Some schools have banned junk food. Some have added longer gym classes, new nutrition classes, or even required standing desks. But childhood obesity rates are still about three times higher than they were in 1980. Now schools are adding another tool to the fight for fitter kids: Architecture. "We all know statistics about the childhood obesity epidemic, and we all know that despite our best efforts working very intensely at the individual level—or even at the population level—we haven't made as much of an inroad as we really want to," says Matt Trowbridge, an associa...