Using data from the National Health and Nutrition Examination Survey (NHANES) 2003-2012, we investigated the prevalence and characteristics of under-reporting and over-reporting of energy intake (EI) among 19 693 US adults ≥20 years of age. For the assessment of EI, two 24-h dietary recalls were conducted using the US Department of Agriculture Automated Multiple-Pass Method. Under-reporters, acceptable reporters and over-reporters of EI were identified by two methods based on the 95 % confidence limits: (1) for agreement between the ratio of EI to BMR and a physical activity level for sedentary lifestyle (1·55) and (2) of the expected ratio of EI to estimated energy requirement (EER) of 1·0. BMR was calculated using Schofield's equations. EER was calculated using equations from the US Dietary Reference Intakes, assuming 'low active' level of physical activity. The risk of being an under-reporter or over-reporter compared with an acceptable reporter was analysed using multiple logistic regression. Percentages of under-reporters, acceptable reporters and over-reporters were 25·1, 73·5 and 1·4 %, respectively, based on EI:BMR, and 25·7, 71·8 and 2·5 %, respectively, based on EI:EER. Under-reporting was associated with female sex, older age, non-Hispanic blacks (compared with non-Hispanic whites), lower education, lower family poverty income ratio and overweight and obesity. Over-reporting was associated with male sex, younger age, lower family poverty income ratio, current smoking (compared with never smoking) and underweight. Similar findings were obtained when analysing only the first 24-h recall data from NHANES 1999-2012 (n 28 794). In conclusion, we found that misreporting of EI, particularly under-reporting, remains prevalent and differential in US adults.
