Make sure to save any documentation you have to prove that you had no money at the time, like an dated overdraft notice from the bank, or something of that nature. If you have to call the bank and have them print out something showing your card had a hold on it, or whatever, do so.
It might be worth noting that they may look more favorably if this is presented as a situation where you've never had this happen before, never been homeless before or anything like that, and therefore scared and unsure of what to do. Someone who has never had to go beg for change or go to a shelter and ask for food, probably doesn't think of that as their first option when they're hungry, and lets face it, the majority of americans have no idea what real hunger is like so they tend to be pretty unsympathetic or ignorant until they experience desperation personally. It's not unusual for a middle class family to be struck by a major financial disaster and find themselves suddenly poor, and have no clue what to do or where to go for help and almost in a state of disbelief that this could be happening. Like someone else said, it would also probably look better if you stole real food, and not candy bars or something like that.
Also second on the asking for a public defender. Can't you request legal counsel be provided BEFORE you have to make your plead? If not that's rather screwy, how is Joe Average supposed to know how they should plead?

