A few years ago, an obesity researcher at the University of Washington named Adam Drewnowski ventured into the supermarket to solve a mystery.

Drewnowski found that a dollar could buy 1,200 calories of cookies or potato chips but only 250 calories of carrots. Looking for something to wash down those chips, he discovered that his dollar bought 875 calories of soda but only 170 calories of orange juice.

He discovered that he could buy the most calories per dollar in the middle aisles of the supermarket, among the towering canyons of processed food and soft drink. (In the typical American supermarket, the fresh foods - dairy, meat, fish and produce - line the perimeter walls, while the imperishable packaged goods dominate the center.) Drewnowski concluded that the rules of the food game in America are organized in such a way that if you are eating on a budget, the most rational economic strategy is to eat badly - and get fat.

To learn more about how the 2007 Farm Bill is aiding and abetting this strategy, buy the July/August edition of Touch the Soil magazine at a retail outlet or subscribe online.