The Omnivore's Dilemma is the question posed at the beginning of Michael Pollan's book, “What should we have for dinner?” Pollan goes on to explain that this question is much more complicated than it appears. He not only tries to answer the question, but also to explain why it is so complex and has vast ramifications for the world.
An omnivore, by definition, can eat "just about anything nature has to offer." In this situation, it is only to be expected that we start to worry about what we should eat.