The first time I bought celery in a Manila grocery store, I was surprised to find the stalks still crowned with leaves. Accustomed to the neatly trimmed, plastic-bagged bunches in American supermarkets, I was mildly peeved over the extra effort I had to make to cut off the tops, even if it involved nothing more than a solid thwack of a chef’s knife to decapitate those unwanted greens. I swept them from the cutting board into the trash without another thought, blithely unaware that I had just added to the more than 200 pounds per person of edible food discarded around the world last year.