I don't think it's an actual diagnosis (as in, one that the medical/psychiatric community recognizes) but it's been called "Fatorexia". It's amazing the lengths the obeast in the article went to in order to hide the truth from herself. She was nurturing her own delusion. I'm sure she can't be the only fatty doing it, either. It explains why they always have a pound of make-up and fake fingernails, but can't be bothered to put down the fork and get on the treadmill.