Got Keto Diarrhea? Here’s Why It Happens + 5 Ways To Stop It!


The keto diet, which is short for the ketogenic diet, is a high-fat diet that’s very low in carbohydrates and contains a moderate amount of protein. 

Most experts suggest that most ketogenic diets involve consuming 70–75% of your calories from fat, 20-25% of your calories from protein, and 5–10% of your calories from carbohydrates. 

This ratio is said to help shift the body into a state of ketosis, meaning that the body burns ketones for fuel. The keto diet has been shown to help support weight loss and improve insulin sensitivity, among other markers of health.

However, some people experience diarrhea on the keto diet. So, does keto cause diarrhea? What can you do to prevent keto diarrhea? Keep reading for our take on diarrhea and keto and what you can do to avoid it.

In this guide, we will cover: 

  • Does Keto Cause Diarrhea?
  • Diarrhea and Keto: Why Am I Getting Diarrhea On Keto?
  • How to Prevent Keto Diarrhea

Let’s jump in!

A person with keto diarrhea, doubled over in pain.

Does Keto Cause Diarrhea?

The keto doesn’t necessarily cause diarrhea, but experiencing diarrhea on the keto diet is fairly common.

Most people who experience diarrhea or gastrointestinal distress on the keto diet find that these symptoms subside after a couple of weeks on the diet.

As with all types of extreme dietary changes, when you switch to the keto diet, your body has to get used to digesting a totally different group of foods.

This can affect your stomach, intestines, and bowel habits. 

Some people continue to experience GI symptoms on the keto diet, including keto diarrhea, but your own digestive tract may be significantly or minimally impacted and may adjust quickly or may never fully adapt.

Diarrhea and Keto: Why Am I Getting Diarrhea On Keto?

There are several potential reasons why people experience diarrhea on the keto diet. The main causes of keto diarrhea can include all or some of the following:

The keto diet breakdown of carbs, fats and protein and a platter of food.

#1: The High Fat Content

The keto diet, by nature, is a high-fat diet. Some people’s bodies do not absorb fat particularly well, causing a greasy stool that is loose.

This is particularly common for people who have had their gallbladder removed or who otherwise do not produce a lot of bile, which is necessary for fat absorption.

Additionally, bile is a natural laxative. Because the liver has to produce extra bile on the keto diet in order to break down all of the fat that is being consumed, the partially-digested content in the intestines, containing the bile mixed with the fatty ingested food, travels through the intestines into the colon and bowels more rapidly. 

This can result in runny or loose stool because the reduced transit time decreases the amount of water that is reabsorbed from the waste before it is excreted as feces, and the reduced transit time may increase the frequency of your bowel movements.

Excessive bile production and increased intestinal peristalsis can also lead to feelings of bloating and nausea, as well as gas pains and excessive flatulence on the keto diet.

A jar of artificial sweetners.

#2: Consuming Artificial Sweeteners

Another often overlooked reason for experiencing diarrhea on the keto diet is because of the potential increased intake of artificial sweeteners and sugar alcohols.

Essentially, because the keto diet essentially eliminates all sugar, noncaloric or sugar-free substitutes are frequently used instead.

For example, Splenda or sucralose might be used to sweeten coffee or tea. Many keto-friendly cereals, protein bars, protein powders, snack foods, and flavored yogurts use sugar alcohols such as erythritol and mannitol as a sugar substitute to keep the carbs down.

These types of sugar-free diet foods are often high in artificial sweeteners and sugar alcohols, which are known to cause significant digestive distress. Sugar alcohols, in particular, have been shown to have a laxative effect and cause diarrhea, stomach upset, bloating, gas, nausea, and flatulence.

If you are still experiencing keto diarrhea several weeks or months after switching to the diet, examine whether you are consuming foods that contain sugar alcohols and artificial sweeteners, as the symptoms you are experiencing are likely at least partially attributable to the fact that these compounds are not readily digestible.

A variety of dairy food such as cheese, eggs, butter and milk.

#3: Eating a Lot of Dairy Products

As with following any type of diet, it may also be that certain foods you are eating on the keto diet do not agree with you and are resulting in keto diarrhea.

The most common offender of this type on the keto diet is dairy products.

