Exactly. With anime, you have to take it with a grain of salt as they say. I rather hear it from a more reliable source for learning about culture, although I do know that Japanese schools are a lot stricter than North American schools, so it wouldn't surprise me.

People put WAY too much emphasis that thin is healthy, when it's not. Like you said, you need to have a healthy body, being one of the two extremes isn't healthy. (Although, it's funny what each culture considers to be beautiful. I remember once watching a program about a small country, in Africa I think, where over weight women were considered the ideal women and you can imagine they have a lot of health issues there too.)