How accurate are adolescents in portion-size estimation using the computer tool Young Adolescents' Nutrition Assessment on Computer (YANA-C)?

Br J Nutr. 2010 Jun;103(12):1844-50. doi: 10.1017/S0007114510000127. Epub 2010 Feb 4.


Computer-administered questionnaires have received increased attention for large-scale population research on nutrition. In Belgium-Flanders, Young Adolescents' Nutrition Assessment on Computer (YANA-C) has been developed. In this tool, standardised photographs are available to assist in portion-size estimation. The purpose of the present study is to assess how accurate adolescents are in estimating portion sizes of food using YANA-C. A convenience sample, aged 11-17 years, estimated the amounts of ten commonly consumed foods (breakfast cereals, French fries, pasta, rice, apple sauce, carrots and peas, crisps, creamy velouté, red cabbage, and peas). Two procedures were followed: (1) short-term recall: adolescents (n 73) self-served their usual portions of the ten foods and estimated the amounts later the same day; (2) real-time perception: adolescents (n 128) estimated two sets (different portions) of pre-weighed portions displayed near the computer. Self-served portions were, on average, 8 % underestimated; significant underestimates were found for breakfast cereals, French fries, peas, and carrots and peas. Spearman's correlations between the self-served and estimated weights varied between 0.51 and 0.84, with an average of 0.72. The kappa statistics were moderate (>0.4) for all but one item. Pre-weighed portions were, on average, 15 % underestimated, with significant underestimates for fourteen of the twenty portions. Photographs of food items can serve as a good aid in ranking subjects; however, to assess the actual intake at a group level, underestimation must be considered.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Belgium
  • Child
  • Computers
  • Diet Records
  • Diet*
  • Female
  • Humans
  • Male
  • Mental Recall
  • Nutrition Assessment
  • Photography*
  • Size Perception*
  • Statistics, Nonparametric
  • Surveys and Questionnaires