As someone who used to make myself throw-up, I can say that it really doesn't work.
In the very short term -- like a day, yes, it makes you feel like you can eat and then not gain any weight, but it doesn't have any effect on the long term and it can cause problems to your insides and the larger problem is a mental one -- that even once you have done it, you don't get the results that you want. I was just talking to a friend about this -- and we both agreed that you just reach about 25 and realize the assets that you have. I also just saw Eve Ensler's play The Good Body -- all about our issues -- and I don't think that anything can change us, but ourselves.
I hope you get to this place.