Our findings highlight a stark economic dimension to observed imbalances in diet. Based on the diets reported by a representative sample of King County, Washington, residents, our analyses indicate that people attempting to bring their diet closer to recommended consumption levels for the nutrients we studied would probably have to pay higher food costs.The nutrients themselves are not expensive. In a 2009 study of diet models using the framework of USDA's Thrifty Food Plan, Joseph Llobrera and I explored different types of economic and nutritional constraints that one could try to meet. While choosing diets that are as similar as possible to current consumption patterns, it is fairly inexpensive to meet just nutrient constraints (like getting enough calcium and sufficiently low saturated fat). It is a bit more expensive to meet Pyramid food group constraints (like getting enough fruit). And it is more expensive still to meet idiosyncratic food-specific constraints (like getting enough of particular red meats).
The Health Affairs article is getting nationwide coverage today from the Associated Press, under the headline: "Healthy Eating is Privilege of the Rich, Study Finds." I am quoted for opposition to the main thesis. Journalists do this in part because of the intrinsic value of multiple points of view, and also for narrative tension, quoting one scholar against another. It is more fruitful to see this as an ongoing conversation in a community of researchers, trying to identify the economic and non-economic sources of unhealthy eating patterns, and reading each other's work with great interest and appreciation.
Addendum: Still mulling over this discussion, a good way to think quantitatively about these questions is to fiddle with our Thrifty Food Plan Calculator, on the Friedman School website. For example, the tab titled "good sources of..." has a list of the food groups that provide the most potassium per dollar, the most fiber per dollar, and the least saturated fat per dollar. These are the nutrients that featured most prominently in the Health Affairs article. Enjoy exploring.