Keto Diarrhea: Causes and Remedies

When you go Keto, digestive changes often follow. Sometimes these changes are positive, but sometimes you end up with Keto diarrhea or Keto constipation.

This can be frustrating. The Keto diet is challenging enough without the GI symptoms.

But there’s good news. These digestive issues usually have specific causes that can be understood, addressed, and remedied. 

What causes Keto diarrhea, how can you fix it, and how does Keto affect gut health generally? Keep reading. 

What Is Diarrhea?

Diarrhea is defined as having three or more watery or loose stools per day.[*] That’s the medical definition, but most people aren’t tallying their trips to the bathroom. You know it when you have it. 

Bacteria (like E. coli) or viruses (like norovirus) are the most obvious causes of diarrhea. But diarrhea can also be driven by food sensitivities, chronic gut conditions (like IBD), digestive enzyme insufficiency, or gut bacteria imbalances. 

Many of these causes relate to Keto diarrhea. 

Potential Causes of Keto Diarrhea

Problems with Keto and diarrhea? Here are some possible reasons why:

#1: Food intolerances or sensitivities

Going Keto means new foods are likely on the menu. Unfortunately, you might be sensitive to some of these foods.  

Food sensitivities are an underappreciated cause of GI symptoms on Keto, Paleo, or any other diet. An example will help illustrate. 

Let’s assume that avocados are giving you trouble. You might be sensitive to the soluble fiber, the high histamine content[*], or something else about this nutritious food. 

And every time you suffer through symptoms, it likely drives more gut inflammation.[*] (Inflammation means unnecessary immune activity). This inflammation can cause abdominal discomfort and loose stools. It can also further damage the gut, creating even more food intolerances. 

Don’t despair. Avoid the food, let the gut rest, and perhaps reintroduce it later. 

#2: Gut microbiome shifts

When you change your diet, you change the composition of your gut microbiome. This vast colony of bacteria, yeast, and other microbes plays a crucial role in regulating digestion—so shifting it à la Keto may have consequences. 

Often the consequences are good. Carbohydrate restriction may be an effective treatment for chronic diarrhea and IBS, among other gut symptoms.[*] When you limit carbs, you limit the favorite foods of pathogenic gut bugs. 

However, for some folks, Keto may shift things in the wrong direction. Everyone’s gut is different.

#3: Too much fiber

A sage piece of Keto wisdom is to load up on non-starchy vegetables like spinach, kale, and broccoli. These superfoods are rich in vitamins, minerals, and—yes—fiber. 

For folks with chronic gut issues (IBS, IBD, etc.), too much fiber can exacerbate diarrhea. Low-fiber diets, however, may help  to reduce symptoms in folks with IBS.[*] 

#4: Problems digesting fat

Not everyone digests fat with ease. Some people, for instance, are deficient in the pancreatic enzyme lipase—and this deficiency can cause fat-malabsorption and diarrhea in the context of a high-fat Keto diet.[*] These people may still benefit from a ketogenic or low carbohydrate diet with a focus on fiber, low-to-moderate fat intake, and a higher protein intake.

Also, all coconut-based fats are notorious laxatives. Just a tablespoon of MCT oil or coconut oil can send some people running to the bathroom. 

The trick is to go slowly. Start with a teaspoon of MCT oil and work your way up from there. 

#5: Too much magnesium

Taking too much magnesium can also have a laxative effect. This is especially true of magnesium oxide, a poorly absorbed form of this mineral. Try magnesium citrate, magnesium glycinate, or magnesium malate for more gut-friendly forms of this mineral. 

How Else Might Keto Affect Digestion?

The most common digestive complaint on Keto isn’t diarrhea. It’s constipation. 

Keto constipation can occur due to:

• Improper hydration (dehydration dries out stool)
• Insufficient dietary fiber
• Too much dietary or supplemental calcium
• Gut microbiome shifts

In general, reducing carbs tends to starve gut bacteria and reduce the amount of bulk moving through the gut. This may cause constipation in some but prevent diarrhea in others.  

In one small study, people with IBS experienced significant diarrhea relief after 4 weeks of Keto dieting.[*] Other research has found similarly promising results for various low-carb or low-fiber interventions.[*]

The bottom line? How Keto impacts gut health is highly individual.

4 Strategies to Help With Keto Diarrhea

If you’re struggling with GI symptoms on Keto, consider these tips. 

#1: Avoid problem foods

If a food provokes symptoms, avoid that food. It’s that simple. 

Sometimes, it’s hard to ascertain which food is causing the problem. If that’s the case, consider a couple of strategies. 

First, keep a food journal. This will let you correlate specific foods with specific symptoms. (Tip: you can automate much of this by logging meals in the Carb Manager app). Food journals are one of the first ways that a dietician or physician would assess your potential food intolerances.

If the food journal isn’t working, consider an elimination diet. Eliminate all potential problem foods—eggs, soy, dairy, nuts, etc.—then slowly reintroduce them one at a time to gauge your reaction. 

Elimination diets may feel restrictive but your intestinal comfort is worth the temporary sacrifice. 

#2: Be careful with fiber

For most people, fiber isn’t a problem. More fiber tends to be better for digestion, metabolic health, heart health, and many other aspects of wellbeing.[*] High fiber foods can even help lower your risk of certain cancers.[*]

But if you have diarrhea, ratchet down your fiber intake and see what happens. Less fiber means less food for pathogenic gut bacteria that may be driving your issues. 

#3: Take probiotics

Probiotics are supplemental microbes that can help:

• Reduce inflammation[*]
• Strengthen the integrity of the gut barrier[*]
• Fight gut pathogens[*]

Consuming probiotics may also help with both acute and chronic diarrhea.[*] 

If you have diarrhea, you may want to consider both probiotic supplements and fermented foods like sauerkraut. Both contain beneficial organisms to help balance your microbiome. 

#4: Allow time

For most of us, adapting to the Keto diet doesn’t happen overnight. That includes digestive adaptation.  

You may need time, for example, to ramp up the production of digestive enzymes. (Note: if that doesn’t work, you can also supplement with digestive enzymes). 

Your gut microbiome also needs time. It’s a living ecosystem, not a smartphone. It takes more than ten minutes to update. 

So be patient. Give Keto a week or two, and follow the other tips in the article. It may require some trial and error, but keep at it or consider working with a knowledgeable practitioner if you need further support. 

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