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Do you get diarrhea on keto: Keto diet diarrhea: Causes and treatments

Keto diet diarrhea: Causes and treatments

Some people who follow a keto diet may experience diarrhea and other gastrointestinal (GI) problems as side effects.

In some cases, diarrhea or GI issues may be short term while the person’s body adjusts to the new diet. However, these problems can sometimes be more long term and even last the duration of the keto diet.

In this article, we explain what a keto diet is, why it can cause GI problems, other possible symptoms, how to relieve symptoms, and when to see a doctor.

Share on PinterestConsuming a greater amount of dairy when beginning a keto diet may lead to diarrhea and other GI problems.

A ketogenic diet, or keto diet, is a diet that is high in fat, moderate in protein, and very low in carbohydrate.

Typically, the body uses carbohydrates as an energy source. When there are insufficient carbohydrates in the body, it enters a state called ketosis. During ketosis, the body breaks down stored fat to create molecules called ketones, which it uses as fuel instead of carbohydrates.

Research examining the keto diet has found that it can successfully help people lose weight by improving fat oxidation. Fat oxidation is a process in which the body breaks down fatty acids.

Additional evidence from human studies suggests that the keto diet may have beneficial effects on blood sugar levels and insulin resistance, among other markers of health. However, more long-term research is necessary to understand exactly how the keto diet affects overall health.

Despite the evidence to support the benefits of a keto diet, other research suggests that eating this way can have some adverse effects. These may include:

  • diarrhea
  • constipation
  • vomiting
  • abdominal pain

As with any extreme dietary changes, starting on the keto diet can have an effect on a person’s stomach and intestines, causing GI problems.

Some people may continue to have GI problems throughout the keto diet. A person on a keto diet must consume a lot of fat and little carbohydrate to reach and maintain ketosis. Some people may find that their body struggles to adjust to the high fat content of this diet.

There are a few other reasons why people on a keto diet may experience GI problems. These include:


Gut microbiota refers to microorganisms in the GI tract. These mainly consist of bacteria that are important to health in many ways, including helping the body absorb nutrients.

A 2019 study found that diets high in fat might cause inflammation of the digestive tract, a decrease in healthful fatty acids, and unfavorable changes in the gut microbiome.

However, other studies have shown that a keto diet may have positive effects on gut bacteria. More high quality research is necessary to determine the effects of the keto diet on gut health.

High fat

To break down fat, the liver needs to produce bile. A diet high in fat requires the liver to release extra bile. As bile is a natural laxative, an excessive amount may push waste through the digestive tract quicker than usual, leading to diarrhea.

The high fat and low carb content of the keto diet may also lead to other gastrointestinal symptoms, such as nausea and bloating.

Artificial sweeteners

During a keto diet, people may consume more artificial sweeteners and sugar alcohols than usual if they try to find low carb alternatives to items that they previously consumed. For example, they may wish to replace the sugar in tea and coffee.

Research has found that excessive consumption of certain artificial sweeteners can cause a laxative effect, leading to diarrhea.

Diarrhea may not be the only symptom that manifests when a person begins a keto diet. People may also experience the following symptoms:

  • constipation
  • cramping
  • abdominal bloating
  • nausea
  • abdominal pain
  • vomiting

If someone on the keto diet is experiencing GI problems, they can try to relieve the symptoms by:

  • Eating more fiber: Fiber can help relieve constipation or diarrhea. Greens, cucumber, broccoli, and cabbage are some high fiber foods that are suitable as part of a keto diet.
  • Eating less dairy: As whole dairy products are high in fat, people starting on a keto diet may consume more of these than they previously did. This dietary change may reveal an intolerance to dairy, common symptoms of which are diarrhea, bloating, and gas.
  • Easing into the diet: A sudden change in the diet may disrupt the GI bacteria. Easing into a keto diet by slowly reducing carbs and increasing fats may help the body adapt better.
  • Staying hydrated: Drinking can help improve constipation. If a person is experiencing diarrhea, it is important to replace fluids. Drinking water and sugar-free electrolyte beverages can help replace these fluids and any lost electrolytes.
  • Adding probiotics and prebiotics: Taking a probiotic supplement or increasing the intake of probiotic- and prebiotic-rich foods may effectively support the gut bacteria during a keto diet. Doing this may reduce the GI effects of a keto diet.
  • Eating fermented foods: Eating fermented foods, such as sauerkraut and kimchi, can help improve digestion, possibly reducing constipation or diarrhea.
  • Decreasing the intake of sugar substitutes: Cutting back on the intake of foods and beverages that contain keto-friendly sugar substitutes may help relieve gastrointestinal symptoms.

