It's the ignorant and the jealous who popularize the myth that the anorexics are girls who want to be pretty. (It disgusts me to be honest.)
Anorexia is a symptom and never the case. The case could be most unimaginable thing in the world.
An example from a culture history book I read just this morning:
"Example of one of Rat Man's obsessive activities also displays potential of psychoanalytic reading. One summer, when the Rat Man was on vacation, he couldn't get out of his mind the obsessive idea that he was too fat and that he had to lose weight. He began running for long distances, climbing harsh mountainsides and skipping dessert in order to lose weight. One session with Freud produced a productive chain of associations for the Rat Man. The German word of fat is dick, which was also the name of an American cousin of his. It emerged that his cousin Dick was paying attention to a young woman with whom the Rat Man was also infatuated. When the Rat Man was trying to get rid of his fat he was really trying to get rid of his cousin - in his harsh punishing work-out regime he could be seen to be punishing his cousin as well as himself"
Another, real life, example was when I myself lost appetite for everything - food, sleep, life - because I thought I was no good at painting and didn't have a chance to improve either. It was my way of punishing myself when I thought I didn't have any right to live and waste space. The real case behind it was that I had a teacher, who didn't know me yet because it was the beginning of semester, but to whom I had already gained respect and trust (I still trust her; maybe she's even the person I trust most in this world). During one of our lessons, she was walking along our easels and giving opinions, mostly consisting from both critiques and compliments, but when she stopped at mine she gave me a lecture. About how bad, disgusting and pathetic my work was. How I worked only for the mark. I must be the kind of student that always gets the top marks (I couldn't deny that), she said she saw right through me and she knows I don't work for myself, I don't even try, I just use a recipe that works.
Then was the break call I went to bathroom to cry on my own (I couldn't hold it although I hate it when it happens), came back after five or ten minutes trying to act as pulled-together as I could. In these kinds of situations I can't tell reality from my own sentiment, but I discovered the whole class was absolutely shocked, so I guess it was pretty bad for real.
Returning to the fact how it affected by behaviour, I don't dare to think what would have I become, but later my class stood up for me (since the teacher kept on bashing every single lesson) and it helped a lot. I got better, alas lost any interest for painting (it used to be my favourite thing), I started skipping lessons too. It all changed to good when teacher suddenly changed her opinion about me completely, by 180°, she just started not liking me, but loving. It drove me mad, I couldn't understand her. Perhaps she talked to other teachers who knew me better. I don't know. To sum up I can say that it feels like a long time since this although it's been less than a year and a half since then.
I had utterly forgotten about this in details, sorry for such a long example, but real life experience isn't easy to tell clean-cut.
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As for the will-power to be thin: bloody fucking hell, don't be such a baby! What is this television age quote when people just look at what others do and just wish, but never do anything about it!
How they try to diet and then slip and at the moment think: I wish I had the will-power to stop. And ,girl, that is your will power you are not using at the moment! It is not an abstract thing. Will power is self-control when you don't feel like it. It's never easy and if it is, it's either from having nothing to overcome or out of habit.
Don't you all miss the time when society wasn't mental illness paranoid? When dieting was normal and it was almost an every day common thing if a girl skips meals to lose weight? Because all 90's films and magazines are full of this stuff. Diet is even a cliché cool thing to do for a teenager/young woman.