We have a fat cat too. He is definitely my favorite.

I call him Ol' Fatass. I'll shake the treat baggie and he's the first one to come panting out for one. He'll eat food and drink water til he throws up everyday. It's really sad to see him so unhealthy...the other cats are fine. I don't know why he eats like that. It's not munchies either, he doesn't like to smoke with me...