Get the kids interested in sandlot sports again and they will be healthy again. In the summer I remember leaving the house at 11am going to the park and playing football, baseball, or basketball whatever was "goin on" that day and not coming home till like 6-8pm looking for dinner. Today kids sit at home all day eat and play video games.
I don't know about other places; but in my area, kids aren't aloud to play on the fields unless they have a permit from the town or county.