Skeletal muscle is more than movement—it’s everything. Your muscle mass determines how well your body regulates glucose, burns fat, and withstands illness. After a meal, ~80% of insulin-mediated glucose disposal occurs in skeletal muscle. Without sufficient muscle mass or function, excess glucose lingers in circulation, driving metabolic dysfunction. At rest, muscle primarily oxidizes fatty acids. This metabolic flexibility—the ability to shift between using glucose and fat efficiently—defines a