Purpose This meta-analysis evaluated the effects of exercise combined with intermittent fasting (EX + IF) on body composition, cardiometabolic health, and muscle performance in adults and examined potential moderators. (2) PubMed, Web of Science, Embase, and the Cochrane Library were searched, and reference lists of eligible studies were screened. Effect sizes were calculated as Hedges’ g . A three-level random-effects model was fitted using the metafor package in R, with moderation and meta-regression analyses conducted to identify influential factors. Results Sixty-five randomized controlled trials (RCTs) including 3,293 participants (18–75 years) were included; 42% were overweight/obese and 11% were trained individuals. Compared with control conditions (exercise alone, intermittent fasting alone, or neither), EX + IF significantly reduced body mass, body mass index, body fat percentage, fat mass, waist circumference, and visceral fat, with no significant effects on fat-free mass or lean body mass. For cardiometabolic outcomes, EX + IF reduced total cholesterol, triglycerides, low-density lipoprotein cholesterol, and interleukin-6; improved fasting blood glucose, fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR); and modestly increased VO 2 max. Multivariable meta-regression indicated maximal effects with 45–60 min per session, 4 sessions/week (230–300 min/week), over 14–30 weeks (cumulative training time 7,463–8,592 min). Conclusion EX + IF improves body composition in adults, benefits selected lipid and glycemic markers, and enhances cardiorespiratory fitness. Based on current evidence, it may be particularly suitable for middle-aged adults with overweight/obesity whose primary goals are weight loss and improved insulin resistance (45–60 min/session, 4 sessions/week, for ≥14 weeks). Systematic review registration https://www.crd.york.ac.uk/PROSPERO/view/CRD420251131430 .
Jiao et al. (Tue,) studied this question.