Sarcopenia

Sarcopenia is the loss of skeletal muscle mass together with the loss of strength and function that comes with it. The function part is what makes it matter: muscle is what gets you off a low chair, catches you when you stumble, and keeps blood sugar under control between meals. Losing it is not a cosmetic issue.

Any rapid weight loss draws on both fat and lean tissue — that is true of dieting, of bariatric surgery and of GLP-1 therapy. A 2026 scoping review of GLP-1 receptor agonists in older adults put the concern plainly: these drugs produce effective weight loss, but concomitant muscle mass loss is common, and data on muscle indices and physical performance remain limited and inconsistent. The review also noted potentially favorable effects on muscle metabolism and mitochondrial function, so the picture is not uniformly bad — it is unresolved.

What that uncertainty means in practice is that the mitigation is worth doing even though the risk is not precisely quantified, because the mitigation is good for you regardless. Two interventions have the strongest general support: enough dietary protein spread across the day, and resistance training. The National Institute on Aging describes strength training as one of the core exercise types for maintaining muscle and independence with age.

The common confusion is reading a lower number on a body-composition scale as proof of harm. Consumer bioimpedance devices estimate lean mass poorly, and lean mass includes water and glycogen, both of which shift early in weight loss. A better real-world check is function: can you still do the same number of sit-to-stands, carry the same load up the same stairs, hold the same grip?

Worth asking your clinician: what protein target fits your weight and kidney function, whether resistance training two or more days a week is safe for you, and how strength should be tracked over time. Our muscle-loss prevention protocol, protein calculator, exercise pairing configurator and older-adult evidence page cover the plan.