Synergistic Effects of Combined Diet and Exercise on Body Composition in Adults: A Systematic Review and Meta-Analysis

Abstract

Introduction: Obesity and poor body composition are major contributors to chronic disease risk in adults. This review aimed to compare the effectiveness of exercise-only, diet-only, and combined interventions in improving body composition outcomes. Methods: A systematic review and meta-analysis were conducted based on studies published between 2016 and 2024 from Scopus, Web of Science, and ScienceDirect. Forty-six studies involving 3,429 adults across five continents met inclusion criteria. Quality appraisal followed PRISMA and MMAT guidelines. A meta-analysis using RevMan 5.4 included six eligible studies. Results: Combined interventions resulted in the most consistent improvements in body mass index (BMI) (SMD, −1.74; 95 % CI: −3.07 to-0.40; P =.01), body fat percentage (%BF) (SMD, −2.40; 95 % CI: −2.91 to −1.88; P