Having just finished Michael Pollan's book:  The Omnivore's Dilemma - I must say - buy or rent/borrow this book today! It is at your library or on the "Thought Provoking" table at Barnes and Noble!
Humans are omnivores - that is we are animals that will feed on any or many different kinds of food, including both plants and animals. Pollan follows each of the food chains that sustain us - industrial food, organic or alternative food and the food we forage ourselves (not that many of us do - but for the fisherman, hunters, gatherers out there...we still carry that in our DNA!) - to a final meal. His thoughtful narrative addresses the Iowa cornfields (6 billion taxpayer dollars subsidize the corn growing industry. We have too much corn - industry is trying to find new ways to use it all up - by using ethanol in the gas we use to drive our machines (even if it is not environmentally sound), as preservatives, and random products that you unknowingly consume or apply to your body (out of tthe 45,000 items in the average supermarket - 25% of them now contain corn. this includes toothpaste, cosmetics, disposable diapers, trash bags, cleansers, charcoal briquettes, matches, batteries) When you read about the amount of fossil fuels/petroleum it takes to fertilize and then grow/harvest/transport the corn - it is mindblowing.
Also - he takes you through food-science laboratories, feedlots or CAFOs (the ghetto/holocaust confinement centers for cattle), fast food restaurants, organic farms and huntinggrounds.
    The answers Pollan offers have profound impact on our environment, our health, or politics and it behooves everyone to educate themselves - you will have new appreciation for your food and a heightened awareness of your power as a consumer to make an impact on our environment and our food industry system with your choices.
MUST READ!!!!!!