text: in what way do cigarettes and caffiene effect metabolism?   well they get my butt going in the morning.  nicotine is a complex drug.  if you need to be up it will help you pick up and if you need to relax it helps you relax.   basically it magnifies the feelings and emotions that you are trying to get.  caffine is a stimulant and diuretic so if it doesn't get you going mentally it will get you going "pee" wise.  the combination of the nicotine and caffine are real morning starters, that jump start a person and get them going faster.  metabolically i would guess it would speed up that as well since it seems to be the same effect on every other system.