> it's too late. Their metabolic system has been compromised by either diet, hormones, genetics, whatever.

I do want to be clear to anyone reading: there is no "too late". One's system does not become somehow damaged at some cliff of weight and eating habits. It doesn't become irreparably meaningfully physically more difficult to lose weight. What can happen is a shift in many systems that effectively make one feel hungry all the time and psychologically react very strongly to those hunger cues, which makes people eat more. Outside rare circumstances, if you eat less, you will lose weight. I do have a lot of compassion for the psychological side of things being extremely difficult, though.

Sorry - I think there's complexity with insulin at play that you're overlooking. When I did caloric restriction, I was constantly battling hypoglycemic events that made me not want to exercise. I don't get that with the GLP-1s. In online discussions, people tend to conflate GLP-1 with appetite suppressants - but there's also insulin stabilization that occurs.