Concerned for my friend?

My friend is currently trying to lose weight and she started yesterday. I think that's great and all, but I'm kinda concerned. She says she never eats breakfast, but I thought breakfast was the most important meal of the day? And today for lunch she brought only an apple and water and I never saw her eat the apple (she might have ate it later thought). The thing is she is only 12 and I'm just concerned she might be going a bit overboard. Maybe I'm just overreacting?

Also, not to call her fat or anything, but I think it would do her good to lose weight. I'm just telling you this so you know she's not just doing this because she "thinks" she needs to, I believe she "knows" she needs to lose some weight.