Body recomposition ("recomp") means changing what your body is made of — less fat, the same or more muscle — rather than just lowering the number on the scale. Because muscle is denser than fat, someone recomposing can look and measure very differently while their weight barely moves, which is why the scale alone is a poor way to track it; measurements, photos, strength progress, and body-composition scans tell more of the story.
On a GLP-1 the distinction matters because the medication makes losing weight easy, but a meaningful share of that weight can be muscle unless you defend it. Aiming for recomposition — a moderate calorie deficit, enough protein, and consistent resistance training — is how you steer the loss toward fat. See weight loss vs. body recomposition goals on a GLP-1 and why strength training matters.