Keto Diarrhea: One Shot Keto's Unwanted Side Effect?

The ketogenic diet is a popular, high-fat, low-carbohydrate diet that has been linked to several health benefits, including weight loss, improved blood sugar control, and therapeutic effects for people with epilepsy and type 2 diabetes. However, one of the most common side effects of this diet is keto diarrhea, characterised by loose, watery stools. This occurs due to several factors, including an increase in fat intake, a decrease in fibre intake, changes in gut bacteria, and the consumption of artificial sweeteners and sugar alcohols, which are common in keto products. While keto diarrhea usually occurs during the initial phase of the diet, it can also happen weeks or months later as the body adjusts to the high-fat content.

High fat content

The keto diet is a low-carb, high-fat diet. This high-fat content can cause diarrhea, as the body may struggle to adjust to the high-fat content of the diet.

Fat takes longer to break down in the body than carbohydrates or protein. When you suddenly start eating a lot of fat, your digestive system can struggle to keep up. Some of the fat may be malabsorbed, not broken down properly, and excreted in your stool. This can lead to steatorrhea, a specific type of diarrhea caused by too much fat in the stool.

The keto diet can also cause bile acid malabsorption. Bile is a natural laxative, and a diet high in fat requires the liver to release extra bile. This can push waste through the digestive tract faster than usual, leading to diarrhea.

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

The high-fat content of the keto diet can be a shock to the body, and it may take some time for the body to adjust to this new way of eating. During this adjustment period, it is common to experience some temporary side effects, such as diarrhea.

Lack of fibre

The keto diet is a very high-fat, very low-carb, and moderate protein eating plan. The diet induces a phenomenon called ketosis, where the body burns fat instead of glucose for energy.

The keto diet can cause diarrhea, known as "keto diarrhea," due to several factors, including an increase in fat intake, a decrease in fiber intake, and changes in gut bacteria. The sudden lack of fiber from cutting carbohydrates can lead to diarrhea as insoluble fiber bulks stools and helps prevent diarrhea.

How to Increase Fiber Intake on the Keto Diet

• Avocados — Half an avocado contains 1.4 net carbs and 5 grams of fiber.
• Chia Seeds — One ounce of chia seeds offers 9.6 grams of fiber and 2.2 grams of net carbs.
• Nuts — Pecans and almonds are low-carb nuts that provide fiber.
• Flax Seeds — One tablespoon of ground flax contains 2 grams of fiber and 0 net carbs.
• Non-Starchy Vegetables — Collards, broccoli, asparagus, and cauliflower are keto-friendly and high in fiber.
• Berries — Raspberries, in small amounts, can be a good source of fiber on the keto diet.
• Citrus Fruits — Citrus fruits, such as oranges and lemons, can provide soluble fiber.

When to See a Doctor

If keto diarrhea persists or becomes severe, it is recommended to consult a doctor, especially if it lasts for more than two to three days. Additionally, if you experience symptoms of dehydration, such as dark-colored urine, dry skin, dizziness, or excessive thirst, seek medical attention.

Artificial sweeteners

While artificial sweeteners can be a helpful way to satisfy sweet cravings while on the keto diet, they may also have some negative side effects. For example, excessive consumption of certain artificial sweeteners can cause a laxative effect, leading to diarrhea. Additionally, some people may experience bloating, gas, and digestive issues when consuming artificial sweeteners. It is important to note that the impact of artificial sweeteners can vary from person to person.

To maintain ketosis and avoid potential side effects, it is recommended to choose artificial sweeteners wisely and consume them in moderation. Some artificial sweeteners may impact blood sugar and insulin levels, so it is advisable to monitor your intake and consult a healthcare professional if you have any concerns.

Gut microbiome changes

The keto diet can cause changes to the gut microbiome, which can lead to keto diarrhea. The diet's high fat and low carb content can cause an increase in "good" bacteria in the gut, but it can also lead to a decrease in healthy bacteria, as the diet eliminates many prebiotic-rich foods.

A 2019 study found that high-fat diets might cause inflammation of the digestive tract, a decrease in healthy fatty acids, and unfavourable changes in the gut microbiome. However, it is important to note that more high-quality research is needed to determine the exact effects of the keto diet on gut health.

The standard American diet (SAD) tends to overload the intestinal tract with more fibre and sugar than it is designed to handle, which can result in problems like SIBO and leaky gut. When transitioning to the keto diet, the reduction in fibre and processed sugar starves gut bacteria of their primary fuel source, leading to a "die-off" of these bacteria. This die-off can cause digestive issues, including keto diarrhea, as the body tries to expel the dead bacteria.

The keto diet's high-fat content can also be difficult for the body to adjust to, as it requires an increase in bile production and digestive enzyme activity. The body's bile supplies can be stretched thin, and bile problems are common in individuals with pre-existing digestive issues.

Additionally, the keto diet can lead to nutrient deficiencies, particularly of fat-soluble vitamins like Vitamin A and Vitamin D, which are important for maintaining gut health and regulating bile acid production.

To summarise, the keto diet's impact on the gut microbiome is twofold: it can lead to an increase in "good" bacteria, but also to a decrease in healthy bacteria due to the elimination of prebiotic-rich foods. This, combined with the high-fat content of the diet and potential nutrient deficiencies, can contribute to digestive issues, including keto diarrhea.

Bile acid malabsorption

BAM is not a standalone condition and is often associated with other health issues such as Crohn's disease, chronic or recurrent diarrhea, and large intestine inflammation (microscopic colitis). It is caused by the body producing too much bile or not being able to use it correctly. Bile is a liquid substance produced by the liver to aid in food digestion. While the body typically releases bile at the correct levels based on the food consumed, sometimes there can be an overproduction or improper utilization, leading to BAM.

There are two main tests available for diagnosing BAM: the fecal bile acid test and the serum 7αC4 test. Treatment options include medication (primarily Cholestyramine), surgery to remove the gallbladder, and diet changes to reduce fat intake.

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