Mouse Study Uncovers Hidden Risks of Ketogenic Diets

Long-term high-fat, low-carb regimens may trigger fatty liver, abnormal blood fats, and poor glucose control despite weight loss.

Feb. 1, 2026 at 10:55am

Got story updates? Submit your updates here. ›

Researchers at the University of Utah Health conducted a study on mice fed different diets, including a strict ketogenic diet, for around nine months or more. The study found that while the mice on the ketogenic diet gained less weight, they also developed fatty liver disease, unhealthy levels of fats in the blood, and impaired blood sugar regulation. The findings suggest potential long-term safety concerns with prolonged ketogenic diets, which have become popular for weight loss and diabetes management.

Why it matters

The study begins to address gaps in long-term safety data for ketogenic diets, which have been widely adopted despite limited evidence on the effects of strictly following such a high-fat, low-carb regimen for extended periods. The findings raise questions about the potential health trade-offs of ketogenic diets beyond just weight loss.

The details

In the study, mice were separated into four diet groups: a traditional ketogenic diet, a high-fat Western diet, a protein-matched low-fat diet, and a low-fat, high-carb diet. While the ketogenic diet mice gained less weight, they developed fatty liver disease, unhealthy blood fat levels, and impaired blood sugar regulation. The researchers found that when the ketogenic diet mice were given carbohydrates again, their blood sugar spiked and stayed high, indicating their bodies were not releasing enough insulin.

  • The study ran for around nine months or more.

The players

University of Utah Health

The institution where the researchers who conducted the mouse study are based.

Amandine Chaix

An assistant professor of nutrition and integrative physiology at the University of Utah Health and the senior author of the study.

Molly Gallop

The lead author of the study and a physiologist.

Got photos? Submit your photos here. ›

What they’re saying

“The problem is that when you then give these mice a little bit of carbs, their carb response is completely skewed...Their blood glucose goes really high for really long, and that's quite dangerous.”

— Amandine Chaix, Assistant Professor

“I would urge anyone to talk to a health care provider if they're thinking about going on a ketogenic diet.”

— Molly Gallop, Physiologist

What’s next

The researchers say more long-term studies are needed to fully understand the potential health impacts of prolonged ketogenic diets in humans.

The takeaway

This mouse study suggests that while ketogenic diets may lead to weight loss, they could also trigger concerning metabolic changes like fatty liver disease and blood sugar dysregulation if followed strictly for extended periods. The findings highlight the need for more research on the long-term safety of these diets.