Basically the title, she doesn't eat at all unless her parents force her to eat something.

She told me she doesn't want to eat because it "will make her fat". I tried talking to her that it is not healthy and that I'm concerned about her, but she just ignores me about this and repeats "i just don't want to eat :)))". She is already underweight (thankfully not too much though)

I really want to help her, but I have no idea how. Any tips what can I do to help before it's late?