Keto diet reduced liver fat by 67% in obesity trial

A clinical trial published in Cell Metabolism suggests that a very low-carbohydrate, high-fat diet can offer greater metabolic benefits to people with obesity than two other widely recommended eating plans, even when weight loss is equivalent. The study was led by researchers at Washington University School of Medicine in St. Louis.

Comparing three diets

The trial enrolled 42 participants with obesity, prediabetes, and fatty liver disease. They were randomly assigned to a ketogenic diet, a Mediterranean diet, or a low-fat, plant-forward diet. Researchers supplied all food, and participants met weekly with a dietitian to stay on track.

The ketogenic diet derived just 4% of calories from carbohydrates and 73% from fat. The Mediterranean diet provided 50% of calories from carbohydrates and 35% from fat, while the plant-forward diet supplied 70% from carbohydrates and 15% from fat. Calorie intake was adjusted individually so all groups would lose about 10% of body weight, a process that took roughly four to five months.

Largest liver fat reduction with keto

Although weight loss and improvements in insulin sensitivity were similar across all three groups, the ketogenic diet produced the most pronounced metabolic changes. Liver fat dropped by an average of 67% in the keto group, compared with 45% in both the Mediterranean and plant-forward groups. Keto participants also showed the largest increase in glucagon, a hormone linked to reduced liver fat storage, and the steepest decline in blood insulin levels.

Researchers noted it was surprising that keto participants did not see a rise in blood fat or cholesterol despite consuming the highest amount of fat.

Prediabetes improved most with keto

After the intervention, about 50% of ketogenic diet participants no longer met the criteria for prediabetes, compared with 29% in the Mediterranean group and just 7% in the plant-forward group. The researchers concluded that specific diet composition can provide additional benefits beyond weight loss alone. The study was funded by the National Institutes of Health and the Foundation for Barnes-Jewish Hospital.