HN-02100190_Effect of Alternate Day Fasting on Resting Metabolic Rate and Body Composition in Overweight/Obese Individuals

Introduction: Alternate-day fasting (ADF) has become increasingly popular, yet, to date, there is not enough evidence regarding its effect on resting metabolic rate (RMR). The aim of this study was to compare the effect of ADF on RMR and body composition with calorie restriction (CR) diet in overweight/obese subjects.Methods: This semi-experimental clinical trial was conducted on overweight and obese adults (18 to 45 years old; BMI 25-39 kg/m2). Participant were randomized into 2 groups: ADF (25% of energy needs on ‘’fast’’ days; 100% of energy needs on alternating ‘’feast’’ days) and calorie restriction (75% of energy needs every day) for 8 weeks. Body composition and RMR were measured before and after the study. Physical activity level was estimated using pedometer.Results: The change in body weight for ADF group was 4.92±2.59 vs 2.95±1.60 kg for CR group (P<0.001) during 8 weeks of intervention. The mean percentage body fat significantly decreased (1.39±2.20; P<0.001) among ADF group while the change was not significant among CR group. Interestingly, the mean changes of RMR increased in ADF group (211.45±191.8 kcal; P<0.001) while it decreased (170±135.42 kcal; P<0.001) among CR group.Conclusions: ADF may produce greater improvement in body composition, fat distribution and RMR compared to daily calorie restriction. ADF may be recommended as a solution for preventing metabolic decline through the weight loss program.