Honestly I'd have done nothing whatsoever. There is always the chance that said guy *needs* that food, but there's also a chance of danger... not just for you, but for the employees. And I guarantee you, that guy stealing something aint gonna matter to the actual employees (unless said employee is literally security, then it does matter, of course).
Heck, I remember working for Toys R Us many years ago (one of the good ones, lovely place, as you might expect) and there was a situation where this guy was in there, CLEARLY shoplifting. And he wasnt just taking any old thing, no. He was taking "difficult" products... you know, the ones that are in funky "packaging" meant to secure the product until the cashier could scan it and then take it off for you.
We were all warned about this guy at the same time once he was noticed, but were explicitly told NOT to engage. If he comes near? Get away, dont engage. Engaging could be very dangerous, dont dare do it, they said. Just watch, and calmly report if you spot him, so we can all keep track of where he is.
The problem with telling employees about this sort of thing happening is that someone might try to DO something about it, is what I'm getting at. And the something that "gets done" could end up getting done to the employee, not the other way around, when they try to play hero. It really is best to just not get involved.
Besides, I guarantee you, it aint gonna do anything at all to the company itself.