Keto And Digestion: A Healthy Relationship?

The ketogenic diet is a popular eating plan that involves cutting carbs and increasing the intake of fats. While it has been shown to have several health benefits, it is important to consider its impact on digestion and gut health. The keto diet can affect digestion in both positive and negative ways. On the one hand, it may lead to constipation or diarrhea due to low fiber intake and electrolyte imbalances. On the other hand, it can reduce inflammation and aid in the treatment of certain digestive disorders such as irritable bowel syndrome (IBS). The keto diet's effect on the gut microbiome is still a subject of ongoing research, with some studies suggesting potential benefits and others indicating possible harm.

Keto may reduce inflammation

Acute inflammation is a natural immune response that protects the body from illness and infection. However, chronic inflammation can contribute to inflammatory disorders, including digestive issues like Crohn's disease and ulcerative colitis.

Some studies suggest that the keto diet could help reduce inflammation in the body. For example, a 6-month study of 59 people found that a low-carb diet decreased several markers of inflammation to a greater extent than a low-fat diet.

Additionally, a study of 13 people with irritable bowel syndrome (IBS) found that a very-low-carb diet improved multiple symptoms, including gas, stomach cramps, and diarrhoea. Another study in New Zealand showed that people who followed a low-carb diet reported a resolution of abdominal bloating and cramping.

Furthermore, a 2019 study found that high-fat diets might cause inflammation of the digestive tract. However, other studies have shown that a keto diet may have positive effects on gut bacteria and reduce intestinal inflammation.

While more research is needed, the keto diet's potential to reduce inflammation could be beneficial for individuals with inflammatory disorders or digestive issues.

It can help with some digestive disorders

The keto diet may help with some digestive disorders, such as irritable bowel syndrome (IBS). IBS is a common and disruptive condition, affecting an estimated 10-20% of people worldwide, with symptoms including abdominal bloating, pain, diarrhoea and/or constipation.

A study by Dr Eric Westman at the University of North Carolina found that a very low-carb diet improved multiple symptoms of IBS in 13 people with the condition. A New Zealand study also found that people on a low-carb diet reported resolution of their abdominal bloating and cramping.

Some people who have tried the keto diet have reported that it helped to alleviate their IBS symptoms. Audra Atkins-Reeves, a 36-year-old IT supervisor from California, said that the keto diet "completely resolved her constipation and reduced her formerly frequent attacks of diarrhoea". Atkins-Reeves had suffered from IBS for decades, and found that the keto diet calmed her gut.

Other studies have also noted that limiting specific types of carbs known as FODMAPs may help treat IBS symptoms. Given that the keto diet naturally limits many foods rich in FODMAPs, it may benefit those with IBS.

However, it is important to note that the keto diet may also cause digestive issues for some people, including constipation and diarrhoea.

It can cause constipation

The keto diet can cause constipation, especially during the transition into ketosis. This is mainly due to a sudden change in the frequency of bowel habits, coupled with difficulty in passing stools (i.e., hard and dry stools).

There are three main causes of keto-related constipation:

Low Fiber Intake

The keto diet often involves cutting out high-fibre foods such as whole grains, high-carb vegetables, legumes, and beans. Fibre is essential for maintaining bowel regularity, and insufficient fibre intake can lead to constipation.

Dehydration

The keto diet can result in a loss of water weight, and if this water loss is not replaced, it can lead to dehydration, which can contribute to constipation.

Electrolyte Imbalance

When following a keto diet, the body expels sodium, magnesium, and potassium instead of retaining them. Electrolytes, especially magnesium, are crucial for pulling water into the intestines, which helps soften stools and facilitate easier passage.

How to Relieve Keto-Related Constipation

To alleviate constipation caused by the keto diet, it is recommended to:

• Increase vegetable intake, particularly low-carb greens such as broccoli, cauliflower, bok choy, fennel, kale, collards, and cabbage.
• Increase water intake to stay hydrated and replace lost fluids.
• Consume more electrolytes, such as salting food liberally and taking magnesium supplements (200-400 mg daily).
• Consume more fibre-rich foods, such as blackberries, raspberries, and strawberries, which are also low in sugar.

It is important to note that keto-related constipation is typically temporary, and by making these adjustments, most individuals will be able to regulate their digestion. However, if constipation persists or becomes a source of discomfort, it may be advisable to consider adding more carbs and fibre or trying variations of the keto diet, such as cyclical or targeted keto.

It can cause diarrhoea

The keto diet can cause diarrhoea, especially during the first couple of weeks. This happens for a few reasons:

Low digestive enzymes

When you start eating a lot more fat than your body is used to, your liver can take a while to catch up with its bile and digestive enzyme production. This can lead to diarrhoea due to undigested fat.

Low fibre intake

Fibre slows down digestion. Without enough fibre, food can pass through your system too quickly, leading to diarrhoea. The keto diet eliminates high-fibre foods like fruits, starchy vegetables, grains, and legumes.

Medium-chain triglycerides (MCTs)

MCTs are great for energy and boosting ketone levels, but consuming too many can cause urgent diarrhoea.

Artificial sweeteners

On a keto diet, people often consume more artificial sweeteners and sugar alcohols as they look for low-carb alternatives to their favourite foods and drinks. Research has found that excessive consumption of certain artificial sweeteners can have a laxative effect, leading to diarrhoea.

Excessive bile

To break down fat, the liver needs to produce bile, which is a natural laxative. A keto diet requires the liver to release extra bile, and this can push waste through the digestive tract faster than usual, leading to diarrhoea.

It may alter your gut microbiome

The ketogenic diet is a popular eating plan that involves cutting down on carbs and increasing the intake of fats. The keto diet has been shown to benefit cholesterol levels, blood sugar control, weight loss, and brain health. However, it may also have an impact on gut health.

The microorganisms in your digestive tract are collectively known as the gut microbiome. It plays a crucial role in several aspects of health, including digestion, immune function, mental health, and disease prevention.

Some research suggests that the keto diet could negatively impact the concentration and composition of gut bacteria. For example, a six-month study in 217 people linked a high-fat diet to unfavourable gut changes, including increased inflammation and reduced beneficial fatty acids. Another study in 23 children with epilepsy showed that three months of the keto diet damaged their gut microbiome composition compared to a control group.

However, other studies have found inconsistent results. For instance, a small study revealed that one week of the keto diet reduced seizure frequency in infants by 50%. It also reduced concentrations of proteobacteria, a form of harmful gut bacteria.

Due to these conflicting findings, more research is needed to understand how the keto diet affects the gut microbiome. While it may have some negative impacts, it's important to note that the keto diet can also be beneficial for gut health in some ways. For example, it has been shown to reduce inflammation and help treat conditions like IBS and Crohn's disease.

Frequently asked questions