I’ve been eating the same Subway sandwich for the last seven years. It regenerates like a starfish.
Supposedly I can never eat more than half, or it will stop regenerating. I don't know though. All I have to go off of is when I'm about a third of the way through the sandwich, I hear a delicate whisper from nowhere in particular saying, "Okay, that's enough. This is an amazing sandwich, true, but you've got to respect it's boundaries."
Part of me (the hungry part) wants to tell that whisper to go fuck itself.
["No more than half" concept courtesy of Derek Ohlms.]