[tonysdg]

Presumably (and I'm partially speculating here, since it's not my expertise) because all of the neurotransmitters, hormones, etc. pay heed to the same laws of thermodynamics that everything else does.

Your genes may influence how many calories you burn, the foods you eat may influence how full you feel, your hormones may influence where fat develops and disappears -- but thermodynamics require that if you expend more energy than you take in, the difference will have to come from somewhere, and that's ultimately how weight loss works.

[tomhoward]

Yep, I acknowledged that in the last sentence of my comment.

My point is it's not at all simple, and it's certainly not as simple as the "calories-in/calories-out" mob claim. If it were so simple, obesity, diabetes and other metabolic disorders wouldn't be the widespread and profound problems that they are.

And my larger point is that the "calories-in/calories-out" call is a euphemistic way of trolling people who suffer these conditions.