I think you're mistaking: anorexia is the exact opposite; it is a disorder which effects the person's appetite in a negative way—that is to say, they may eat less than the norm, not more.
NOO! Anorexics are obsessed with food because they want to have complete control over bodies and consequently, their caloric intake. It becomes the most important thing in their lives so they think about food all the time. Plus wouldn't you think about food alot if you were starving all of the time?