Effects of Exercise Interventions on Weight, Body Mass Index, Lean Body Mass and Accumulated Visceral Fat in Overweight and Obese Individuals: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

(1) Background: Exercise interventions for overweight and obese individuals help reduce accumulated visceral fat, which is an indicator of cardiometabolic risk, but the effectiveness of these interventions is controversial. The purpose of this meta-analysis was to investigate the effectiveness of exercise interventions in overweight and obese individuals in order to reduce weight, body mass index (BMI), and accumulated visceral fat, and increase lean body mass. (2) Methods: Databases were used to select eligible studies for this meta-analysis. Randomized controlled trials with control and experimental groups were included. The degrees of effectiveness of the exercise interventions were computed to assess the benefits on reducing weight, BMI, and accumulated visceral fat, and increasing lean body mass. (3) Results: Sixteen studies were included in this meta-analysis. Participation in exercise interventions reduced weight (d = -0.58 (95% confidence interval (CI), -0.84--0.31; p < 0.001; k = 9)), BMI (d = -0.50 (95% CI, -0.78--0.21; p < 0.001; k = 7)), and accumulated visceral fat (d = -1.08 (95% CI, -1.60--0.57; p < 0.001; k = 5)), but did not significantly increase lean body mass (d = 0.26 (95% CI, -0.11-0.63; p = 0.17; k = 6)). The average exercise intervention for overweight and obese individuals was of moderate to vigorous intensity, 4 times per week, 50 min per session, and 22 weeks duration. (4) Conclusions: Participating in exercise interventions has favorable effects on weight, BMI, and accumulated visceral fat. Further studies considering different modalities, intensities, durations, and measurements of fatness need to be conducted.