In my opinion, food is like mundane ammunition: it's not important enough to track, unless it is.
Let me explain. If your adventuring group is making occasional, brief forays from a major town or city, then there's no need to track food and arrows. Just have everyone buy that stuff *once*, and assume it's being replenished as needed. In this situation, tracking mundane items like arrows and food is pointless and not fun.
If, however, the party is making a long trek across a wasteland, or is in siege situation, or at sea, or otherwise cut off from fresh supplies... then start tracking each arrow shot, each pint of water consumed. In this situation, part of the drama/fun of the situation is that supplies are running out. It's the "survival horrow" scenario, where sure, the hero can just blast the monster with his shotgun... but that'd be his last shell, and there are plenty of other monsters out there.
-z