poop doesn't return to a normal color after a few days, it's a good idea to consult your doctor.

What Does This Mean for Your Diet?

While the keto diet can help you lose weight, it may not be the best diet for your body if you're experiencing problematic digestion. "It may be helpful in losing stubborn weight, but it may be dangerous if you have a chronic condition like IBS," Sonpal says.

The Takeaway

  • The keto diet is high in fat, moderate in protein, and low in carbohydrates. It can potentially result in digestive problems, such as constipation, diarrhea, and yellow or smelly stools.
  • One reason for digestive issues on keto is cutting back drastically on fiber, which is found in whole grains, fruits, and legumes.
  • If you experience digestive issues on keto, consult your doctor, who can suggest other weight loss plans that might be better for you.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Dietary Fiber. U.S. Food and Drug Administration.
  2. Avocado, raw, all commercial varieties. USDA FoodData Central.
  3. Raspberries. USDA FoodData Central.
  4. Malabsorption. International Foundation for Gastrointestinal Disorders.
  5. Stool Color: When to Worry. Mayo Clinic. October 10, 2024.
  6. Fecal Fat. University of Rochester Medical Center.
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Lynn Grieger, RDN, CDCES

Medical Reviewer

Lynn Grieger is a registered dietitian-nutritionist, certified diabetes care and education specialist, certified personal trainer, and certified health and wellness coach. She completed requirements to become a registered dietitian at Valparaiso University in 1987 and completed a dietetic internship at Ingalls Memorial Hospital in Harvey, Illinois, in 1988. 

Lynn brings her expertise in nutrition, exercise, and behavior change to her work in helping people reach their individual health and fitness goals. In addition to writing for Everyday Health, she has also written for websites and publications like Food and Health Communications, Today's Dietitian, iVillage.com, and Rodale Press. She has a passion for healthy, nutrient-dense, great-tasting food and for being outdoors as much as possible — she can often be found running or hiking, and has completed a marathon in every state.

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Bojana Galic is a NASM-certified personal trainer and a staff writer for everydayhealth.com covering fitness, sports nutrition and health. She is a 2018 graduate of the Arthur L. Carter Journalism Institute at New York University.

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