They should put the kids through physical training, the same sort the military goes through, then grade ‘em on performance. The goal, of course, would be to train them up to military physical standards and better.
It would be good for the kids and good for the country.
I don't trust the BMI thing. There are just too many body types out there. I realize the issue is to deal with childhood obesity but I think there is too much lack of common sense in our schools to carry such a program out.
Two examples: I had a friend who was 6' 4" and really an "Amazon" type woman in regard to bone structure etc. She joined weight watchers (which I support btw) but their scale of appropriate weight for her was totally ridiculus and out of whack for her body type. Second: I have a nephew is looks perfectly normal in regard to weight and heighth. But you try to pick the kid up and he is as heavy as an anvil. I guess he is just really dense. And just for fun a third: It never fails that when I tell people what I weigh they say, "no way!". I've always downed myself because of my weight until finally a Dr. told me they don't consider me overweight...even though on their "scale" I don't fall in the weight range for my age etc.
Nanny staters are nanny staters. Your goal is different, but still devalues individual liberty.