Ketogenic Diet Reduces 67 Percent of Liver Fat
A clinical trial recently published in Cell Metabolism, issued by Cell Press, revealed that a high-fat, low-carbohydrate ketogenic diet yielded greater metabolic benefits than the Mediterranean diet and a low-fat diet in individuals with obesity, according to the science news website Science Daily. The results showed that approximately half of the participants who followed the ketogenic diet no longer met the diagnostic criteria for prediabetes after just four to five months.
Samuel Klein, the study’s principal investigator from the Washington University School of Medicine in St. Louis, Missouri, noted that while weight loss is known to improve metabolic health in people with obesity, the study’s data suggest that reducing carbohydrate intake among those with fatty liver and prediabetes “may produce important therapeutic metabolic effects beyond weight loss alone.”
The study highlighted that approximately 40 percent of adults in the United States suffer from obesity, and physicians often recommend low-fat, low-carbohydrate, or Mediterranean diets for weight loss, without knowing whether any of these patterns offer additional metabolic benefits beyond the effect of weight loss itself. To compare their impacts, researchers enrolled 42 obese individuals with prediabetes and hepatic fat accumulation, randomly assigning them to one of three dietary groups. The research team provided all meals and conducted weekly sessions with a dietitian to ensure adherence to each participant’s assigned plan.
The three diets differed sharply in their proportions of carbohydrates and fats, as follows:
• Ketogenic diet: 4 percent of calories from carbohydrates and 73 percent from fat.
• Mediterranean diet: 50 percent of calories from carbohydrates and 35 percent from fat.
• Low-fat plant-based diet: 70 percent of calories from carbohydrates and only 15 percent from fat.
Researchers adjusted caloric intake for each participant so that all three groups lost approximately 10 percent of their body weight, a goal that took the groups about four to five months to achieve. By the end of the study, participants in all groups showed a significant reduction in body fat, and insulin sensitivity improved across the board, helping their bodies regulate blood sugar more effectively.
Despite similar weight loss rates among the three groups, the ketogenic diet produced the most pronounced changes in liver and metabolic health markers. The key differences can be summarized as follows:
• A 67 percent reduction in liver fat among those following the ketogenic diet, compared to only 45 percent in both the Mediterranean and low-fat plant-based groups.
• The largest increase in glucagon, a hormone that helps reduce liver fat accumulation, was observed in the ketogenic diet group.
• The greatest decrease in blood insulin levels occurred in the same group, another change that contributes to lowering liver fat.
• No increase in blood lipids or cholesterol was recorded in the ketogenic diet group, despite their higher fat intake.
In this context, Max Petersen, the study’s lead author from Washington University in St. Louis, explained that one of the most surprising findings was that those on the ketogenic diet did not experience any rise in blood lipids or cholesterol, even though they consumed the highest amount of fat among the three groups.
After the weight-loss phase, approximately 50 percent of those following the ketogenic diet no longer met the criteria for prediabetes, compared with 29 percent in the Mediterranean diet group and only 7 percent in the low-fat plant-based diet group. Petersen noted that GLP-1-based weight-loss drugs have revolutionized obesity treatment and provided an effective pharmacological option for achieving substantial weight loss, but he emphasized that the study demonstrates that a specific dietary composition can offer additional benefits beyond medication alone.
The study, funded by the U.S. National Institutes of Health and the Barnes-Jewish Hospital Foundation, holds scientific significance as one of the first clinical trials to directly compare the effects of three popular diets on liver fat and insulin sensitivity in individuals simultaneously experiencing obesity and prediabetes.