Before making any significant lifestyle or dietary changes, it is always worth consulting with a healthcare professional.

Anyone who is experiencing diarrhea that is severe or lasts longer than a week should consult their doctor.

Similarly, if constipation is long lasting or extremely painful, it is best to seek medical attention.

For most people, following an extreme diet such as the keto diet is not necessary for weight loss or to improve health.

People interested in trying a low carb diet may wish to consider working with a qualified dietitian to see what dietary changes would work best for their lifestyle. Less restrictive dietary patterns can often produce similar benefits without the risk of uncomfortable side effects.

A keto diet is a diet that largely consists of foods that are high in fat and low in carbs. During a keto diet, the body goes into a state of ketosis in which it uses fat instead of carbohydrates for energy.

Research has shown that a keto diet may aid weight loss. However, as the diet can lead to changes in the digestive tract, it can also cause adverse GI effects, such as diarrhea and constipation.

To relieve diarrhea and constipation that is due to the keto diet, people should consider taking steps such as eating more fiber, taking probiotic supplements, and easing into the diet.

If the symptoms of GI upset are severe, long lasting, or painful, it is best to seek medical attention.

What do I do if I get diarrhea on a ketogenic diet?

There are three common errors made with a poorly-formulated low carbohydrate diet that can cause stomach and intestinal upset and diarrhea: sugar alcohols, too much protein, and the wrong source of dietary fats.

A well-formulated ketogenic diet is a key component for effective diabetes reversal. When done right, diarrhea is not a common side effect of this nutritional plan. If it occurs, it is likely due to well-intentioned but incorrect food choices. But while sorting this out, it is important that you stay hydrated and replenish your electrolytes!

It is also important to note that there are many causes of diarrhea independent of a ketogenic diet, so contact your doctor if your diarrhea causes severe symptoms or lasts longer than a week.

You may need to take a closer look at what you are eating.

Ask yourself a few questions:

1. Are you a frequent consumer of sugar free beverages, candies, protein/diet bars, and sugar substitutes? These can cause diarrhea.

Sugar free and low carb products frequently contain sugar alcohols to give them a sweet taste while avoiding table sugar (sucrose). These sugar alcohols (xylitol, sorbitol, mannitol, maltitol, lactitol, and isomalt) have been known to cause gastrointestinal distress (Makinen, 2016). Of these, sorbitol is the least tolerated, but all of them can cause gas, nausea, and diarrhea if consumed above one’s level of tolerance. Thus, eating fewer products containing sugar alcohols may help with your diarrhea.

This video explains the connection between sugar alcohols and gastrointestinal distress:

2. Are you eating low carb, low fat, and high protein? Too much protein can lead to diarrhea.

Remember, a well-formulated ketogenic diet is low carb, high fat, and moderate protein. When cutting carbs, it can be tempting to increase your protein without increasing your fat, but the resulting high protein diet can lead to diarrhea (Speth, 1983). It is important to keep protein at about 10-20% of your daily energy need and add ‘good fat’ for satiety. More on what constitutes ‘good fats’ below. Read more on how much protein you need on a ketogenic diet

3. Are you choosing the right sources of dietary fat? Some oils can cause diarrhea.

While a little bit of omega-6 and omega-3 essential fats are required from our diet, more is not better. In particular, our digestive systems have a limited tolerance for vegetable and seed oils high in omega-6 fats. Early in our human research, we found out that feeding our patients a high fat diet made with soybean, corn, safflower, or sunflower oils promptly made them feel nauseated and caused diarrhea. Given that a well-formulated ketogenic diet eaten to maintain body weight provides 70-80% of one’s daily energy intake as fat, the majority of this fat intake needs to come from mono-unsaturated and saturated sources such as olive oil, high oleic versions of safflower and sunflower, coconut oil, lard, butter, cream, and high fat cheese.

Here are some fats and oils that we recommend:

How the keto diet can cause diarrhea

A high-fat diet can tie you to the toilet.


