Fast Food Made Up Mostly of Corn

John Roach
for National Geographic News
November 11, 2008
If you are what you eat, most Americans are an ear of corn, new research suggests.

A chemical analysis of popular fast foods reveals that some form of the grain appears as a main ingredient in most items—especially beef.

The researchers examined the molecular makeup of hamburgers, chicken sandwiches, and french fries purchased from three fast food chains in six U.S. cities.

"Out of the hundreds of meals that we bought, there were only 12 servings of anything that did not go straight back to a corn source," said study lead author Hope Jahren, a geobiologist at the University of Hawaii in Honolulu.

Corn's dominance in the nation's fast food is well known, "but the [chemical analysis] really bring it home in a way that hasn't been brought home before," said Craig Cox, Midwest vice president for the nonprofit Environmental Working Group.

It All Goes Back to Corn

Corn, noted study author Jahren, has a unique biochemistry that allows researchers to identify its signature as it passes through the food chain—from plant to animal tissue to cooked human food, for example.
Jahren and colleagues used this signature to see if the contents of fast food matched how restaurants' said their foods are made and what ingredients they contain.

Such details from Wendy's, McDonalds, and Burger King were "vague and euphemistic," Jahren said.

The team's analysis, however, told a "very simple, straightforward story—it all went back to corn."

French fries are often cooked in corn oil, and cows and chickens eat either corn or feed fertilized with corn.

Not only was the signature of corn dominant, it was remarkably homogenous across the country in different restaurants, she added.

Subsidized System

Corn's U.S. prevalence is reinforced by a basket of federal subsidies that encourages farmers to specialize in corn production.

This has, in turn, encouraged the meat industry to base their productivity around corn, ratcheting up the overall demand for the grain.

"It is this self-reinforcing cycle that gets set up and supports this whole industrial model of meat production," said Cox of the working group.

The end result is a food system rife with corn, which carries a host of health consequences.

Early scientific literature on people eating corn-fed meat instead of grass-fed meat—a more natural food source—is revealing changing the composition of fats in the human diet.

(Related: "Cloned Pigs Produce Healthy Fat, Heart-Smart Pork?" [March 27, 2006].)

This shift may be at the root of human-health issues such as upticks in heart disease, diabetes, and obesity, author Michael Pollan noted in his 2006 book Omnivore's Dilemma.

(Get the facts on human diseases.)

Leaky Cornfields

From an environmental standpoint, the situation isn't much better.

Corn receives about 35 percent of all agricultural pesticides and 40 percent of all commercial fertilizer used in the U.S.

And since cornfields are "inherently leaky," a lot of these chemicals are lost to the water and air, noted Cox.

For instance, nitrogen—which comes from fertilizers—in the form of nitrous oxide is a greenhouse gas 300 times more potent than carbon dioxide.

Consumers ought to know what is in the meat they consume, lead author Jahren said.

"The really important thing we've done is highlighted this information gap."

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