Who are the 'low energy reporters' in the dietary and nutritional survey of British adults?

Background. Underreporting in dietary surveys is a potential source of bias in studies of diet and disease, The aim of this study was to identify characteristics of men and women participants in the Dietary and Nutritional Survey of British Adults (DNSBA) who stated that they were neither slimming nor ill, and who reported an average energy intake over a 7-day period below 1.2 times estimated basal metabolic rate (BMR), termed here 'low energy reporters' (LER). Methods. In all, 2197 men and women aged 16-64 years participated in the DNSBA. Dietary intake was assessed using the 7-day weighed intake method. Their BMR was estimated using predictive equations based upon age, sex and body weight. Results. Compared with non-LER, LER had higher mean ratios of urinary urea nitrogen to dietary nitrogen and urinary potassium to dietary potassium, indicating that, as a group, LER were underreporting at least for protein and potassium intakes. Overall LER were overrepresented among the manual social classes, smokers, and self-reported non-alcohol drinkers, and were on average heavier than non-LER. There was indication of differential reporting of foods and differences in macronutrient and micronutrient densities between LER and non-LER. Conclusion. These results suggest that LER may be overrepresented within specific population subgroups and that underreporting bias may not be food and nutrient neutral. This has implications for the design and interpretation of studies of diet and disease.