Keto And Oily Stools: What's The Connection?

The ketogenic diet is a low-carbohydrate, high-fat diet that has gained traction in recent years. While it has its benefits, such as improved blood sugar control and weight loss, it also has some unpleasant side effects, including the risk of developing keto flu, strange cravings, bad breath, kidney stones, and gastrointestinal issues.

One of the most common side effects of the keto diet is a change in bowel movements, often referred to as keto poop. This can manifest as either constipation or diarrhoea, and it is typically caused by a sudden increase in fat intake and a decrease in fiber intake. The high-fat content of the keto diet can lead to steatorrhea, a type of diarrhoea caused by excess fat in the stool, which can be foul-smelling and coated in a greasy film.

Additionally, the keto diet can cause a decrease in beneficial gut bacteria and a change in bile acid production, which can further contribute to digestive issues. However, these side effects are usually temporary, and there are strategies to alleviate them, such as increasing water and fibre intake, taking digestive enzymes or electrolyte supplements, and gradually introducing the diet.

Keto can cause constipation

The keto diet is a popular, low-carb, high-fat, and moderate-protein eating plan that is often used for weight loss. However, it can also lead to some unpleasant side effects, including constipation.

Constipation is a common issue for people on the keto diet due to the reduced intake of fiber. Fiber is essential for keeping bowel movements regular and consistent. Typically, a person should aim for about 25 grams of fiber per day. However, on the keto diet, many fiber-rich foods like whole grains, fruits, and legumes are restricted, leading to a lower fiber intake.

The lack of fiber in the keto diet can cause constipation, which is characterized by infrequent bowel movements, hard stools, and difficulty passing them. This can result in abdominal discomfort and even hemorrhoids in severe cases.

The risk of constipation is higher for those who previously consumed a lot of fiber from whole grains and fruits, as their bodies are used to a higher fiber intake. Additionally, the high-fat content of the keto diet can also contribute to constipation as fat takes longer for the body to digest.

To combat constipation while on the keto diet, it is recommended to:

• Increase fiber intake by consuming more high-fiber, low-carb foods like avocados, raspberries, non-starchy vegetables (e.g., broccoli, artichokes, collard greens), and nuts.
• Stay hydrated by drinking plenty of water and other fluids.
• Consider taking a fiber supplement, although it's best to prioritize high-fiber foods.
• Include fermented foods like sauerkraut and kimchi, which contain natural probiotics that support gut health.
• Consult a doctor if constipation persists or is severe, as they may recommend a stool softener or laxative.

Diarrhea is also common

While constipation is a common side effect of the keto diet, some people experience the opposite problem. Diarrhea can occur when the body struggles to digest all the fat that a person is consuming on the keto diet. This can lead to an upset stomach and looser, more frequent bowel movements.

According to Ginger Hultin, a spokesperson for the Academy of Nutrition and Dietetics, constipation is often the biggest problem with the keto diet due to the lack of fibre. However, artificial sweeteners and sugar alcohols, as well as a very high-fat diet, can also cause diarrhea.

The keto diet can also impact the composition of the gut microbiome, which has implications for digestion. Hultin notes that some small studies have found that after three months on the ketogenic diet, the bacteria in the gut change, and this could cause diarrhea in some people. If the body is not used to eating more fats, this could alter the gut bacteria, causing diarrhea and looser stools from poor digestion.

Diarrhea may also be a sign of steatorrhea, which is when there is too much fat in the stool. Steatorrhea is a sign of malabsorption, which happens when the body doesn't break down or absorb the foods and nutrients consumed. Over time, this can lead to nutrient deficiency or dehydration.

If you are experiencing keto diarrhea, it is recommended to add more fibre to your diet, drink more water and electrolytes, and consider seeing a doctor if symptoms persist.

Poop may be yellow or foul-smelling

Yellow or foul-smelling poop is a side effect of a low-carb, high-fat, high-protein diet. This is due to excess fat in your stool. While this is not dangerous, it does indicate that your intestines are not absorbing enough nutrients or your liver is not producing enough bile to break down the fat in your diet.

If you notice that your poop has turned yellow or smells foul, it is recommended to consult a doctor if it does not return to a normal colour after a few days.

Causes

Lack of fibre

The keto diet is high in fat and low in carbohydrates, which can lead to a lack of fibre in the diet. Fibre is important for colonic health and helps to add bulk to the stool, making it easier to pass.

High-fat diet

The high-fat content of the keto diet can be hard to digest and can cause a delay in the enzymes that digest fat. This can lead to fat reaching the colon and being digested by bacteria, leading to gas, bloating, and fat in the stool.

Gut microbiome changes

The keto diet can also impact the composition of the gut microbiome, which has implications for digestion. Some studies have found that the bacteria in the gut change after being on the keto diet for a few months, which could cause diarrhoea and looser stools due to poor digestion.

Prevention and Treatment

Increase fibre intake

To combat constipation, it is recommended to eat more high-fibre, low-carb foods such as avocados, raspberries, non-starchy vegetables, and nuts.

Stay hydrated

Drinking plenty of water and staying hydrated is important for preventing and treating constipation and diarrhoea.

Probiotics and fibre supplements

Consuming fermented foods or taking a fibre supplement can also help support gut health and improve digestion.

Reduce artificial sweeteners and sugar alcohols

Artificial sweeteners and sugar alcohols, which are commonly consumed on the keto diet, can cause bloating and diarrhoea when consumed in excess.

When to Worry

If you experience diarrhoea multiple times a day for more than two to three days, or if you are experiencing any symptoms of dehydration, it is recommended to consult a doctor right away.

Additionally, if your poop does not return to a normal colour after a few days, it is advised to seek medical advice.

Gut bacteria is affected

The keto diet can impact the composition of your gut microbiome, which has implications for digestion. Some studies have found that after three months on the ketogenic diet, the bacteria in the gut change quite a bit, and this could cause diarrhoea in some people. If your body is not used to eating more fats, this could alter the gut bacteria, causing diarrhoea and looser stools from poor digestion.

The keto diet can also affect the gut microbiome, the vast network of microorganisms in your digestive tract, which has been linked to immune and metabolic function. Research in animals and some human data shows that high-fat diets lead to fairly rapid and significant changes in the microbiome. However, it is not clear what this means for long-term health.

The gut microbiome may also play a role in disease prevention and progression. For instance, in the context of epilepsy, it may be because of these alterations in the microbiome that keto can potentially help reduce the frequency of seizures.

The bacteria in your gut may also change due to your new diet, and this could be why your appetite decreases.

It can take time to adjust to high-fat foods

It can take time for your body to adjust to high-fat foods. This is because the keto diet is so high in fat and low in carbohydrates, which can be a big change for your body, especially if you're moving from a diet that is low or moderate in fat.

The keto diet is often high in fat (70-80%) and very low in carbohydrates, with many people sticking to 20-50 grams of net carbs (total carbs minus fibre and sugar alcohols) per day. This means that your body may need time to adjust to digesting and absorbing this amount of fat.

The transition period may be challenging, with some people experiencing keto flu, strange cravings, bad breath, kidney stones, constipation, or diarrhoea. These side effects may be due to the body adjusting to a new diet, or they may indicate deeper bodily stress.

For example, constipation may be due to a lack of fibre in the diet, as high-fibre foods like whole grains and fruits are limited on the keto diet. On the other hand, diarrhoea may occur if the body doesn't digest all the fat being consumed, leading to an upset stomach.

It's important to give your body time to adjust to the high-fat content of the keto diet and to seek professional advice if symptoms persist or worsen.

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