New findings explain how it aids weight loss

• Ketogenic diets support short-term weight loss, but the precise mechanisms behind metabolic changes are still unknown.
• New research in mice and humans suggests the ketogenic diet may protect against obesity by increasing specific bile acids and decreasing calorie absorption in the intestines.
• The long-term health effects of the ketogenic diet are not clear, and experts recommend plant-based diets, such as the Mediterranean diet, that promote more favorable gut microbiome diversity.

The ketogenic diet is a low-carbohydrate eating pattern that has been widely tested as a tool for weight loss. Yet exactly how it works to reduce body weight remains unclear.

Some propose that gut bacteria and their byproducts may play a role in the beneficial metabolic effects of a ketogenic diet. However, the specific bacteria or byproducts involved have yet to be well understood.

Now, a new study published in Nature Metabolism suggests that following a ketogenic diet results in changes to the gut microbiome that increase the blood levels of specific bile acids in mice.

These bile acids, namely taurodeoxycholic acid and tauroursodeoxycholic acid, may protect against obesity by decreasing calorie absorption in the intestines. This might lead to a decrease in body weight and fasting blood sugar levels.

Distinguishing their work from typical animal studies, the researchers took additional steps to investigate whether these findings might apply to humans.

They documented similar associations between the bile acids and metabolic traits in two human studies, adding to the potential significance of their findings.

This multimethod research highlights a specific interaction between the host and the gut microbiome that might explain how the ketogenic diet reduces body weight and fasting blood sugar levels in both rodents and humans.