Resistance Exercise Optimizes Body Composition During Incretin-Based Weight Loss Therapy

Incretin-based pharmacotherapies, such as GLP-1 receptor agonists, have revolutionized weight loss management for conditions like obesity and type 2 diabetes. While highly effective at reducing body weight, a significant concern is the potential for concurrent loss of lean muscle mass alongside fat, which can negatively impact metabolic health and physical function. This study hypothetically investigates whether combining resistance exercise with incretin pharmacotherapy can optimize body composition by preserving or increasing lean mass while maximizing fat loss.

Both groups achieved significant total body weight loss, averaging 12% of baseline body weight. However, the combination therapy group demonstrated markedly superior body composition changes. The group combining semaglutide with resistance exercise experienced a 2.5-fold greater preservation of lean muscle mass compared to the drug-only group (p<0.001), indicating a more favorable shift in body composition. Specifically, the drug-only group lost an average of 3.5 kg of lean mass (a 5.2% reduction from baseline), whereas the combination group lost only 1.4 kg (a 2.1% reduction, p<0.01 between groups). Fat mass reduction was substantial and comparable between groups, with 15% vs. 16% total body fat reduction, respectively. Furthermore, the combination group showed a 1.2-fold increase in overall muscle strength, while the drug-only group experienced a 5% decrease.