Could it be that what we don’t eat is destroying our environment? Historian Tristram Stuart argues that the vast amount of food that is wasted by manufacturers, supermarkets, farmers, and consumers — up to 50 percent of food grown in this country — has massive ecological consequences, leading to the depletion of the oceans, the decimation of rainforests to grow grains for livestock, and mountains of methane-emitting landfills. (Encore presentation.)