Additional Effect of Exercise to Intermittent Fasting on Body Composition and Cardiometabolic Health in Adults With Overweight/obesity: A Systematic Review and Meta-analysis

Objective: The purpose of this study is to evaluate the additional effect of exercise to intermittent fasting (IF) on body composition and cardiometabolic health in adults with overweight/obesity.

Method: Relevant studies were identified through a systematic search across five databases. A random-effects meta-analysis was conducted on outcomes including body composition and cardiometabolic health markers, to compare the effect of combining IF with exercise against IF alone. The certainty of the evidence was evaluated using the GRADE approach, while the quality of the included studies was assessed using the revised Cochrane risk-of-bias tool and the TESTEX scale.

Result: In total, twelve studies including 616 participants (Age: 40 ± 9 years; BMI: 33.6 ± 4.8 kg/m2; 87.3% female) were included in this systematic review and meta-analysis. The combined intervention was more effective, leading to greater reductions in fat mass (-0.93 kg [95% CI: -1.69, -0.18]) and waist circumference (-2.51 cm [95% CI: -3.70, -1.32]) when compared to IF alone. Cardiometabolic health parameters also showed greater improvements, with decreased insulin (-3.1uIU/ml [95%CI: -4.25; -1.95]), HOMA-IR (-0.57 [95%CI: -0.83; -0.31]), LDL (-10.67 mg/dl [95%CI: -20; -1.35]), resting heart rate (-2.68 bpm [95%CI: -4.71; -0.64]), along with enhanced cardiorespiratory fitness (VO2 max:1.92 ml/kg/min [95%CI: 0.32; 3.52]). For the remaining outcome variables, no statistically meaningful differences emerged between the groups.

Conclusion: The potential benefits of incorporating exercise into IF for adults with overweight/obesity, particularly in terms of body composition, glycemic control, and cardiorespiratory fitness, appear promising. Nevertheless, given the limited amount of data, future investigations are essential to strengthen the evidence base and investigate the influence of specific exercise and IF types in enhancing treatment outcomes.