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July 9, 2022

Ketosis Poop: Color & Smell | Low Carb Green, Yellow, Dark, Black Stool

ketosis poop color smell low carb green yellow dark black stool

Ketosis Poop. What is it? What causes it?

The keto diet is popular these days. Many take to the diet to lose weight but it has other health benefits. There are side effects to the keto diet, however, and many of them involve the gastrointestinal tract. But, this is true anytime you change your diet.

One thing that can change the keto diet is your poop and poop habits. Poop – or at least – what’s in it, is a good indicator of your overall health. You can become constipated when on a keto diet. You can also have diarrhea. Your poop can smell – more poopy. Your poop can change colors.

Does Ketosis Make Your Poop Smell? What Does It Smell Like

Let’s start with the smell of poop. Not the most attractive smell, is it?  Individuals on a ketogenic diet frequently report a change in the smell of their poop. The reason for that is on a keto diet there is the consumption of a lot of high-fat foods which makes stool move more slowly through the gastrointestinal tract.  As stool sits in your system for long periods of time and it putrefies more easily and this is made even worse by the usual increase in protein consumed on a keto diet.

What Should My Ketosis Poop Smell Like?

Pick up some soft dirt or earth in your yard and smell it. Your poop should smell pretty close to that. If you cannot wait to get out of the bathroom after a bowel movement due to the stench of your poop, then is an indication of something amiss with your health – at least your gut health. If you eat a natural diet then the smell of your poop should smell natural like decomposing material in the earth or soil.


ketone smell in stool
smells like acetone


How Often Should You Poop?

This is very much individualized. What is important is there is a change in your usual bowel habits when on a keto diet?  Some people normally have 2 or even 3 bowel movements a day. Some have one bowel every 5 days. Normal is considered no fewer than a bowel movement every 3 days. The fiber in the diet, your activity level, medication, stress levels, and fluid intake will affect the number of bowel movements you have. Having fewer bowel movements as your remove carbohydrate on a keto diet is to be expected.

Another question is “how to poop”.  Squatting is a more natural and optimal position that facilitates having a bowel movement requiring less force and straining than sitting on a toilet.

Low Carb Poop Color: 4 Meanings

The color of poop will change when on a keto diet. But, let’s first talk about normal color.

Poop is normally brown. The color will fluctuate some based on what you ate and how much bile is in your stool. Bile is a fluid your liver makes and stores in the gall bladder to break down fats consumed in the diet. Bile is yellowish-green color. But as the pigments that give bile its color travel through your GI tract, they go through chemical changes and turn brown.

Now, what happens when on a low-carb diet or keto diet?

Keto Smelly Yellow Poop Color

Yellow poop especially that looks greasy and smells bad is likely related to the consumption of additional fat in a keto diet. Yellow poop could also mean that you are not absorbing enough nutrients or that your production of bile has decreased which would lead to less absorption of fat from the gut. Yellow poop should resolve in a few days. If it does not, then see your physician.

Keto Poop Green

On a keto diet, there will be a change in the bacterial flora of the colon related to the change in the content of meals eaten. Green stool in the absence of symptoms is not concerning. Also, although carbohydrate intake is limited on a keto diet, some individuals increase their consumption of green veggies (high in nutritional content) which can make poop green.

Ketois poop
Image courtesy of Pixabay

Keto Poop Color Dark Black

Foods and supplements that turn poop black include:

  • Black licorice
  • Blueberries
  • Iron supplements

Medicines that have bismuth subsalicylate (Kaopectate, Pepto-Bismol) can also cause very dark stools.

Other causes of black poop

Poop that looks like tar is often a sign of bleeding in the digestive tract. Some causes include:

  • Bleeding from stomach ulcers.
  • Bleeding sores in your esophageal acid reflux.
  • Bleeding from noncancerous tumors in the upper GI tract
  • Cancer

Keto Diarrhea

It will take time for your digestive system to adapt to a low carbohydrate and high-fat diet. Until this adaptation fully occurs you may experience diarrhea. The change in diet may lead to changes in mineral content in the diet and any change in diet can affect the gut flora leading to alterations in the consistency of a bowel movement.

Also, in the early transition from a standard diet to a keto diet water is lost. In addition, to more forceful urination, your stools may be more watery.

If you’re dieting low or high in certain electrolytes diarrhea can ensue. The electrolytes sodium, magnesium, and potassium are of particular importance to low-carb dieters as there’s a tendency for the body to eliminate them faster. Heavy exercise on a ketogenic diet can lead to critical mineral loss through sweating, urinating, and physical stress from working out.

Probiotics may help reduce the duration of diarrhea from a keto diet. Diarrhea on a keto diet is common and transitory.

Keto Constipation

Constipation is caused by loss of water in the early stages of ketosis as well as a tendency for there to be low fiber on a keto diet though that does not have to be the case. A low-carb, high-fat diet like keto lowers the gut flora or good bacteria in the gut that help to digest macronutrients. Constipation is more common when the level of gut flora is reduced.

The reduction in prebiotic fiber (indigestible plant fibers), and lack of fiber, in general, contribute to a constipated bowel.

If constipation occurs simply eat more high-quality leafy greens and cruciferous vegetables. High-fiber, low-carb foods include raspberries and avocados. Aim for 35 grams of fiber a day and 3 bowel movements a week as a minimum.

Should Keto Poop Burn?

Keto diarrhea can cause poop to burn. With diarrhea partially digested is moving through the intestinal tract more quickly and stomach acids and digestive enzymes may not be fully neutralized and which can cause anal burning.  Adding spices to your meals can also be a factor leading to burning poop. Keto diet disrupts normal gut flora and a change in flora can cause poop to burn until the GI tract adapts to the change in diet.

How to Stop Keto Poop

Can anything be done to avoid ketosis poop?  Yes, is the answer. Whether you are experiencing constipation or diarrhea on a keto diet there are steps you can take to avoid these two extremes. To avoid constipation be sure to work to drink plenty of water and add some high-fiber foods into the diet. This would include:

  • non-starchy vegetables, including greens, broccoli, asparagus, and cauliflower
  • nuts and seeds
  • avocados
  • chia and flax seeds
  • unsweetened coconut

To avoid diarrhea try these tricks:

  • Staying hydrated
  • Drink bone broth
  • Take electrolytes
  • Stay active

Bone broth is high in electrolytes and minerals.

There you have it. Probably more than you wanted to know about ketosis poop.


Related Articles:


What Does A Ketosis Urine Color Chart Mean?


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Dr. Joe Jacko

Dr. Joe is board certified in internal medicine and sports medicine with additional training in hormone replacement therapy and regenerative medicine. He has trained or practiced at leading institutions including the Hughston Clinic, Cooper Clinic, Steadman-Hawkins Clinic of the Carolinas, and Cenegenics. He currently practices in Columbus, Ohio at Grandview Primary Care. Read more about Dr. Joe Jacko

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