When the federal government subsidizes a crop, farmers are enticed to grow more of it, which drives supply up and prices down. Food manufacturers buy more abundant cheap crops and thus more of them stream into the food supply. If the food happens to be unhealthy, that's a problem. Or so the argument goes.
Corn, which reaps nearly 40 percent of the subsidies, and wheat are the most heavily subsidized. They are also staples in a variety of common, fattening, nutrition-deficient foods.
Corn is the main ingredient in high-fructose corn syrup, a cheap sweetener laced into packaged foods and sodas. Wheat gets refined into flour, a chief component of breads, bagels, processed cereals, cakes, cookies and muffins — foods nutritionists refer to as simple or "bad" carbohydrates. Both corn and wheat are heavily used to feed livestock, a leading source of saturated fats.
Subsidies also encourage farmers to focus on innovations that aid the production of those crops, making them even cheaper.
So has the government tipped the food scale in a direction that makes us fat?
Not so fast, say agricultural economists.
"I get annoyed because everyone points to farm subsidies as one of the top two reasons for the obesity epidemic, but it's irrelevant," said Julian Alston, professor of agricultural economics at the University of California, Davis, adding that eliminating farm subsidies would have a negligible effect on obesity rates.
"If farm subsidies have contributed to America's obesity epidemic, the impact has been slight and indirect," added Richard Post, director of the Center for Nutrition Policy for the USDA, creator of the new My Plate nutrition guidelines. "Subsidies have a far smaller impact on shelf price than many Americans think."
Not all about the money
However, the Environment Working Group — a nonprofit public-health advocacy group that has been tracking and condemning farm-subsidy policy for years — sees the matter differently.
"Decades of subsidizing big grain growers have assured a cheap, steady supply of corn and wheat, which is in almost every food on the shelves," said David Degennaro, legislative analyst for the environmental group. "It has contributed indirectly to making the wrong kind of calories cheaper."
Even so, said Post, "If the price of corn went up 50 percent, the net effect would increase the cost of a box of cornflakes by 1.6 cents or a 2-liter bottle of soda by 1.9 cents. That is not likely to impact consumer behavior."
Another report shows that a 30 percent increase in the price of feed grain would raise the price of meat and poultry by 4 to 5 percent.
Such a shift could affect consumer behavior, said Lisa Powell, a senior research scientist at the Institute for Health Research and Policy at the University of Chicago. "Individuals are sensitive to food pricing."
Powell has done studies that show the consumption of fresh fruits and vegetables goes up when prices go down. She's also found that food price and weight are related.
In a study she published in 2009, children's weight was sensitive to the price of fruits and vegetable, and that was particularly true for low-income children. "A 10 percent reduction in fruit and vegetable prices reduced low-income children's BMI by 1.4 percent," Powell said.
But shelf price isn't the only issue here. There's also the problem of conflicting agendas.