In nationally representative surveys conducted between 1999 and 2012, several improvements in self-reported dietary habits were identified, such as increased consumption of whole grains, with additional findings suggesting persistent or worsening disparities based on race/ethnicity and education and income level, according to a study appearing in the June 21 issue of JAMA.

Suboptimal diet is among the leading causes of poor health, particularly obesity, diabetes, cardiovascular diseases, and diet-related cancers. In the United States, dietary factors are estimated to account for more than 650,000 deaths per year and 14 percent of all disability-adjusted life-years lost. Understanding trends in dietary habits is crucial to inform priorities and policies to improve diets and reduce diet-related illness. Dariush Mozaffarian, M.D., Dr.P.H., of the Tufts Friedman School of Nutrition Science and Policy, Boston, and colleagues examined trends in overall diet quality and multiple dietary components related to major diseases using 24-hour dietary recalls in nationally representative samples that included 33,932 U.S. adults age 20 years or older from 7 National Health and Nutrition Examination Survey (NHANES) cycles (1999-2012). As a summary indicator, a diet score was constructed based on the American Heart Association (AHA) 2020 Strategic Impact Goals for diet.

The researchers found that many aspects of the U.S. diet improved, including increased consumption of whole grains, nuts or seeds, a slight increase in fish and shellfish and decreased consumption of sugar-sweetened beverages. Other dietary trends included increased consumption of whole fruit and decreased consumption of 100 percent fruit juice. No significant trend was observed for other diet score components, including total fruits and vegetables, processed meat, saturated fat, or sodium. The estimated percentage of U.S. adults with poor diets declined from 56 percent to 46 percent. The percentage with ideal diets increased but remained low (0.7 percent to 1.5 percent).

Disparities in diet quality were observed by race/ethnicity, education, and income level; for example, the estimated percentage of non-Hispanic white adults with a poor diet significantly declined (54 percent to 43 percent), whereas similar improvements were not observed for non-Hispanic black or Mexican American adults. There was little evidence of reductions in these disparities and some evidence of worsening by income level.

"These findings may inform discussions on emerging successes, areas for greater attention, and corresponding opportunities to improve the diets of individuals living in the United States," the authors write.

Editorial: Changing Dietary Habits and Improving the Healthiness of Diets in the United States

Margo A. Denke, M.D., formerly with the University of Texas Southwestern Medical Center, Dallas, comments on the findings of this study in an accompanying editorial.

"Achieving dietary changes remains a challenging task. The advice of clinicians may not provide lasting effects unless patients can incorporate meaningful dietary changes into a daily sustainable pattern. How to best accomplish this task is the goal. The article by Rehm et al provides a current dietary report card to help with this task. Even though there has been some improvement from 1999 to 2012, clinicians, patients, and the food industry all need to work together to meet the challenge of improving the healthiness of the U.S. diet."