[Zerook]

Apparently fasting can be healthy for some people in some cases (read something on BBC about 1 day a week fasts, and I know a few diabetics that have to fast for health reasons). But everyone else also pointed the pitfalls of it.

If it's genuine, I guess get off her back, but if you have concerns, talk to her about it. End of the day it's really up to her to make that decision though if it comes to her forming an eating problem, slap her.

Though most people collapse by the 3rd day. A lot of them employ really dubious techniques like self harm to get them through it for long periods rather than self control itself.