kneebrace

It seems to me that you have changed your argument from 'a calorie deficit is always required' to 'a calorie deficit is only required when your weight is close to goal'. I can live with that, since that seems to be what happened to me. But your first argument may be correct if metabolic advantage exists.

I'm a believer, because I can't think of another way that fat can disappear from the face of the earth so fast. The mechanism is unknown and can hardly be imagined without invoking magic. However, if you google uncoupling proteins especially in regard to high fat diets, you can see a nice mechanism where your mitochondria could become very inefficient at converting the chemical energy of food into the metabolic energy of ATP. If you open up the accessory proton gates of the inner mitochondrial membrane, and allow the proton gradient to leak back across without going through ATPase, you've effectively wasted all the food energy as heat, or light, or rap music, or whatever, and gotten minimal ATP out of it. I suspect that's how it works. It would be nice if someone actually researched it a bit, and ran some numbers...

So all you need to do is change the "macros", set a new set point, and metabolic magic does the rest, no matter how much you eat.

At least in the lucky few of us who are "exceptions"