Aggh that word is so triggy, thinspiration. It's what some people I know used to call the pictures of models they would look at.
Anyway ... the way I've seen it, there are two types of "starvers/purgers" if you will. Not to be offensive (I myself have starved and do still occasionally do so, so ... how can it be offensive if I am referring to myself). Anyway. There's the ones who want to fit into a size six, do the drill for a few months, fit into size six and then stop. Or who go a few weeks down the path, decide it's too hard and stop.
These people don't have the "switch" for the eating disordered mind set, in my opinion. They see it as a fad diet. Which is sad and kinda screwed up, really.
Then there's people who do this for whatever reason - usually control, but sometimes to lose weight for fitting into a size six - and something in their head twigs. The switch flips. And it becomes a full blown eating disorder which is HELL to go through and the switch never fully unflips.
These people have far deeper reasons for not eating - whether it's a mood disorder or something that went really wrong in their lives.
I don't know how to tell her it doesn't matter what she looks like, other than to tell her how amazing and adorable and what-have-you you all think she is. Show her articles about how badly this can damage her body and
this memorial to people lost to eating disorders. Find the horror stories of the girls whose stomachs quite literally exploded while they were purging, to be found in their underwear, bloated, on the bathroom floor, and show them to her.
If she's doing it for a fad or the switch hasn't flipped yet, she'll soon realize it's not worth it.
If the switch has flipped ... you'll need some serious intervention to get her to stop.
*hugs* I wouldn't wish this hell on anyone. I wish people would stop seeing it as a quick fix to get thin, cause that it isn't.