Effects of intermittent fasting combined with resistance training on training adaptations: an exploratory multilevel meta-analysis.

Background: Intermittent fasting (IF) is increasingly combined with resistance training (RT), yet its effects on RT-specific adaptations remain unclear because previous reviews have mainly focused on body composition and metabolic outcomes. Objective: This exploratory multilevel meta-analysis compared IF combined with RT versus RT alone for training adaptations, including maximal strength, local muscular endurance, hypertrophy-related outcomes, and explosive/high-speed performance. Methods: PubMed, Web of Science, and SPORTDiscus were searched to 10 March 2026. Eligible studies were peer-reviewed English-language randomized parallel-group or crossover interventions comparing IF plus RT with RT alone for at least 4 weeks in generally healthy participants. Risk of bias was assessed using the Cochrane Risk of Bias 2 tool. Hedges' g values based on between-group change scores were pooled using multilevel random-effects models with cluster-robust variance estimation. Results: Eleven studies involving 303 participants were included. Participants were mostly young adults, with varied training status and body-composition profiles. Interventions lasted 4 weeks to 12 months, most commonly used time-restricted eating/feeding, and generally matched RT programs between arms. IF plus RT produced broadly similar training adaptations to RT alone overall ( Conclusion: Current limited evidence does not indicate that IF combined with RT clearly compromises chronic RT-related adaptations when RT and nutritional support are reasonably maintained. Further well-controlled research is warranted.