Eat as much fat as you want, they said, you’ll lose weight quickly, they said… Yes, much faster! On social networks, the keto diet looks funny: scroll the #keto tag on Tiktok, and you will see a lot of keto recipes – bell pepper sandwiches instead of bread, cucumber dipped in stevia (to look like watermelon, but without sugar), keto popcorn from cubes of cheese + a lot of joyful advertising from keto fans who brag about their successes without denying themselves anything fat.

It’s great, of course, when a diet brings joy and pleasure! But when certain keto side effects begin to show, that pleasure often fades away. You’ve probably heard about the keto flu and low-carb shortness of breath by now, but here’s another surprise that not every keto seller honestly warns about: keto diarrhea. “The situation is so serious that I just can’t leave the house, and there are constant stomach cramps,” one Reddit user admitted in the “Keto diarrhea” topic.

“Had to rush to the bathroom in the middle of the night,” writes another panelist, a keto newbie, “Now it’s all day long and it sucks to say the least.” Of course, keto fans in the comments unanimously advise not to give up, they say, everything is fine, keto brothers, this happens to some when switching to a keto diet. But how normal is this really? What about keto upsets the stomach so much? How long will it last? When do you need to see a doctor? Here are the experts’ answers.


What is keto diarrhea?

Although diarrhea is a common side effect of the keto diet, it affects everyone differently. Often, keto diarrhea is steatorrhoea, a specific type of diarrhea caused by excess fat in the stool. It looks a little pale, can be covered with a noticeable greasy film, paints Kari Cassell, a registered dietitian and author of The Domino Diet.

And there is also ordinary diarrhea, characterized by loose, watery stools without excess fat content, Cassell continues to enlighten. Some people experience keto diarrhea within the first few days of starting the diet, while others may come on suddenly weeks or months later, Carey adds another nice touch.

What causes diarrhea on a keto diet?

High fat

The main cause of diarrhea in the keto diet is an excessive proportion of fat in the diet. Fat takes longer to break down in the body than carbohydrates or proteins.

When you start eating tons of fat one day, your digestive system gets a little lost and upset. Part of the fat can fly past – not properly broken down and, accordingly, not fully absorbed by the body – and excreted with feces. This is the same steatorrhoea.

Lack of fiber

Another cause of diarrhea on the keto diet is the loss of fiber that naturally occurs when you cut out high-carbohydrate vegetables and fruits. “Fiber is used to treat constipation, so it can be confusing that low fiber intake is the culprit for diarrhea,” Cassell unravels. “But insoluble fiber actually helps prevent diarrhea.”

Artificial sweeteners

Keto desserts can also cause keto diarrhea. “Many artificial sweeteners are harder to digest,” says Cassell. “If you’re a sweet tooth and binge on keto sugar substitutes, it’s quite possible that they’re causing you an upset stomach with subsequent diarrhea.”

Changes in your gut microbiome

When you’ve been courageously on a keto diet for weeks or months and don’t expect any surprises, sudden diarrhea may be due to adverse changes in your gut microbiome. Without fruits, vegetables, and other plant-based foods, you’re not getting the healthiest prebiotic fiber. And without prebiotic fiber, the most beneficial probiotic bacteria have nothing to eat to multiply or somehow hold on. Thus, keto can directly impair overall gastrointestinal health by reducing beneficial bacteria. This can lead to more diarrhea and other unpleasant side effects.

Are you doomed to permanent keto diarrhea?

A comforting answer is when. If it’s just a matter of getting your digestive system used to breaking down all those fats, then the stools may become firmer within a week or two. But if diarrhea is caused by changes in the microbiome, then it can become permanent, Cassell says.

If diarrhea persists for more than a week, Cassell recommends increasing your fiber intake (by adding low-carb, non-starchy vegetables) and avoiding artificial sweeteners.

When should I see a doctor?

If keto diarrhea (or any diarrhea even without keto) is very severe and lasts more than two days, the Mayo Clinic (USA) experts already recommend that you see a doctor. Frequent, persistent diarrhea can lead to dehydration, which is manifested by dry mouth, dizziness, excessive thirst, lack of urination or dark urine, and general weakness.

And even if keto diarrhea isn’t bad but doesn’t subside after the first few days, it might be time to rethink if this diet is right for you. Do you want to live in fear all the time, trying to constantly be at arm’s length from a white friend?

