But what is "metabolism"? It's just a catch-all word meaning that some people can eat more than others without getting fat. It's not a process, it's just an ideayou said you think metabolism is a myth and then gave a list of things that don't make sense unless there's some process to explain them...which would be variable metabolism from person to person
Say yourself and myself sit down in a room together and eat 3 big mac meals and only 3 big mac meals a day for a month. If, at the end of it, you're fatter than me it means either you're digesting your food better than I am and getting more energy out of it, or else I'm somehow burning more energy than you by just sitting there. If I am, and my body temperature is no higher than yours (which it probably isn't), then where is that energy going?
That's what kinda puzzles me about the idea of metabolism - where's the energy going?