I used to think the same as you. I'm no longer convinced. The "afterburn" effect is, as far as I can tell, fairly minimal, on the order of 10s of calories per

I used to think the same as you. I'm no longer convinced. The "afterburn" effect is, as far as I can tell, fairly minimal, on the order of 10s of calories per day only. As for body composition, while it's true that your "calories out" increases if you add muscle, the increase is, again, negligible. Just plug in higher bodyweight numbers into TDEE calculators and see how little difference it makes. (Though they undershoot it a bit, IMO, because they don't assume that all the weight gained was muscle... it's still fairly small). The only way to lose weight is to make sure you eat less than you burn. For most people, that means eating less, and possibly adding in a bit of exercise.