> I'm still pretty sure that calories-in/calories-out theory is more-or-less correct. Unless someone has overturned the laws of thermodynamics, it is correct.

> I'm still pretty sure that calories-in/calories-out theory is more-or-less correct. Unless someone has overturned the laws of thermodynamics, it is correct. CICO rules over all, and it's simple but not easy to lose weight, due as you put it to psychological factors. As for the research about most people having the same metabolic rate, here's a link: http://examine.com/faq/does-metabolism-vary-between-two-people/ http://examine.com/faq/does-metabolism-vary-between-two-peop... TL;DR - almost all people of the same height and weight will be within 200-300Kcal of each other BMR wise. There are some outliers, but not enough to cover all the people claiming to be special snowflakes. And even if someone does have a "slow metabolism", that changes nothing: they still had to overeat to get fat. Mass doesn't come from nowhere.