Something like "you feel a pang of hunger .. that uncursed orc scorcher corpse looks tasty." (If there is one in your inventory, or if no corpse is in your inventory, something like this is triggered when you walk over the corpse.) ..just a thought.
Probably a message that only needs to appear once in any game? The message could stop appearing after x corpses have been eaten? (Though if it only appears once in a game, I'm not sure if there needs to be a counter to kill the message entirely.)