A small but tightly controlled clinical trial found that a ketogenic diet produced greater improvements in liver health and metabolic function than either the Mediterranean diet or a low-fat, plant-forward diet, even when all three groups lost roughly the same amount of weight.
The study involved 42 participants who had obesity, prediabetes, and fatty liver disease. Researchers randomly assigned each person to one of the three diets and provided all food directly, removing the guesswork that often weakens nutrition studies. Participants also met with a dietitian weekly. Calorie intake was adjusted for each individual so that everyone lost about 10% of their body weight over four to five months.
The macronutrient breakdown differed sharply between groups. The keto diet provided 4% of calories from carbohydrates and 73% from fat. The Mediterranean diet provided 50% of calories from carbohydrates and 35% from fat. The plant-forward diet provided 70% of calories from carbohydrates and 15% from fat.
By the end of the study, all three diets produced significant reductions in body fat and improved insulin sensitivity. But the keto group showed the largest gains across multiple markers of liver and metabolic health. Liver fat dropped by an average of 67% in the keto group, compared with 45% in the other groups combined.
The keto group also showed the greatest reduction in blood insulin levels and the largest increase in glucagon, a hormone that promotes fat loss in the liver.
One result stood out as unexpected. "The most surprising finding was that participants in the ketogenic diet group didn't experience an increase in blood fat or cholesterol levels despite consuming the most fat," said Max Petersen, MD, assistant professor in medicine and the study's first author at Washington University School of Medicine, in a press release.
The diabetes reversal numbers were also striking. By the end of the study, roughly half of the keto group no longer met the criteria for prediabetes. That compared with 29% in the Mediterranean diet group and just 7% in the plant-forward group.
The findings, reported by Healthline, suggest the keto diet may be a particularly effective option for people dealing with the overlapping conditions of obesity, prediabetes, and fatty liver disease. Researchers noted the study was small, and larger trials would be needed to confirm the results across broader populations.
