The magazine of the UW School of Public Health

View Point

The High Price of Low-Cost Foods

A guest editorial by Adam Drewnowski and Pablo Monsivais

Food Checkout Day was February 6 this year. Sponsored by farm bureaus around the US, it celebrates the day—counted from January 1—when the average American household had earned enough disposable income to pay for a year’s worth of food. The early February date draws attention to the fact that only 37 days of work are needed to provide a household with food for a whole year. By all accounts, Americans enjoy the most affordable food supply in the world, spending less than 10 percent of their disposable income on food.

The apparent affordability of the American diet hides a darker truth: Not all foods have become more affordable. Calories have become cheap in our food supply, but nutrients—the vitamins, minerals and other dietary components that we need for health—still carry a price premium. Fresh produce, seafood, and lean cuts of meat are good sources of nutrients, but are expensive sources of calories. In contrast, refined grains, sugars, and fats provide calories at a very low cost, but those calories are often “empty,” or nutrient free.

Research has shown that obesity rates in the US, including the Pacific Northwest, are higher among groups with lower education and income levels. Higher rates are observed in lower-income states, in poor counties and legislative districts, and in disadvantaged zip code areas and neighborhoods. One theory holds that inequities in access to healthy foods are responsible for the social gradient in obesity rates. Energy-dense (high-calorie) sugars and fats are inexpensive, readily available, and satisfying. In contrast, many healthier foods have become luxury items, well beyond the reach of the low-income consumer. Diet quality, in fact, is a reliable index of social class.

Food prices and energy
density are inversely linked, as this graph of 339 foods shows. Although average food prices have declined relative to incomes, a large and growing affordability gap exists between the more healthful and less healthful foods, and that price gap by nutrient quality appears to be growing over time. US Department of Agriculture statistics show that real prices for fresh fruits and vegetables rose more than 140 percent between 1984 and 2002; prices for sugars and sweets fell by 12 percent, and soft drinks fell by 30 percent over the same period.

A study conducted in Seattle supermarkets in 2004, and again in 2006, showed that the most healthful foods of lowest energy density increased in price by almost 20 percent over a two-year period, outpacing inflation. By contrast, the price of energy-dense foods remained constant.
Several studies have now shown that poor diet quality, rather than total energy consumed, is a predictor of higher obesity rates. One possibility is that low diet costs, rather then the consumption of any particular food or beverage, are the best predictor of weight gain. For example, it is easier to overeat inexpensive and energy-dense potato chips than a spinach salad.

Is it possible to achieve a nutritious diet at low cost? In theory, yes. The USDA’s Thrifty Food Plan (TFP) is essentially a shopping list and menu planner that uses complex statistical algorithms to optimize the recommended foods and menus. The TFP achieves its goal by balancing the cost and nutrition of foods across food groups. However, the TFP does not take into consideration that dietary choices are also driven by limited time and social and cultural norms.

Obesity in America is largely an economic issue. Many past approaches to preventing or controlling obesity have been based on information, education, and theories of behavior change. The emphasis has been on decisions or choices made by the obese person. But the realization is emerging that some economic choices are beyond individual control. As a result, the obesity epidemic must be approached from the environmental and policy standpoint. A convergence between agricultural policy and public health is long overdue. A coherent agricultural policy, in the Pacific Northwest and beyond, is needed to stop Americans from becoming some of the most overfed, yet undernourished, people on Earth.

Adam Drewnowski, PhD, is director of the Nutritional Science Program and Pablo Monsivais, PhD, MPH, is a research analyst with the Center for Public Health Nutrition at the UW School of Public Health and Community Medicine.

Table caption: Food prices and energy density are inversely linked, as this graph of 339 foods shows. (Prices collected in 2006 from Safeway, Albertsons, and QFC in Seattle. Adapted from Monsivais and Drewnowski, Journal of the American Dietetic Association, 2007;107(12):2071-6.)

Print version of this editorial (pdf)