Anorexia, willpower, self-control, etc.?

first off, do not yell at me for "wanting" an eating disorder or whatever; that's just stupid. i've always wondered how someone can go so long with eating so little. like.. the self control that is put into that is admirable... am I missing something?! how can you do that? x_x don't tell me " oh, they just think they're fat, etc.," intelligent answers, maybe? my question is hardly a question.