Two-thirds of our calories now come from just four crops: rice, soy, wheat and corn

Nicholas Kristof - Food for the Soul - NYTimes.com:

"Michael Pollan, the food writer, notes that monocultures in the field result in monocultures in our diets. Two-thirds of our calories, he says, now come from just four crops: rice, soy, wheat and corn. Fast-food culture and obesity are linked, he argues, to the transformation from family farms to industrial farming."