Isn't it obvious - you BMR is 2-3 times higher than your all other energy expenditures for the day. If you overeat nothing can save you ...
It's not obvious, actually; exercise also affects the BMR, as a matter of fact, according to some theories, certain types of exercise increase the BMR more than certain others (I don't express any support for this, just pointing out). Although we're not talking about huge amounts, when having a precise dieting regime, even a few hundred calories of "good weight loss" matter. Definitely nothing can save one from overe…
And you have upper limit on your BMR - you have to maintain a steady temp. We just cannot dissipate much more than currently before cooking ourselves medium rare.