You get more of an effect of alcohol on an empty stomach because you are absorbing it through your stomach, so it doesn't soak into any food or anything, it just hits you straight.

Smokin weed is a lil different, because you're absorbing it through your lungs, so the amplification of effects observed on alcohol when your stomach is empty could be compared to breathing the smoke in deeper... I guess...

On the other hand, if you were hungry to the point of fainting, it might make you a little more spaced out, but you'd probably just curl up and take a nap (after you went on a munchies-run :dance