Diarrhea on the keto diet – causes of diarrhea on keto and how to strengthen the stool

When switching to a keto diet, various responses of the body occur, such as the keto flu, digestive disorders, dizziness, fatigue, but they all do not last long and are completely reversible.

Table of Table of Contents

  • 1 Why diarrhea appears on Keto diet
  • 2 What to do with diarrhea on Keto diet

in all people who suffer from a diet from the usual familiar diet, its symptoms arise together with others symptoms of keto flu: lethargy, drowsiness, apathy, nausea, nasal congestion, subfebrile temperature. But also diarrhea itself can occur independently, and not as a symptom of the keto flu. Diarrhea on a keto diet occurs primarily due to a sharp change in diet, when the body has not yet adapted to digest food that is unusual for it.

Causes of diarrhea on the keto diet

Diarrhea on the keto diet can be caused by the release of excessively consumed fat, in an unchanged form, which is simply not absorbed by the body. This happens with a radical change in diet, when the body simply does not have time to rebuild. The liver receives an enormous load on the production of excess bile for the digestion of dietary fats. If there is stagnation of bile in the gallbladder, this will also be accompanied by pain in the right hypochondrium, nausea and flatulence.

Diarrhea on a keto diet usually occurs in people who are used to eating a lot of carbohydrates. Carbohydrate food contains a large amount of fiber, so a sharp refusal leads to disturbances in the work of intestinal motility and its evacuation function. This is usually temporary and usually goes away after a couple of weeks.

Diarrhea on a keto diet also occurs because when switching to a keto diet, the usual sugar is abruptly abandoned, usually it is replaced by sweeteners that cause loosening of the stool. Sweeteners are divided into:

  • natural sweeteners – tagatose and stevia;
  • artificial sweeteners – sucralose, aspartame, saccharin;
  • sugar alcohols – erythritol, xylitol, maltitol, isomalt.

Many people have a sensitivity to sugar alcohols, since alcohols can cause intestinal disorders. If you use a lot of the same sorbitol, then along with diarrhea, you can earn flatulence and spasms in the intestines. Therefore, sorbitol is also prescribed for cleansing the liver, it has laxative and choleretic properties.

When switching to a keto diet, many beginners start eating too much protein, which can also cause diarrhea on a keto diet.

Also, beginners are initially poorly adapted in fats and consume a lot of unhealthy and unhealthy fatty foods, when preference should be given to monounsaturated and saturated fats – olive and butter, high-fat cheeses, heavy cream instead of animal refractory fats, that is, do not overeat fatty meat and lard.

Another cause of diarrhea on a keto diet can be increased bile production. When too much fat is consumed, the liver begins to produce an increased amount of bile, which can also provoke a violation of the stool. This will be manifested by such symptoms as heaviness in the right hypochondrium, nausea, vomiting, yellow feces. In this case, you should switch to natural fats, for example, eat avocados, fatty nuts and eat meat, limiting oils and heavy cream to reduce the load on the liver.

When switching to a keto diet, there is also a deficiency in electrolyte micronutrients such as sodium, magnesium and potassium. Then you should take mineral supplements, but remember that an excess of magnesium can also lead to loose stools. In such cases, you should limit the intake of micronutrients and consume more bone broth – a natural source of magnesium.

Why else does diarrhea occur on a keto diet. As a rule, there may be a violation in the digestion and absorption of food in the intestines due to inflammation of the intestines themselves, for example, Crohn’s disease.

Another cause of diarrhea on a keto diet can be an intolerance to a particular food. In this case, the feces will not only be liquid, but will also change color, for example, to green or light. You should be more careful about the food you eat, identify and eliminate inappropriate foods from the diet.

What to do with diarrhea on a keto diet

If you have diarrhea on a keto diet, do the following:

  • Drink as much pure or mineral water as possible, at least 2-3 liters per day to replenish the water and mineral balance and avoid dehydration , since with liquid feces the body loses a lot of fluid;
  • Take vitamin and mineral complexes, because diarrhea is especially characterized by the loss of trace elements and electrolytes;
  • Eat soluble and insoluble fiber – bran, nuts, seeds, green vegetables, sauerkraut to fill the intestines and improve its peristalsis.