Can United States adults accurately assess their diet quality?

Authors: Thomson, Jessica; LANDRY, ALICIA - University Of Central Arkansas; Walls, Tameka

Submitted to: American Journal of Health Promotion
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/7/2022
Publication Date: 11/2/2022
Citation: Thomson, J.L., Landry, A.S., Walls, T.I. 2022. Can United States adults accurately assess their diet quality? American Journal of Health Promotion. 37(4):499-506. https://doi.org/10.1177/08901171221137056.
DOI: https://doi.org/10.1177/08901171221137056

Interpretive Summary: The link between diet and disease is irrefutable yet diet quality remains low among United States (US) adults suggesting the need for concentrated efforts to move diets out of the “needs improvement” category. Using a single question to assess an individual’s diet quality may be a useful screening tool for dietary interventions. Thus, the objective of this study was to provide an estimate for the percentage of adults who can accurately assess the quality of their diet. Secondary objectives included exploring differences in sociodemographic characteristics, body weight and dietary plan awareness and use between adults who did and did not accurately assess the quality of their diet. Perceived diet quality was measured with the question “How healthy is your diet?” Measured diet quality was assessed using dietary recalls and the Healthy Eating Index, a tool that measures how well an individual’s diet aligns with the Dietary Guidelines for Americans. Accurate diet quality assessments were based on the following matches between perceived and measured diet quality (converted to a letter grade): excellent = A, very good = A or B, good = B or C, fair = C or D, and poor = D or F. Overall, only 15% of adults accurately assessed the quality of their diet, although accuracy exceeded 95% in the poor perception group. Additionally, 75% of adults overrated the healthfulness of their diet. Females, adults with low educational attainment, and those with low or very low food security were more likely to accurately assess the quality of their diet. In general, US adults cannot accurately assess the quality of their diet except for those perceiving their diet as poor. The tendency of US adults to overrate the quality of their diet suggests that work is needed to educate adults about what constitutes a healthful diet and how to apply this knowledge to accurately perceive their own diet.

Technical Abstract: Introduction: Our objective was to estimate the percentage of United States (US) adults who can accurately assess their diet quality. Methods: Using data from the National Health and Nutrition Examination Survey 2015-2018, we assessed measured diet quality using 24-hour dietary recalls scored using the 2015 Healthy Eating Index (HEI-2015). We categorized HEI-2015 scores using a 10-point grading scale. Perceived diet quality was measured by asking adults, aged =20 years, how healthy is your diet? Five responses included excellent, very good, good, fair, and poor. We classified the following matches between measured and perceived diet quality as accurate: A=excellent, A or B=very good, B or C=good, C or D=fair, and D or F=poor. We classified all others as inaccurate. Analyses included descriptive statistics and logistic regression for complex survey designs. Results: Based on 9,757 adults, <1%, 3%, 9%, 19%, and 70% scored diet quality grades of A, B, C, D, and F, respectively; 8%, 22%, 41%, 24%, and 6% perceived their diet quality as excellent, very good, good, fair, and poor, respectively. Overall, 15% of adults accurately assessed their diet quality with 96% accuracy in the poor perception group and less than 23% in the other four groups. Overall, 75% of adults overrated their diet’s healthfulness. Females, adults with lower educational attainment, and those with low food security were more likely to accurately assess their diet quality. Conclusion: US adults cannot accurately assess their diet quality except for those perceiving their quality as poor, and the majority overrate their diet quality.