Patient People: My Friend May Be Sick..?

Sick, as in eating disorder. Lately she has become obsessed with her weight. She used to be all muscle, 6 pack, when she was a nationally trained gymnast. She quit, got some meat on her bones, and now she is 100% obsessive with losing it. She runs everyday, even when she was on vacation. After running, she forces herself to do conditioning. Then at night, HUGE conditioning set. She does not snack, and fasted for two days once. But then she fainted when she went running and went home and had "some chicken". Her diet basically only consists of chicken and fruit. If there's no fruit, she has a granola bar. If she is hungry at night, I've seen, she doesn't let herself eat. She thinks eating after dinner is bad. But she only picks at her dinner anyway! She just seems weaker, more tired to do her workouts, yet she doesn't take days off. And on top of that, she got sick the other day, REALLY sick throwing up, and she still FORCED herself to run! Her legs look skinny and like ALL muscle. And when I hug her, all I feel is bone in her back and her spine pulling through. I need some support on this, to know I'm right in telling her mo and dad.