The ketogenic diet is a popular eating plan that involves significantly cutting carbs while increasing your intake of heart-healthy fats.

By depriving your body of carbs — your primary energy source — you’re forced to start burning fat instead. The keto diet has been shown to benefit cholesterol levels, blood sugar control, weight loss, and brain health (1).

Still, you might wonder whether this diet can affect other aspects of your health, including digestion and gut health.

This article examines how the keto diet affects gut health.

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Several studies indicate that the keto diet may harm your digestion in the following ways.

May be lower in fiber

The keto diet eliminates high-carb foods like fruits, starchy vegetables, grains, and legumes.

Many of these foods are also high in fiber, an essential nutrient for digestion.

Fiber passes through your digestive tract slowly, helping maintain bowel regularity (2).

Insufficient fiber intake could increase your risk of constipation (3, 4).

High fiber intake is also thought to protect against several digestive disorders, including hemorrhoids, stomach ulcers, gastroesophageal reflux disease (GERD), and diverticulitis (5).

Enjoying a variety of high-fiber, low-carb foods like non-starchy vegetables and low-sugar fruits can help you meet your fiber needs while on a keto diet.

May alter your gut microbiome

The microorganisms in your digestive tract are collectively known as the gut microbiome (6).

It’s thought to play a central role in several aspects of health, including digestion, immune function, mental health, and disease prevention (7, 8).

Some research notes that the keto diet could damage the concentration and composition of your gut bacteria.

One 6-month study in 217 people linked a high-fat diet to several unfavorable gut changes, including increased inflammation and reduced beneficial fatty acids (9).

Another study in 23 children with epilepsy showed that 3 months of the keto diet damaged gut microbiome composition, compared with a control group (10).

However, other studies give inconsistent results.

For example, a small study revealed that 1 week of the keto diet reduced seizure frequency in infants by 50%.

It also reduced concentrations of proteobacteria, a form of harmful, pathogenic gut bacteria that include Escherichia, Salmonella, and Vibrio (11).

Because of these conflicting findings, more research is needed to evaluate how the ketogenic diet affects your gut microbiome.

Summary The keto diet is often low in fiber and may harm the health of your gut microbiome, potentially increasing inflammation and reducing your concentration of good bacteria. That said, research yields mixed results.

Interestingly, some research suggests that the keto diet could benefit digestive health.

May reduce inflammation

Acute inflammation is an immune response that protects your body against illness and infection.

However, chronic inflammation may contribute to inflammatory disorders, including digestive issues like Crohn’s disease and ulcerative colitis (12).

Some studies suggest that the keto diet could help decrease inflammation in your body.

A 6-month study in 59 people found that following a low-carb diet decreased several markers of inflammation to a greater extent than following a low-fat diet (13).

A few animal studies provide similar results (14, 15).

May benefit some digestive disorders

The keto diet may also aid some digestive disorders.

For instance, in a study in 13 people, a very-low-carb diet improved multiple symptoms of irritable bowel syndrome (IBS), a disorder that causes issues like gas, stomach cramps, and diarrhea (16).

Other studies note that limiting specific types of carbs known as FODMAPs may also help treat IBS symptoms (17, 18, 19).

Given that the keto diet naturally limits many foods rich in FODMAPs, it may benefit those with IBS.

What’s more, a 15-month case study of a 14-year-old boy reported that following a combined keto and paleolithic diet relieved symptoms and side effects of Crohn’s disease (20).

Nonetheless, more research is needed on the keto diet and digestive disorders.

Summary Some studies suggest that the keto diet may reduce inflammation and help treat conditions like IBS and Crohn’s disease, although more research is needed.

You can easily enjoy several gut-friendly foods as part of a healthy keto diet. Foods low in carbs but high in gut-boosting benefits include:

  • Avocados. Avocados are not only rich in heart-healthy fats but also fiber, supplying a whopping 10 grams of fiber per cup (150 grams) (21).
  • Leafy greens. Vegetables like arugula, spinach, kale, and cabbage are low in carbs while high in fiber and other beneficial nutrients like antioxidants and vitamins C and K (22).
  • Coconut oil. Some animal studies suggest that coconut oil may reduce inflammation and boost the gut microbiome (23, 24).
  • Kimchi. This staple Korean dish is made from vegetables like cabbage that have undergone fermentation, which boosts their content of beneficial bacteria to support gut health (25).
  • Butter. Butter contains butyric acid, a short-chain fatty acid (SCFA) that may improve digestive health, as well as reduce intestinal inflammation and symptoms of inflammatory bowel disease (26).
Summary Many gut-friendly foods can be enjoyed as part of a healthy keto diet, including fermented vegetables and certain oils.

Studies on the ketogenic diet and gut health provide conflicting results.

On one hand, this eating pattern may reduce inflammation and help treat some digestive disorders.

On the other hand, it may harm your gut microbiome and lead to digestive issues like constipation.

If you decide to follow a ketogenic diet, be sure to eat a variety of gut-friendly foods to promote digestive health.