I don't see whats so bad about teachers teaching their kids to become healthier. America is known for being obese. How is it only the parent's responsibility to make kids healthier? I don't see anything wrong with the school giving their kids a proper education to be fit and healthy.
There is absolutely no reason why generally useful knowledge should not be taught in schools. I have no idea how anyone could reason against that particularly because the entire reason you send your children to public school is to learn generally useful knowledge that will be utilized later in life.
With the world getting more fatter each day is nutrition in school any good or is it a waste of time you see we believe that nutrition is not a bad thing but that parents are being lax and thinking just because they are being taught in school they don't need to teach their children what to eat. The problem is that schools may not be teaching them the right things. So that it should be stopped as a lesson but still encouraged as a daily habit.