We're told losing weight is a matter of willpower, that semaglutide solves the problem, and that fruit fructose is the same as soda fructose. The reality is metabolic: endogenous GLP-1, insulin, leptin, microbiota, lean mass. Ten questions, a few traps, few mantras. Level 1: willpower and calorie deficit as the only explanation. Level 2: metabolic confusions — fruit fructose versus soda fructose, lean-mass loss on GLP-1 analogues, high but ineffective leptin. Level 3: what happens when treatment stops, and why gut microbiota and muscle mass decide what comes next. Sources: NEJM, Cell Metab, Nature. See our terms and conditions. The information shared here does not replace advice from a qualified health professional.