Trays started disappearing from university cafeterias several years ago. Not for the usual reason, to be used as sleds in winter, or for the best reason, for college-age secret agents to slip under their jackets as impromptu torso protection against enemy shivs or poisoned blow darts.
Trays have been on their way out just because they hold too much food. If you're walking through a cafeteria line, all that real estate is a cue to take more food than you might want to eat.
This came up on World Food Day last week, at an event I moderated at Bloomberg headquarters with Craig Hanson, director of the People & Ecosystems Program at the World Resources Institute, and Marcus Samuelsson, the celebrated chef whose current restaurants include the Red Rooster Harlem.
Hanson is overseeing a series of WRI reports about the projected world food shortage. His team's research suggests that the agricultural sector will have to produce 60 percent more kilocalories in 2050 than in 2006, to feed more than 9 billion people.