Many people are lactose intolerant, even if they are not particularly aware of their sensitivity to lactose.

The keto diet encourages the inclusion of full-fat dairy products such as full-fat yogurt, cheese, butter, cream, and whole milk.

Although some full-fat dairy products (such as butter) are naturally low in lactose because the “fat” portion of dairy doesn’t contain lactose, whole milk, full-fat yogurt, and even cheese contain some lactose.

If you have reason to believe that you might be sensitive to dairy or lactose intolerant, consider switching to plant-based, vegan “dairy“ products such as cashew cheese, hemp milk or almond milk, coconut yogurt, and coconut milk. 

Eliminating dairy may help alleviate keto diarrhea.

A person holding their stomach.

#4: The Keto Diet May Disrupt the Gut Microbiome

Although researchers still have yet to learn a lot about the gut microbiome, how it functions, and the various factors that interact with the bacteria residing in your gut, what is known is that it plays an essential role in digestion, immunity, nutritional absorption, reducing the risk of diseases, decreasing inflammation, and producing vitamin K and certain B vitamins.

A healthy gut microbiome has a specific balance of different beneficial bacterial species, and the diversity, as well as the relative populations of each of these types of bacteria, play a significant role in the function of the microbiome as a whole, as well as your digestive and immune health.

More research is still necessary for this area, but some studies suggest that high-fat diets, such as the keto diet, can cause adverse changes to the gut, including inflammation, dysbiosis, or changes in the populations of healthy vs pathogenic gut bacteria, and a decrease in the production of beneficial fatty acids.

If the composition of the gut microbiome changes and the gut lining becomes inflamed because of the high-fat keto diet, you may have difficulty digesting and absorbing your nutrients, leading to diarrhea on keto or other high-fat diets.

The word probiotic and fermented foods.

How to Prevent Keto Diarrhea

There are several things you can do to potentially help reduce the risk and severity of diarrhea on the keto diet, including the following:

#1: Cut Back On Dairy

Consider cutting back on the amount of dairy that you are consuming or switching to plant-based dairy alternatives.

#2: Try Probiotics and Prebiotics

The keto diet can cause disruptions to the gut microbiome, so taking a probiotic supplement or a prebiotic and probiotic combined supplement can help support the health and optimal composition of your gut flora.

Studies have found that taking a probiotic supplement on the keto diet may potentially help offset the digestive issues and gut microbiome disruption caused by the keto diet.

A notebook showing the keto diet percentages, cheese, eggs, avocado and nutes.

#3: Eat Fermented Foods

Fermented foods, such as sauerkraut, kimchi, kefir, tempeh, and buttermilk, contain natural probiotics, which are the beneficial bacterial strains found in your gut, such as lactobacillus and bifidobacteria.

Eating these foods can be nourishing to the gut microbiome and help populate your digestive tract with the healthy bacteria you need for optimal digestion.

#4: Cut Down On Artificial Sweeteners

It can be hard to eat unsweetened foods when your body is accustomed to the sweet taste but reducing your intake of artificial sweeteners, and sugar alcohols in particular, is not only one of the best ways to reduce keto diarrhea but also optimal for your overall health.

#5: Ease Into the Keto Diet

The body typically doesn’t respond to extreme dietary shifts without digestive consequences. Easing into the keto diet rather than jumping ship immediately from a more balanced macronutrient diet can help your body gradually adjust to the increased fat intake. 

A variety of foods eaten on the keto diet.

This is particularly important or helpful in cases where you’ve been following a low-fat diet. 

If your liver is not accustomed to producing much bile to emulsify and digest the fats found in your food, the high-fat keto diet might cause pretty severe keto diarrhea at first, accompanied by cramping and digestive distress.

If you are experiencing significant or concerning keto diarrhea that does not seem to resolve or improve after a couple of weeks on the keto diet, you should speak with your healthcare provider or consider another diet. 

Prolonged diarrhea can result in dehydration and nutritional deficiencies that may have lasting consequences aside from just impacting the quality of your daily life and how well you feel.

If you are thinking about switching up your diet to improve your tummy troubles, we have a wide variety for you to look at in our diet database.

A plate of vegetables and quinoa.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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