Whatever their rationale, most people do prefer fresh produce over canned and frozen. Whether that's a function of taste or culture—or some combination of the two—the allure of freshness affects everyone from food writers to welfare moms. A 2007 survey in Maryland found that parents enrolled in the WIC program avoid fruits and vegetables with a "canned taste" [PDF]. Many impoverished women also say that fresh products are healthier and worry that metal packages will poison their children. (This latter concern makes sense: Many of the plastic linings used in canned foods are made from Bisphenol A, a chemical that may be dangerous to infants. Producers are searching hard for an alternative.)
If we grant that canned and frozen vegetables taste bland, we can't deny that they're cheaper than what you'd get in the produce aisle. A USDA report from 2004 found similar prices per serving among the various produce options, but that was strictly in terms of price paid at the cash register. If you account for auxiliary costs, there's no comparison. Canned and frozen products are significantly easier to use, as there's no need to wash, cut or trim. They also last longer in the pantry, which means less spoilage and wasted food. (Americans toss out about 100 billion pounds of food every year. According to a government study, fresh fruits and vegetables are among the items most often thrown away—a fact that makes them less eco-friendly than processed foods.)
So what happens if you don't have much money for food? The easiest way to maximize taste, cost, and convenience—the three most important elements of food choice—is to skip fruits and vegetables altogether. Dietary bogeymen like refined grains, added sugars, and added fats happen to be both cheap and delicious.
This cost differential may be the most important reason why rich people eat more fruits and vegetables than poor people. The disparities in consumption have grown in recent years, especially when it comes to fresh produce. In fact, the correlation between your social class and what you buy at the supermarket is strong enough to cloud our most basic understanding of public health. We say that fruit and vegetable intake is associated with good health but the big, observational studies upon which we base that claim are plagued with confounding variables: People who eat produce are healthier and are not as obese, but they also have more money, smoke less, exercise more, and have better health coverage. It's hard to know which, if any, of these qualities makes the difference.
Let's not get blinded by uncertainty: Just about every nutritionist agrees that fruits and vegetables are wholesome on their own terms, even if we don't have a mountain of direct evidence. But social and cultural factors seem likely to play a role in the benefits of fresh produce. We know, for example, that people have lower rates of chronic disease when they live in neighborhoods with supermarket produce aisles. That could mean that poor people get sick because they don't have access to fresh fruits and vegetables. Or, it could mean that rich people, who are already healthy, happen to be eating fresh produce. We might ask the same question of any other high-end foodstuff that turns up more often in posh ZIP codes—blue cheese, perhaps, or $200-per-pound Jamon Iberico de bellota.
What does all this mean for our fruit-and-vegetable policy? By insisting that food from the farmer's market tastes better and improves your health, our fruit-and-vegetable policies mix up science and culture. Under the guise of evidence-based public health, they export a set of values from one social class to another. They're reinforcing the idea that fresh is the only kind of produce worth eating—even though it's more expensive and less accessible than canned and frozen. In that sense, fresh subsidies may be self-defeating: They improve access to one kind of health food while stigmatizing the sensible alternatives. What will happen if children learn to thumb their noses at frozen corn and canned beans? Will that shrink the fruit-and-vegetable gap, or will it only make things worse?
Correction, March 30, 2010: This article originally stated that the paper was from UC-Irvine. (Return to the corrected sentence.)