Characterizing energy intake misreporting and its effects on intake estimations, in the Portuguese adult population.

OBJECTIVE: The aim of the current study was to evaluate energy intake misreporting prevalence, its associated factors and its effects on nutrient intake, in the Portuguese population aged from 18 to 84 years. DESIGN: Cross-sectional study. SETTING: Portugal. SUBJECTS: Adults participants from the National Food, Nutrition and Physical Activity Survey, IAN-AF, 2015-2016, who provided two complete 24 h dietary recall and complete covariate information. RESULTS: Under, plausible and over-reporters were identified according to the Goldberg method. Total misreporting prevalence was 29·9 %, being 28·5 % of under-reporting and 1·4 % of over-reporting. The current study found higher odds of being classified as an under-reporter especially in participants with higher BMI and in those who self-reported health perception status as non-favourable. Energy intake estimation increases by 853.5 kJ/d (204 kcal/d) when misreporters are excluded, and the same tendency is observed for macro and micronutrients. It is worth mentioning that the prevalence of inadequacy for protein intake decreases by about 5 % when considering plausible reporters. CONCLUSIONS: The exclusion of misreporters has a small impact on the crude energy and nutrient estimates as well as on assessing the contribution of nutrients to total energy intake. However, a moderate impact was observed in the estimation of nutrient inadequacy prevalence.