Do GLP-1s work without diet and exercise?

Strictly speaking, the medications do the heavy lifting. In trials, participants received standard lifestyle counseling (a mild calorie target and activity advice), and adherence to it was ordinary — yet average losses reached 15–21%. The drug’s appetite suppression creates the calorie deficit whether or not you exercise. People who cannot exercise due to joint pain or mobility limits still lose substantial weight, and for many of them the loss is what finally enables activity. The honest caveat is body composition. Weight lost through pure calorie deficit is typically 25–40% lean mass unless you actively defend muscle. On a GLP-1, where eating drops effortlessly, the two defenses are: 1. A protein floor — roughly 1.2–1.6 g/kg of goal body weight daily (details) 2. Resistance training 2–3× weekly — even brief, basic sessions Skip both and the scale still falls, but you arrive at goal weight with less muscle, a slower resting burn, and a harder maintenance job. Exercise on a GLP-1 is not about creating the deficit — the drug does that — it is about deciding what the deficit burns.