Effects of ketogenic diet on muscle mass, strength, aerobic metabolic capacity, and endurance in adults: a systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized and non-randomized controlled trials
PubMed 41035089 · doi:10.1186/s41043-025-01090-z
What was done
A systematic review and meta-analysis of 33 randomized and non-randomized controlled studies evaluating the effects of a ketogenic diet compared with other dietary interventions in adults. Outcomes assessed included muscle mass, fat-free mass, fat mass, muscle power, strength, aerobic metabolic capacity, and endurance parameters using random-effects meta-analysis.
What was found
Compared to control diets, the ketogenic diet showed: - No significant difference in muscle mass (WMD: 0.06, 95% CI: -1.97 to 2.09, p = 0.95). - Significant reduction in fat-free mass (WMD: -0.48, 95% CI: -0.73 to -0.23, p < 0.001) and fat mass (WMD: -1.31, 95% CI: -2.06 to -0.57, p < 0.001). - No significant differences in muscle power (countermovement jump: SMD: -0.06, 95% CI: -0.49 to 0.38, p = 0.80) or strength (squat: SMD: -0.19, 95% CI: -0.53 to 0.15, p = 0.27; bench press: SMD: -0.15, 95% CI: -0.49 to 0.18, p = 0.37). - Significant increase in fat oxidation during exercise (WMD: 0.13, 95% CI: 0.08 to 0.17, p < 0.001) and reduction in respiratory exchange ratio (WMD: -0.07, 95% CI: -0.11 to -0.03, p < 0.001). - No significant differences in VO2max, relative VO2max, treadmill time to exhaustion, or rating of perceived exertion.
Why it matters
This review indicates that ketogenic diets shift substrate metabolism toward higher fat oxidation and reduce body fat and fat-free mass without significantly impairing muscle strength, power, or aerobic capacity compared to control diets.
Limits
The analysis pooled both randomized and non-randomized controlled studies, increasing the risk of confounding and heterogeneity. Total participant count, intervention duration, dietary adherence, and individual GRADE outcome ratings were not reported in the abstract.
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