A meta‑analysis of randomized trials comparing ketogenic diets (KD) with Mediterranean diets (MD) in adults found that KD produced greater reductions in body weight, BMI, waist circumference, body‑fat percentage and fasting insulin, while lipid, glycemic and blood‑pressure outcomes were largely similar, except for a modest decrease in total cholesterol with KD.
Study and findings
The authors identified randomized controlled trials that directly compared a ketogenic diet with a Mediterranean diet in adult participants. Using a random‑effects model, they calculated weighted mean differences (WMD) for each outcome. Compared with the Mediterranean diet, the ketogenic diet yielded a mean weight loss of 3.56 kg (95 % CI ‑5.62 to ‑1.49), a BMI reduction of 1.86 kg/m² (‑2.73 to ‑0.98), and a waist‑circumference decrease of 4.25 cm (‑7.46 to ‑1.04). Body‑fat percentage fell by 2.09 % (‑3.98 to ‑0.20) and fasting insulin by 3.15 µU/ml (‑5.02 to ‑1.28). No significant differences emerged for fasting glucose, HbA1c, LDL‑C, HDL‑C, triglycerides, systolic or diastolic blood pressure, or C‑reactive protein. Total cholesterol was lower with the ketogenic diet by 9.71 mg/dl (‑17.79 to ‑1.62). The authors noted evidence of publication bias for triglycerides and LDL‑C.
Clinical interpretation
The data suggest that, within the time frames captured by the included trials, a ketogenic diet can achieve greater short‑term weight loss and modest improvements in body composition than a Mediterranean diet. The lack of consistent advantage for glycemic indices, most lipid fractions, blood pressure and inflammatory markers indicates that the two dietary patterns are broadly comparable for cardiometabolic risk factors, aside from a small reduction in total cholesterol with the ketogenic approach. Clinicians should therefore weigh the magnitude of weight loss against considerations of dietary adherence, long‑term sustainability and individual patient preferences when selecting between these patterns.
Limitations and open questions
The analysis is limited to published randomized trials; heterogeneity in diet composition, caloric prescription and intervention duration may influence the pooled estimates. Publication bias detected for triglycerides and LDL‑C raises uncertainty about the true effect on these lipids. Most trials reported outcomes over relatively short periods, so the durability of weight loss and metabolic effects remains unclear. Future long‑term head‑to‑head trials that standardize energy intake and monitor adherence would be needed to determine whether the early weight advantage of ketogenic diets translates into sustained cardiometabolic benefit.
Source
Kun X, Roostaee A, Safarpour Lima Z, Rohani P. Comparative effects of ketogenic diets and mediterranean diets on obesity and metabolic outcomes: a systematic review and meta-analysis. Rev Endocr Metab Disord. 2026. doi: 10.1007/s11154-026-10086-x. PMID: 42766067.