McDonald’s has a pretty unsavory reputation when it comes to public health. Lately the company has taken some steps to improve its image, launching vegetarian restaurants in India and putting fresh apples into Happy Meals. But there’s something at the core of its business that has at least the potential to do some good for both our waistlines and a different kind of waste: our waste of food. McDonald’s offers flexible portions.

Walk through those golden arches and you have your choice of a cheeseburger, double cheeseburger, quarter pounder with cheese, or double quarter pounder with cheese. Chicken nuggets? Do you want four, six, nine, or 20? Fries with that or no? It’s choice, and we Americans love choice. But it also means only ordering (and only spending money on) the food we actually intend to eat.