Ok firstly there are the health problems to consider.
You want to get to 30 and have to have your hips replaced because you have malnutrition-related osteoperosis? Have to be on crutches and take steroids for the rest of your life for the pain?
Secondly, infertility. Want kids? Sorry, you have to eat! Your body fat drops below a certain level, you stop getting periods, and eventually your body eats your womb for nourishment.

Secondly, superficial stuff.
Very few people want to shag a bag of bones. Women are meant to be 'squishy', it's natural. Boobs and a bum are great, believe me, clothes look better with some shape.
Every aging process is speeded up by anorexia. You'll lose the elasticity of your skin. I mean, eww!
Your hair will thin.
You will get lanuga, downy fluff on your back and arms, maybe your face, as your body tries to keep you warm. Does shaving your back really appeal?

A girl who is fussy about her food is not a happy girl or a fun girl. No-one wants to take someone out to dinner for them to just pick at a salad.

Food is a pleasure. Doesn't mean eat chocolate all the time or pig out, but it's not something to be fearful of or obsessed with.

Are you overweight? Or normal weight, or underweight?
Being unnaturally underweight is BAD. Some people, for example crimsonnyte on here, is naturally underweight, but she's not unhealthy because that's just the way her body is.
Everyone's body is different, and has a different 'ideal weight'. Not ideal in your head, ideal for your body to perform at its best. Depends on body type, body build, height, muscle- all sorts.
If you're overweight or used to be you're doing the worst possible thing for your body ever. And I'm saying this because I know, I've been there, so I'm not talking out of my arse.

If you want to PM me then I can talk to you in more detail and maybe give you some guidance as how to change your habits and recover, but it has to be because you want to. Consider it.
I know a lot about this, and I'm not going to treat you like you're stupid or dumb, so give it some thought and if it's something you'd like to explore, give me a buzz.