Long-Term Keto Diet Linked to Serious Metabolic Risks, Study Finds

A recent study from the University of Utah Health has revealed alarming findings regarding the long-term effects of the ketogenic diet, suggesting that while it may prevent weight gain, it could also lead to significant metabolic complications. Published on January 27, 2026, in the journal Science Advances, the research indicates that the diet is associated with serious conditions such as fatty liver disease and impaired blood sugar regulation.

The ketogenic diet, originally developed to treat epilepsy, has surged in popularity as a weight-loss strategy and a means to manage conditions like obesity and type 2 diabetes. The diet is characterized by a very high fat intake and minimal carbohydrates, pushing the body into a state of ketosis where fat is converted into alternative energy sources. Despite its short-term benefits, this study highlights concerning long-term health risks that have not been thoroughly investigated until now.

Study Overview and Methodology

To explore the prolonged impact of the ketogenic diet, Dr. Molly Gallop and her team conducted an extensive experiment involving both male and female mice. The animals were divided into four groups, each assigned a different dietary regimen: a high-fat Western diet, a low-fat high-carbohydrate diet, a traditional ketogenic diet, and a protein-matched low-fat diet. Over a period of nine months, researchers monitored the mice’s body weight, food intake, blood lipid levels, and glucose regulation.

Despite the ketogenic diet preventing weight gain compared to the high-fat Western diet, the study found that any weight gain in the ketogenic group was predominantly due to fat mass rather than lean tissue. This shift raised concerns about the diet’s impact on overall body composition.

Metabolic Complications Identified

One of the most concerning findings was the development of fatty liver disease among the mice on the ketogenic diet. Dr. Amandine Chaix, the study’s senior author, stated, “If you have a really high-fat diet, the lipids have to go somewhere, and they usually end up in the blood and the liver.” While the ketogenic diet effectively controlled weight, it did not protect against fatty liver disease, a critical marker of metabolic dysfunction.

Interestingly, the research revealed significant sex differences in how the diet affected the mice. Male mice experienced severe liver damage and dysfunction, while female mice did not exhibit significant fatty liver accumulation, suggesting a potential biological resilience that warrants further investigation.

The study also uncovered troubling effects on blood sugar control. Initially, the mice on the ketogenic diet showed reduced blood sugar and insulin levels, which might seem beneficial. However, when given carbohydrates, their blood glucose levels surged dangerously high and remained elevated for extended periods. This heightened response was attributed to pancreatic cells failing to secrete adequate insulin, likely due to stress from prolonged high-fat exposure.

The reversion of some metabolic abnormalities occurred after discontinuing the ketogenic diet, indicating that certain damages might be reversible.

These findings underscore the importance of understanding the long-term implications of dietary choices. While the ketogenic diet may provide short-term weight loss, individuals contemplating this dietary approach should consider the potential for serious health risks. Dr. Gallop advises, “I would urge anyone to talk to a health care provider if they’re thinking about going on a ketogenic diet.”

This research was made possible through funding from the National Institutes of Health and other notable organizations, emphasizing the study’s credibility and the significance of its findings for public health.