How can I convince my anorexic friend to eat?

My friend isn't technically clinically anorexic because she just got this eating disorder within the last few months and hasn't become emaciated "enough" to be considered "anorexic". However I don't want her to become that way and she needs to eat, she barely eats anything and then makes herself vomit up her one meal a day. People just found out that she's doing this to herself, but because she's not underweight yet the response has been rather slow. Any tips on how to get her to eat?