just don't go over 90 min on the bonk without food or else your body will start digesting the muscles... and well, that's a bit self-defeating there
as to it being a diet, uh, no. you're not supposed to be skipping b-fast, nor is it really a "diet" since it's not restricting any intake whatsoever. the caffine thing is optional, tho some med. research has shown that coffee 30min. before any activity makes your body burn more fat (but so does stretching :P)