Effect of resistance exercise on body composition, muscle strength and cardiometabolic health during dietary weight loss in people living with overweight or obesity: a systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 40909191 · doi:10.1136/bmjsem-2024-002363
What was done
Systematic review and meta-analysis of randomized controlled trials searching PubMed, Embase, CINAHL, Scopus, Web of Science, and CENTRAL. The authors included 25 trials examining adults aged 18 to 65 with a body mass index of 25 kg/m2 or higher to compare diet-induced weight loss plus resistance exercise against diet-only weight-loss interventions. Study quality and certainty were evaluated using the Cochrane risk of bias tool and GRADE framework.
What was found
Adding resistance exercise to dietary restriction had no significant effect on total body mass loss compared to diet alone (mean difference: -0.32 kg, p=0.35; weight loss ranged from -2.5 to -20.9 kg in diet plus exercise groups vs -0.7 to -20.4 kg in diet-only groups). However, resistance exercise protected against fat-free mass loss (standardised mean difference [SMD]: 0.40, p=0.0003, moderate certainty), increased fat mass reduction (SMD: -0.36, p<0.00001, high certainty), and improved muscular strength (SMD: 2.36, p=0.00001, low certainty). No significant effects of resistance exercise were observed for other cardiometabolic markers.
Why it matters
This meta-analysis confirms that while adding resistance training does not alter overall weight loss on the scale during a diet, it significantly improves the quality of weight loss by preserving lean mass and increasing fat loss.
Limits
The total number of individual participants was not reported in the abstract. Certainty of evidence for muscular strength was graded as low, and the intervention had no demonstrable impact on cardiometabolic markers. Specific exercise modalities, dietary interventions, and adherence levels were not detailed in the abstract.