Diet Quality Usually Varies by Income Status
A recent ERS study of Americans' diets found that low-income groups tended to have lower quality diets than high-income groups. Not only does a higher income expand food choices, it is also related to factors that tend to improve diet quality, including higher education, better access to well-stocked grocery stores, and greater diet and health knowledge. This result, however, did not hold for children—diet quality among U.S. children did not vary by income.
The ERS study is based on the Healthy Eating Index (HEI), as computed by USDA’s Center for Nutrition Policy and Promotion using consumption data from the 1988-94 National Health and Nutrition Examination Survey. The HEI, scored from 0 to 100, measures an individual’s quality of diet based on 10 components, with higher scores closely conforming to recommendations of the Food Guide Pyramid prior to its 2005 revision.
Twelve percent of Americans age 2 and older had 'good' diets (an HEI score above 80), while the rest had diets that were poor in quality or needed improvement. Only 8 percent of people with very low household income (below 131 percent of poverty level) had good diets. Limiting fat and sodium intake and consuming the recommended servings of fruits and vegetables were particularly difficult dietary tasks for the lowest income Americans.
The diet quality of Americans age 60 and older varied the most by income status. Although older Americans' dietary quality was higher on average than that of the general population, their diet quality suffered the most as income fell. Nineteen percent of older Americans with very low household income had poor diet quality (an HEI score below 51), compared with 13 percent of low-income (between 131 and 185 percent of poverty level) older adults, and 9 percent of those with incomes above 185 percent poverty level.
The proportion of children who had poor diets did not vary by income. Overall, 16 percent of school-age children (ages 5-17) had poor diets. A number of factors could contribute to this finding. First, child nutrition programs, such as WIC, free or reduced-price school lunches, and subsidized meals in day care, could reduce variation in diet quality by income. Second, parents and other child-care providers may pay more attention to the dietary recommendations for children under their care than for themselves, and it may be easier to enforce good eating habits for one's children than to adhere to them oneself. Evidence suggests that as children age and make more of their own food choices, they, too, may find it harder to keep good eating habits—only 8 percent of children ages 2-4 had poor diets, versus 16 percent of school-age children.
Nutrition and Health Characteristics of Low-Income Populations: Healthy Eating Index, by Biing-Hwan Lin, USDA, Economic Research Service, February 2005