Ketogenic Diet Outperforms Mediterranean and Low-Fat Diets in Reducing Liver Fat and Prediabetes
- A ketogenic diet reduces liver fat significantly more than Mediterranean or low-fat diets in patients with obesity, prediabetes, and fatty liver disease, according to a clinical trial published...
- An estimated 40% of adults in the United States live with obesity, and physicians frequently recommend low-fat, low-carbohydrate, or Mediterranean dietary approaches to help patients lose weight.
- The study team provided all meals to the participants and scheduled weekly dietitian consultations to ensure adherence to the assigned regimens.
A ketogenic diet reduces liver fat significantly more than Mediterranean or low-fat diets in patients with obesity, prediabetes, and fatty liver disease, according to a clinical trial published on August 27 in the Cell Press journal Cell Metabolic Process. While participants across all three diet groups lost roughly 10% of their body weight over a period of four to five months, those following the very low-carbohydrate, high-fat ketogenic diet experienced a 67% reduction in liver fat. By comparison, participants assigned to the Mediterranean and low-fat, plant-forward diet groups achieved a 45% average decrease in liver fat.
Comparing Three Popular Weight-Loss Diets in a Controlled Trial
An estimated 40% of adults in the United States live with obesity, and physicians frequently recommend low-fat, low-carbohydrate, or Mediterranean dietary approaches to help patients lose weight. However, researchers have lacked definitive clinical data on whether one dietary strategy delivers metabolic benefits beyond the direct effects of weight loss itself. To examine these differences, corresponding author Samuel Klein and his colleagues at the Washington University School of Medicine in St. Louis, Missouri, enrolled 42 individuals who had obesity, prediabetes, and fatty liver disease.
The study team provided all meals to the participants and scheduled weekly dietitian consultations to ensure adherence to the assigned regimens. The diets varied substantially in macronutrient composition. The ketogenic diet provided just 4% of total calories from carbohydrates and 73% from fat, incorporating foods rich in saturated fat including animal products. The Mediterranean diet derived 50% of calories from carbohydrates and 35% from fat, emphasizing plant-based foods like vegetables, olive oil, and nuts alongside moderate amounts of fish and dairy. The plant-forward, low-fat diet supplied 70% of calories from carbohydrates and 15% from fat. Investigators adjusted caloric intake for every participant so that individuals in all three groups would achieve the same target of losing approximately 10% of their initial body weight over four to five months.
Metabolic Outcomes Beyond Weight Loss
By the conclusion of the trial, participants in every diet group had significantly reduced their total body fat and improved their insulin sensitivity, which helps the body regulate blood glucose more effectively. Despite the identical magnitude of weight loss across the cohorts, the ketogenic diet produced the most pronounced changes in liver health and metabolic markers. Liver fat fell by an average of 67% among participants following the ketogenic plan, compared to the 45% reduction observed in both the Mediterranean and plant-forward groups.
Furthermore, roughly half of the participants in the ketogenic group no longer met the clinical criteria for prediabetes after four to five months on the diet. Researchers tracked participants’ metabolism continuously over 24-hour periods by monitoring blood chemistry. Individuals assigned to the ketogenic diet exhibited the largest increase in glucagon, a hormone that assists in reducing stored fat within the liver, alongside the greatest decrease in circulating blood insulin levels, which also contributes to lowering hepatic fat accumulation.
We understand weight reduction can enhance metabolic health in individuals who are overweight. Our data recommend that if you have high liver fat material and prediabetes, lowering carbohydrate consumption can have essential healing impacts on metabolic process beyond simply weight reduction alone.
Samuel Klein, Washington University School of Medicine in St. Louis