A ketogenic diet may provide substantial benefits for liver health and prediabetes remission, according to a recent study published in Cell Metabolism. The research, which involved 42 adults diagnosed with obesity, prediabetes, and excess liver fat, compared the effects of a low-carbohydrate ketogenic diet with a Mediterranean diet and a low-fat, plant-based diet.
Participants were randomly assigned to one of the three dietary plans. The ketogenic diet comprised approximately 4% carbohydrates and 73% fat, while the Mediterranean diet consisted of about 50% carbohydrates and 35% fat. The low-fat diet was composed of roughly 70% carbohydrates and 15% fat. Across all three groups, participants experienced an average improvement of 50% in muscle insulin sensitivity, enhancing their body's ability to utilize blood sugar.
Liver Fat Reduction and Insulin Sensitivity
The study found that the ketogenic diet led to a notable decrease in liver fat, with an approximate 67% reduction among participants following this plan. This contrasts with the approximately 45% reduction observed in those adhering to the Mediterranean or low-fat diets. The researchers linked this greater reduction in liver fat to a decrease in the liver's production of new fat.
Furthermore, improvements in liver insulin sensitivity were two to three times greater in the ketogenic group compared to the other diet groups. Glucose and insulin measures also showed more significant improvements in the keto group. By the end of the trial, about 50% of participants on the ketogenic diet no longer met the criteria for prediabetes, compared to 29% on the Mediterranean diet and 7% on the low-fat diet.
Registered dietitian nutritionist Ilana Muhlstein commented on the findings, noting that the study validates the idea that calories are not equal and that macronutrient composition plays a crucial role in metabolic health, even with similar weight loss. She explained that the ketogenic diet group showed a greater reduction in the liver's fat production and metabolic changes consistent with increased fat burning.
Muhlstein suggested that individuals with fatty liver disease might consider transitioning to a lower-carbohydrate diet, as excess calories and metabolic dysfunction can lead to fat accumulation in the liver, even in non-drinkers. She noted that reducing carbohydrate intake can prompt the body to use stored fat for energy.
Study Limitations and Recommendations
The researchers cautioned that the study's short duration and small sample size—approximately 14 individuals per diet group—limit the extent to which these findings can be generalized to the broader population. However, they concluded that for individuals with obesity, prediabetes, and excess liver fat, the composition of a weight-loss diet can significantly influence metabolic outcomes beyond weight loss alone, with the ketogenic diet demonstrating the most significant improvements in liver fat and liver insulin sensitivity in this trial.
The study also noted that participants in the ketogenic group did not experience elevated cholesterol or blood-fat measurements during the trial. Muhlstein advised caution for individuals with a family history of heart disease or those at high risk, suggesting that the ketogenic diet might be a beneficial short-term option for some, particularly those with prediabetes or blood sugar irregularities.
For long-term overall health, Muhlstein recommends transitioning to a diet closer to the Mediterranean pattern after initial weight loss. She noted that the ketogenic diet is not typically recommended for long-term use due to its high saturated fat content and potential for lower fiber intake, which may not be optimal for heart health. She suggested that the ketogenic diet could be a useful short-term strategy for individuals with prediabetes to achieve initial improvements in liver fat and prediabetes remission before adopting a more balanced, long-term eating plan.