Intermittent Fasting May Enhance Resistance Training Effects on the Body Composition of Obese Males, Without Affecting Muscular Strength and Anabolic Index

Purpose This randomized controlled trial aimed to evaluate the impact of intermittent fasting (IF) during resistance training (RT) on body composition, muscular strength, and the testosterone:cortisol ratio in obese males. Methods Twenty obese males (aged 20–30, BMI 30–36 kg/m 2 ) were selected from eligible volunteers and randomly assigned to control (regular diet) and IF (4:3 IF) groups. All subjects participated in RT 3 days/week for 8 weeks. Forty‐eight hours before and after the protocol, blood sampling and anthropometric measurements were done in a fasting state, and data were analyzed at a significance level of p < 0.05. Results The IF/RT group lost twofold more weight and fat, had higher arm and chest measurements, and had less waist circumference than the C/RT group. The testosterone levels and muscle strength improved with RT, and there was no difference between the C/RT and IF/RT groups. Conclusion It appears that intermittent fasting may enhance the efficacy of RT in obese males and is unlikely to have any detrimental effects on muscular strength or the anabolic index. Trial Registration: Iranian Registry of Clinical Trials (IRCT): IRCT20190213042702N4