Effect of Intermittent Fasting on Physical Performance and Exercise Outcomes: A Systematic Review and Meta-Analysis of Clinical Trials

Abstract

Intermittent fasting (IF) practices are common eating patterns among physically active population. Therefore, the possible effect of IF on physical activity should be vigorously explored. The objective was to perform a systematic review along with a meta-analysis to determine the possible impacts of IF on physical performance. From the earliest feasible date to January 2024, all of three electronic databases of PubMed, Scopus, and Web of Science were searched thoroughly. Two authors identified studies that evaluated the effect of IF on physical performance. The combined effects were expressed as weighted mean differences (WMDs) and 95% confidence intervals (CIs) implementing a random effect model. The risk of bias in the selected studies was evaluated with the Cochrane Collaboration’s tool. A total of 29 studies met the inclusion criteria. Results elucidated that IF did not exert any significant effect on some physical performance parameters including Wingate peak power output, vertical jump height, maximal heart rate, bench press 1RM, rating of perceived exertion, blood lactate concentration, and handgrip strength. Overall, our findings indicate that IF does not exert a significant impact on key physical performance indicators, including strength, anaerobic capacity, perceived exertion, or cardiovascular response to exercise. However, more studies need to be done in this area incorporating athletes from a wider range of physical fitness and diverse exercise routines.