So many children live in places where it's not safe to get out and run around, though, Caribou. Or they have to go to a CM after school, or to an after school club. When the majority of parents work and the majority of school age children are not going straight home where they can either play with siblings or be available for friends calling around to play, a situation develops where many children spend many solitary hours after school. In addition, many do not have a garden, or access to a leisure facility (or the wherewithal to pay for same).
If schools are serious about health they need to schedule PE more than 2 hours a week.
And believe it or not, there are millions of children who are very picky. I was very lucky that my very picky children would eat a slice of deli ham or turkey in a whole wheat sandwich. I felt that they were getting a little nutrition along with nitrates, nitrites, and goodness knows what else goes into your average slice of American deli meat. There were children who wold only eat white bread and the substance known as 'American cheese'.
I was also lucky that my DCs' school was not required to police lunchboxes, that the school ran a very well subscribed extra curricular sports programme - cross country running in August-September, followed by co-ed soccer in September-October, followed by basketball from October to the end of March, with volleyball after that until the end of May. Most children played at least one sport. In high school they had PE every day for 50 mins.