Michael Pollan pretty famously wrote The Omnivore's Dilemma; A Natural History of Four Meals. If you haven't read it, you probably should. Unless you're really hung up on your current eating patterns. One of Pollan's points, of course, is that the way North Americans eat takes no account whatever of the lifespan greenhouse gas emissions created by the food we choose to eat. It's a legitimate point, and a significant one, and my family has changed -- to an extent -- the way we eat, as a result.