A randomized clinical trial published in Cell Metabolism found that a ketogenic (keto) diet reduced liver fat by 67% in adults with obesity, prediabetes, and excess liver fat, outperforming Mediterranean and low-fat diets in key metabolic measures.
The study tracked 42 participants over a short-term period, assigning them to one of three weight-loss diets: a low-carb keto diet (4% carbs, 73% fat), a Mediterranean diet (50% carbs, 35% fat), or a low-fat, plant-based diet (70% carbs, 15% fat). All groups experienced improvements in muscle insulin sensitivity, but the keto diet showed superior outcomes in liver-related metrics.
Key findings included:
- Liver fat reduction: Participants on the keto diet saw a 67% decrease in liver fat, compared to 45% in the other groups.
- Liver insulin sensitivity: Improved two to three times more in the keto group than in the Mediterranean or low-fat groups.
- Prediabetes reversal: 50% of keto dieters no longer met prediabetes criteria by the trial’s end, versus 29% on the Mediterranean diet and 7% on the low-fat diet.
- Glucose and insulin measures: Showed greater improvement in the keto group.
Researchers noted that the short duration (likely weeks) and small sample size (14 per group) limit the generalizability of the findings. They concluded that diet composition may influence metabolic outcomes beyond weight loss alone for individuals with obesity, prediabetes, and excess liver fat.
Study limitations and expert response
The trial’s short timeframe and limited participant pool were cited as constraints by the researchers. Experts not involved in the study emphasized the need for longer-term research to confirm whether these metabolic benefits persist or translate to reduced disease risk over time.
Diet comparisons and metabolic effects
The keto diet’s high fat, very low-carb approach stood out for its impact on liver fat and insulin sensitivity. The Mediterranean diet, often recommended for metabolic health, showed moderate improvements but lagged behind keto in liver-specific outcomes. The low-fat diet had the least pronounced effects on liver fat and prediabetes reversal.
Broader implications for metabolic health
The study suggests that dietary macronutrient composition—not just calorie reduction—may play a critical role in managing liver fat and insulin resistance. However, researchers cautioned that individual responses to diets can vary widely, and broader population studies are needed to validate these findings.
Context: Liver fat and metabolic disease
Excess liver fat is a known risk factor for type 2 diabetes, fatty liver disease, and cardiovascular conditions. Prediabetes, characterized by elevated blood sugar levels, often precedes full-onset diabetes. Lifestyle interventions, including diet, are primary strategies for reversing these conditions.