Report — From the February 2016 issue

The Trouble with Iowa

Corn, corruption, and the presidential caucuses

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Virtually all of the corn that doesn’t go to ethanol is eventually consumed by humans, but it usually gets to our plates by a circuitous route. One way or another it is processed. About 12 percent is funneled into industrial refineries that crack corn into its elements: starches and sugars — especially in the form of high-fructose corn syrup, the basis of the high-energy diet that makes so many people sick and fat.

It ought to be harder than it is to account for the American diet. There are, after all, thousands of edible domesticated plants, dozens of animals, and endless ways to raise, combine, and create food. The big picture, however, is depressingly easy to paint. American agriculture is corn, soybeans, wheat, and hay — four crops that account for 85 percent of the nation’s farmable land. In Iowa, corn and soybeans cover 23 million of the state’s 24 million acres of cropland. One presidential candidate has a literally visceral understanding of the health implications of this fact. Jeb Bush slimmed down substantially before hitting the campaign trail by adopting the popular paleo diet, which can perhaps best be defined as avoiding any of the food that Iowa produces. Yet he doesn’t talk about his personal and quite correct understanding of the country’s fundamental nutrition problem. Instead he ate a deep-fried Snickers bar at the Iowa State Fair, a ritual display of self-flagellation that has become necessary in a state where about a third of the people are obese.

A TV reporter at the Harkin Steak Fry, an annual fund-raiser hosted by Iowa Senator Tom Harkin, in Indianola, Iowa, 2014

A TV reporter at the Harkin Steak Fry, an annual fund-raiser hosted by Iowa Senator Tom Harkin, in Indianola, Iowa, 2014

The national obesity numbers are not much different, and there has been much bickering among nutritionists, an endless series of conflicting results from gold-standard randomized controlled trials, about the roots of the epidemic, which is responsible for as much as one in four dollars spent on health care in the United States. But there is a simple way to approach the question: we can account for the flow of food. Per capita U.S. consumption of protein and fats has not changed much over the past half-century. Per capita consumption of carbohydrates, however — sugars and starches and Snickers bars made from corn syrup — has risen consistently.

Meanwhile, though fat consumption has not changed in the past fifty years, the composition of the fats in our diet has changed drastically. When researchers tracked the American diet from 1909 to 1999, one commodity stood out. Per capita consumption of soybean oil increased a thousandfold. No other food came close to matching that number.

Soybeans are corn’s fellow travelers, grown by farmers not because there is great demand for veggie burgers, edamame, and tofu but because they complement corn in crop rotation. Most soybeans go to processed food and livestock. The component of soybean oil that is at issue in the obesity epidemic is linoleic acid, a fat that is common to many vegetable oils and ubiquitous in processed foods. Before the middle of the twentieth century, Americans got about 1 percent of their energy from linoleic acid; now they get about 8 percent. When researchers replicated that change in a diet fed to lab animals, with no increase in total calories, the animals became obese. When the linoleic acid was reduced, the obese mice became skinny. The scientists then bred four generations of mice and found that a fixed diet with a high proportion of linoleic acid produced more obesity in later generations. Linoleic acid belongs to a class of fats, the omega-6s, that have supplanted the other important group of fats, omega-3s, largely animal fats, in our diets. There is even some evidence that linoleic acid prevents our bodies from using what omega-3s we do receive from our food. Omega-3s are crucial for brain development. It is probably too cynical to suggest that food marketers planned a diet that compromised our intelligence, but at least they created a situation they can work with.

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’s “Bakken Business” appeared in the March 2013 issue of Harper’s Magazine.This article was produced in collaboration with the Food & Environment Reporting Network.

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