Most of us are aware that our food choices have environmental consequences. (Who hasn’t heard about the methane back draft from cows?) But when it comes to the specifics of why our decisions matter, we’re at a loss, bombarded with confusing choices in the grocery-store aisles about what to buy if we care about planetary health. Are organic fruits and vegetables really worth the higher prices, and are they better for the environment? If I’m a meat eater, should I opt for free-range, grass-fed beef? Is it OK to buy a pineapple flown in from Costa Rica, or should I eat only locally grown apples?