Abbreviations:
SECONDARY, CHRONIC DISEASES
In many European countries, national dietary surveys are conducted to monitor populations’ dietary intake and physical activity levels (PAL). Accurate and reliable dietary data are crucial for food safety, public health initiatives and sustainability. The results from the Danish National Survey of Diet and Physical activity (DANSDA) are used to investigate associations and generate new hypotheses between dietary exposures (nutrients, foods/food groups, dietary patterns, eating behaviour) or physical activity (PA) and risk factors for chronic diseases and nutrient status. Furthermore, results are used to evaluate nutrition and public health policies (compliance with food-based dietary guidelines, nutrient recommendations and PA guidelines), sustainability of diets and exposure assessment of natural toxicants, contaminants, additives and other food chemicals for risk assessment.To obtain consistent and comparable food and nutrient data across countries and to facilitate uniform legislation on food safety, the European Food Safety Authority (EFSA) has suggested that the 2 × 24 h diet recall (2 × 24 h DR) assessment method should be implemented in EU countriesIn Denmark, a 7-d self-administered food diary (7 d FD) has been applied since 1995, and PA measurements (questionnaire and/or pedometry and a 7-d step diary) have been included since 2000 in the DANSDAThe DANSDA method includes a food diary, which participants fill in for seven consecutive days. The 7 d FD has been developed into a web-based food diary that contains a comprehensive food list, where all portion sizes are estimated by a series of photos of commonly eaten food items. The web-based food diary has been validated in 8–11-year-old children for EI against TEE (estimated by accelerometers)The suggested 2 × 24 h DR is a retrospective assessment method, which may minimise the risk of changes in dietary behaviour caused by registration itself. However, the 2 × 24 h DR is known to be prone to socially desirable answers (if interviewer-administered) and depend on the participant’s memoryThe primary objective of the present study was to use TEE measured by the DLW technique as a biomarker to validate EI estimated by both the self-administered web-based 7 d FD and the interviewer administered 2 × 24 h DR methods and to assess participant acceptability of the two diet registration methods. Furthermore, secondary objectives were to examine if adding a third recall provides an additional improvement in EI estimates and evaluate pedometer-determined steps and self-reported moderate-to-vigorous PA (MVPA) during leisure as predictors of PA energy expenditure (PAEE).