Luckily, just like Nethack and other roguelikes, you’ll be able to eat the corpses of enemies such as rats. So if they eat everything in the dungeon, you’ll still have food lol! (This is sort of supported already - I’ll make it so that enemies spawn a BP_FoodActor, which can be picked up and eaten to regain food or starvation values).
(Note that it is somewhat ill advised to eat any old corpse, as they may carry disease and cause your character to be sick!)