Validation of the Danish 7-day pre-coded food diary among adults: energy intake v. energy expenditure and recording length

Br J Nutr. 2009 Dec;102(12):1838-46. doi: 10.1017/S0007114509991292.


Under-reporting of energy intake (EI) is a well-known problem when measuring dietary intake in free-living populations. The present study aimed at quantifying misreporting by comparing EI estimated from the Danish pre-coded food diary against energy expenditure (EE) measured with a validated position-and-motion instrument (ActiReg). Further, the influence of recording length on EI:BMR, percentage consumers, the number of meal occasions and recorded food items per meal was examined. A total of 138 Danish volunteers aged 20-59 years wore the ActiReg and recorded their food intake for 7 consecutive days. Data for 2504 participants from the National Dietary Survey 2000-2 were used for comparison of characteristics and recording length. The results showed that EI was underestimated by 12 % on average compared with EE measured by ActiReg (PreMed AS, Oslo, Norway). The 95 % limits of agreement for EI and EE were - 6.29 and 3.09 MJ/d. Of the participants, 73 % were classified as acceptable reporters, 26 % as under-reporters and 1 % as over-reporters. EI:BMR was significantly lower on 1-3 consecutive recording days compared with 4-7 recording days (P < 0.03). Percentage consumers of selected food items increased with number of recording days. When recording length was 7 d, the number of reported food items per meal differed between acceptable reporters and under-reporters. EI:BMR was the same on 4 and 7 consecutive recording days. This was, however, a result of under-reporting in the beginning and the end of the 7 d reporting. Together, the results indicate that EI was underestimated at group level and that a 7 d recording is preferable to a 4 d recording period.

Publication types

  • Validation Study

MeSH terms

  • Adult
  • Anthropometry
  • Basal Metabolism
  • Denmark
  • Diet Records*
  • Diet Surveys
  • Energy Intake*
  • Energy Metabolism*
  • Exercise
  • Feeding Behavior
  • Female
  • Food
  • Humans
  • Male
  • Middle Aged
  • Surveys and Questionnaires
  • Time Factors