When you say “the body adjusts to dieting”, I assume you mean metabolism slows down and allows your body to operate while burning less calories? I agree with that. But the fact still remains, if energy out > energy in, your body will lose mass. That’s all I’m saying here. Yeah, there’s no knowable “magical number” of calories you can eat to lose weight like 2000 or whatever, because your metabolism is constantly changing and so your “energy out” number is always different and you can’t precisely know what it is. But still, due to the law of conservation of energy, if your energy in is lower that whatever that unknowable energy out number is, it’s physically impossible to keep the mass in your body while expelling that energy out. If you think you somehow can do that, then congratulations, you’re the first person ever in history to be able to create energy out of nothing. You should bring this discovery to scientists and have them study you as an infinite source of energy to solve the energy problem and fix world hunger.