What To Do If You Have Diarrhea On A Keto Diet

  • Post last modified:August 11, 2021
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Almost everyone who follows a keto diet may experience some side effects. This is because when you change your eating habits, your body needs time to adapt. 

During this process, you may experience some uncomfortable feelings. Frequent diarrhea is one of the common symptoms. 

In this article, we will discuss what to do if you have diarrhea on a keto diet.

What Is A Ketogenic Diet?

The keto diet is a very low carbohydrate diet. Due to its obvious weight loss effect, the keto diet has become more and more popular in recent years.

The nutritional ratio of the ketogenic diet is:

  • 5% carbohydrates, 20% protein, and 75% fat.

When you follow a keto diet, your body enters a metabolic state called ketosis. In this state of ketosis, your body decomposes and burns stored fat instead of glucose as an energy source 

Studies have found that the keto diet can successfully aid weight loss by improving fat oxidation. Fat oxidation is the process by which the body breaks down fatty acids. At the same time, the keto diet also has a positive effect on blood sugar and insulin levels.

However, when changing from a high-carb diet to a low-carb diet, many people may experience some adverse reactions, such as:

  • headache
  • insomnia
  • constipation
  • diarrhea
  • bloating
  • hair loss
  • bad breath

… …

These symptoms will usually disappear when your body is fully adapted to the new diet. Generally speaking, this process takes several days to several weeks, depending on an individual’s physical condition.

In addition, if your body drops out of ketosis during this adaptation process, it can also prolong the time of these adverse reactions.

What To Do If You Have Diarrhea On A Keto Diet

What Causes Diarrhea On A Keto Diet?

Any extreme changes in diet can affect the gastrointestinal tract.

In order to stay in ketosis, the ketogenic diet requires the strict restriction of carbohydrates intake, while eating a lot of fat.

However, some people find it difficult for their bodies to adapt to such a high-fat content diet. As a result, they are likely to have diarrhea.

The reasons for this reaction include:

1. Intestinal flora imbalance

The group of microbes in the gut plays an important role. Many of these are beneficial bacteria that can help your body absorb nutrients.

When you significantly change your diet, such as drastically reducing carbohydrates, the intestinal flora may lose its balance.

In the traditional high-carb diet, gastrointestinal microbes feed on short-chain fatty acids in grains, fruits and vegetables. However, the keto diet restricts these short-chain fatty acids [*].

Therefore, as long as you continue your ketogenic diet, the intestinal flora will gradually adapt it and make corresponding adjustments to return to its original balance. The downside is that during this process you may still experience some discomfort which is called “keto flu“.

2. Inability to absorb fat

Your body works hard to break down fat. Some people are not used to metabolizing the fat contained on a keto diet.

When you consume too much fat and your body cannot keep up with the rate of decomposition and absorption, the excessive fat will absorb more water, after entering the small intestine and colon to help it pass. As a result, you may experience watery diarrhea.

There are a small number of people who continue to suffer from diarrhea while following the ketogenic diet because their bodies cannot absorb and use all the fat.

3. Excessive bile secretion

Your liver secretes bile to break down fat. A high-fat diet requires more bile.

Since bile is a natural laxative, too much bile may push waste into the digestive tract faster than usual and cause diarrhea.

This low-carb and high-fat diet may also cause other gastrointestinal symptoms, such as nausea and bloating.

4. Non-nutritive sweeteners

Many people who follow a ketogenic diet avoid nutritive sugars, including those with added sugar and fructose. Instead, they chose artificial sweeteners and sugar alcohols, such as aspartame, sucralose, sorbitol, maltitol or xylitol.

However, studies have found that excessive sweeteners have a laxative effect and can cause diarrhea.

This is because sweeteners are difficult to absorb. They often enter the large intestine without being digested which causes bloating, abdominal pain and diarrhea.

How To Relieve Keto Diarrhea Symptoms

How To Relieve Keto Diarrhea Symptoms

If you have gastrointestinal problems after starting a ketogenic diet, you can try the following methods to relieve symptoms:

  • Drink plenty of water: Diarrhea in the early stage of ketosis can cause your body to shed a lot of water, thereby aggravating the symptoms of ketone flu. Therefore, drinking plenty of water or other liquid (bone soup, Himalayan Pink Salt water) can help replenish body fluids and lost electrolytes.
  • Eat more dietary fiber: Fiber can relieve constipation or diarrhea. Thus, you should eat more low-carb and high-fiber foods, such as green leafy vegetables, broccoli, cabbage, certain seeds and nuts.
  • Eat less dairy products: Many people have lactose intolerance and some dairy products can cause gastrointestinal discomfort. If you can, reduce these types of foods to see if the diarrhea problem is resolved.
  • Eat more fermented foods: Fermented foods such as sauerkraut, pickles and kimchi can help improve digestion. In addition, eating these foods may reduce gastrointestinal symptoms such as constipation or diarrhea.
  • Supplement probiotics and prebiotics: You can take probiotic supplements or eat more foods rich in prebiotics, such as apples, walnuts, onions, etc. These foods can promote the balance of intestinal flora and help reduce the impact of the keto diet on the gastrointestinal tract.
  • Eat less non-nutritive sweeteners: Try to reduce the intake of food and beverages containing artificial sweeteners or sugar alcohols, which can help you relieve diarrhea symptoms.
  • Increase fat intake gradually: Sudden changes in any diet can lead to an imbalance of the intestinal flora and cause digestive problems such as diarrhea. You can try to slowly reduce carbohydrates and gradually increase fat. In this way, you can reduce the burden on your stomach and help your body better adapt to the new diet.

If the diarrhea is severe or lasts more than a week, you should seek medical attention as soon as possible. Another possibility is that this diet may not be suitable for you. If so, you can consider trying other weight loss methods.


The Ketogenic diet requires the strict restriction of carbohydrates while consuming large amounts of fat, so your body can maintain a state of ketosis and burn fat quickly.

However, sudden changes in diet can cause digestive problems such as constipation or diarrhea, which is also one of the adverse reactions of the keto diet.

Some measures can help relieve symptoms, such as eating more fiber, supplementing electrolytes, adding probiotics or reducing fat mass. These methods can help your body better adapt to the new diet.

If you have had severe diarrhea for more than a week, please see a doctor promptly.

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