There are, most of us agree, excellent reasons for committing to a meatless diet. For one thing, our passion for meat has a negative impact on the environment. Of the 40 percent of the earth’s surface used for agriculture, a whopping third is used just to grow animal (not people) food. In the United States, studies show, raising livestock accounts for 55 percent of land erosion, 37 percent of pesticide use, and 50 percent of antibiotic consumption. Globally, livestock are responsible for about 18 percent of greenhouse gas emissions—flatulent cows are doing the atmosphere no good—and food animals, collectively, slurp up about a third of the world’s fresh water.

Since many food animals are raised in wretched conditions on factory