Keto diet cuts liver fat 67% in trial
A ketogenic diet led to a 67% reduction in liver fat for people with obesity and prediabetes, outperforming Mediterranean and low-fat diets in a clinical
A ketogenic diet provided stronger metabolic benefits than a Mediterranean or low-fat diet for people with obesity, prediabetes, and fatty liver disease, according to a clinical trial published on August 27, 2026, in Cell Metabolism. The study, led by researchers from Washington University School of Medicine, found that while all three diets led to similar weight loss, the keto diet produced a significantly greater reduction in liver fat and prediabetes rates.
Corresponding author Samuel Klein stated that while weight loss improves metabolic health, the data suggest reducing carbohydrate intake can have important therapeutic effects beyond weight loss alone for those with high liver fat and prediabetes. The research was supported by the National Institutes of Health and the Foundation for Barnes-Jewish Hospital.
Comparing the Diets
Doctors often recommend low-fat, low-carbohydrate, or Mediterranean diets for weight loss, but their comparative metabolic benefits were unclear. The trial enrolled 42 people with obesity, prediabetes, and fatty liver disease. Participants were randomly assigned to follow a ketogenic diet, a Mediterranean diet, or a low-fat, plant-forward diet, with all food supplied by the research team.
The macronutrient composition of the assigned diets differed sharply, as detailed in the table below.
| Diet | Carbohydrate Calories | Fat Calories |
|---|---|---|
| Ketogenic | 4% | 73% |
| Mediterranean | 50% | 35% |
| Plant-Forward (Low-Fat) | 70% | 15% |
Key Metabolic Findings
Calorie intake was adjusted so all groups lost about 10% of their body weight over four to five months. Body fat decreased and insulin sensitivity improved across all groups.
Despite matching weight loss, the ketogenic diet drove the most pronounced changes in liver and metabolic health. Liver fat fell by an average of 67% in the keto group, compared with an average 45% reduction in both the Mediterranean and plant-forward groups.
First author Max Petersen noted the most surprising finding was that the ketogenic group did not experience an increase in blood fat or cholesterol levels despite consuming the most fat. Metabolic tracking showed the keto group had the largest rise in the hormone glucagon and the greatest decline in blood insulin levels, changes linked to reducing liver fat.
Impact on Prediabetes
The ketogenic diet also had the strongest effect on prediabetes status. After the intervention, about 50% of participants on the keto diet no longer met the criteria for prediabetes. This compared with 29% of those on the Mediterranean diet and 7% of those on the plant-forward diet.
Max Petersen commented that while GLP-1-based medications have revolutionized obesity therapy, the study shows the specific composition of a diet can provide added benefits. The research indicates that for individuals with specific metabolic conditions, dietary carbohydrate restriction may offer targeted advantages.
