Incretin–based therapies and protein-based dietary strategies represent two increasingly prominent approaches for fat loss in individuals with obesity, including those who engage in structured exercise. Incretin–based therapies promote weight loss primarily through appetite suppression, delayed gastric emptying, and improvements in glycemic regulation, resulting in rapid and clinically meaningful reductions in body mass. In contrast, protein-focused interventions support fat loss through enhanced satiety, preservation of diet-induced thermogenesis, and direct stimulation of muscle protein synthesis, typically producing slower but more metabolically stable changes in body composition.

For physically active individuals, the interaction between these strategies and exercise introduces additional physiological considerations beyond total weight loss. Exercise, particularly resistance training, increases the demand for adequate substrate availability to support skeletal muscle maintenance, remodeling, and functional adaptation. Importantly, these approaches also differ in the temporal pattern of fat loss, the extent to which lean mass is affected, and the durability of weight loss once active intervention slows or ceases, factors that are especially relevant for individuals pursuing long-term exercise adherence and performance.

This review synthesizes current evidence on incretin–based therapies and protein-based dietary strategies through an exercise-relevant lens, focusing on three underexamined determinants: skeletal muscle preservation, pace of fat loss, and weight-loss maintenance. Rather than positioning these approaches as competing or hierarchical, the review aims to clarify what physiological trajectories individuals may encounter when integrating each strategy with exercise. Understanding these trajectories may help practitioners and physically active individuals make more informed, context-specific decisions when selecting fat-loss interventions.