We have learned not to take food seriously: we eat as much as we want of what we want when we want it, and we seldom think about the health and environmental consequences of our choices. But the fact is that every choice we make has an impact on our health and on the environment. In The Vegetarian Imperative, Anand M. Saxena, a scientist and a vegetarian for most of his life, explains why we need to make better choices: for better health, to eliminate world hunger, and, ultimately, to save the planet.

Our insatiable appetite for animal-based foods contributes directly to...