Mediterranean Diet and Metabolic Outcomes in NAFLD/MASLD: A Systematic Review and Meta-Analysis of Randomized...

Non-alcoholic fatty liver disease (NAFLD), recently redefined as metabolic dysfunction associated steatotic liver disease (MASLD), is the most prevalent chronic liver disorder worldwide and is strongly associated with obesity, insulin resistance, and cardiometabolic risk. The Mediterranean diet (MD) has been proposed as a therapeutic strategy for improving metabolic and hepatic outcomes. We hypothesized that adherence to the Mediterranean diet would improve anthropometric, metabolic, and hepatic outcomes compared with control diets in patients with NAFLD/MASLD. A systematic search of PubMed, Embase, Web of Science, and the Cochrane Library was conducted through February 2024. Twenty-three randomized controlled trials (RCTs) were included in the qualitative synthesis, of which 11 trials involving 980 participants contributed to the meta-analysis. Pooled standardized mean differences (SMD) with 95% confidence intervals were calculated using random-effects models. Compared with control diets, the Mediterranean diet was associated with significant reductions in body mass index (SMD -0.43; 95% CI -0.84 to -0.02; p = 0.04) and triglycerides (SMD -0.50; 95% CI -0.88 to -0.12; p = 0.01). No statistically significant differences were observed for body weight, waist circumference, HOMA-IR, fasting insulin, HbA1c, lipid fractions, liver enzymes, or blood pressure. Heterogeneity was moderate to high across several outcomes (I² up to 94%), and most outcomes were graded as low to very low certainty. Overall, the Mediterranean diet produced modest improvements in BMI and triglycerides but did not demonstrate clear superiority over comparator diets for most metabolic or hepatic outcomes. Larger, high-quality randomized trials with standardized dietary definitions and longer follow-up are required to clarify its therapeutic role in NAFLD/MASLD.