Diet quality in the United States is improving over time but remains poor. Food outlets influence diet quality and represent the environments in which individuals make choices about food purchases and intake. The objective of this study was to use the Healthy Eating Index-2015 (HEI-2015) to evaluate the quality of foods consumed from the four major outlets where food is obtained-stores, full-service restaurants, quick-services restaurants, and schools-and to assess changes over time. This cross-sectional study used 24 h dietary recall data from eight cycles (2003-2004 to 2017-2018) of the National Health and Nutrition Examination Survey (NHANES). Linear trend estimation was used to test for changes in HEI scores over time, and balanced repeated replicate weighted linear regression was used to test for differences in total and component scores between types of food outlets. Overall, Americans are not consuming a mix of foods from any major category of food outlet that aligns with dietary guidelines. The total score for schools (65/100 points) and stores (62/100 points) was significantly higher than full-service (51/100 points) and quick-service (39/100 points) restaurants (p < 0.0001). HEI scores significantly improved over time for schools (p < 0.001), including an increase in whole grains from less than 1 point in 2003-2004 to 7 out of 10 points in 2017-2018. In 2017-2018, schools received the maximum score for total fruits, whole fruits, and dairy. Continued research on strategies for improving the quality of foods consumed from restaurants and stores is warranted.
Keywords: HEI-2015; National Health and Nutrition Examination Survey (NHANES); What We Eat in America; dietary patterns; food environment; nutrition policy.