The elephant inside our food system and even beyond is corn. Its presence is pervasive and dominant. It is an integral part of industrialized agriculture and the industrialized food chain. Processed food relies heavily on corn. Take a look at any wrapper or can and see for yourself. Cows fatten up on corn. It contributes to obesity in humans. And growing it? Not so good. It consumes prodigious amounts of fossil fuel energy. And corn turns out to be a major reason why farmers in Mexico go broke and migrate to the U.S. Under NAFTA, American taxpayer subsidized corn is dumped in Mexico at below market prices. Mexican farmers can't compete. More than two million of them have been thrown off the land

Michael Pollan, professor of journalism at the University of California at Berkeley, is a contributing writer to the New York Times Magazine. He is the author of The Botany of Desire. His The Omnivore's Dilemma was selected as one of the ten best books of 2006 by the New York Times.