Purpose: To estimate the percentage of United States adults who accurately assessed their diet quality (DQ).
Design: Observational, cross-sectional, nationally representative.
Setting: National Health and Nutrition Examination Survey, 2015-2018.
Sample: 9757 (86%) of 11 288 adults aged ≥20 years.
Measures: Perceived DQ was assessed by asking participants, how healthy is your diet? The five responses included excellent, very good, good, fair, and poor. Measured DQ was assessed using 24-hours dietary recalls scored with 2015 Healthy Eating Index; scores were categorized using a 10-point grading scale.
Analysis: Matches between perceived and measured DQ that were classified as accurate included: excellent = A, very good = A or B, good = B or C, fair = C or D, and poor = D or F. All others were classified as inaccurate. Analyses included descriptive statistics and multivariable logistic regression for complex survey designs.
Results: 63% of adults perceived their DQ as very good or good while 70% scored DQ grades of F. Overall, 15% of adults accurately assessed their DQ with 96% accuracy in the poor perception group and <23% in the other 4 groups. Overall, 75% of adults overrated their DQ. Females, adults with lower educational attainment, and those with low food security were more likely to accurately assess their DQ.
Conclusion: Adults cannot accurately assess their DQ except for those perceiving their DQ as poor, and the majority overrate their DQ.
Keywords: MyPlate; NHANES; United States; adult; diet; education; ethnicity; food security; healthy eating index; nutrition assessment; nutrition surveys; perceived diet quality; racial groups.