Pollan's main thesis in this book is that we in the United States need to adopt a lifestyle in which we get our food from the "pastoral" food chain rather than from the industrial one.
Pollan argues that we get the vast majority of our food (even the food that is sold as "organic") from an industrial food chain. He says that this food chain is bad for the environment, bad for the animals that are raised in it, and bad for the quality of the food that it produces. Instead, he says, we should rely on the pastoral food chain. He believes that we should be eating food that is grown locally and in a more old-fashioned and sustainable way. This food would taste better and the way that it is raised would be better for the environment and for the animals that we eat as well.