Elementary schools should schedule their lunch play times before their lunch eating times. Scheduling this way would result in a greater amount of food eaten, less food waste, and possibly significantly less behavioral and health problems.
The most significant drawback is the logistics of having student gather their lunches and cleaning their hands before eating. However, these are clearly surmountable obstacles and may actually lead to the installation of more wash basins near the lunch areas to encourage students to wash their hands more often, especially before eating. Sometimes having to walk to bathrooms which may be some significant distance away and which may have a reputation for being messy and smelly would be enough of a discouragement for hand washing to make kids decide against it.