British Journal of Nutrition

Full Papers

Children's estimates of food portion size: the effect of timing of dietary interview on the accuracy of children's portion size estimates

E. Fostera1 c1, M. O'Keeffea2, J. N. S. Matthewsa2, J. C. Mathersa1, M. Nelsona3, K. L. Bartona4, W. L. Wriedena4 and A. J. Adamsona1

a1 Human Nutrition Research Centre, School of Clinical Medical Sciences, University of Newcastle, Room M1151, 1st Floor, William Leech Building, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK

a2 School of Mathematics and Statistics, Newcastle University, Newcastle upon Tyne, UK

a3 Department of Nutrition and Dietetics, Kings College London, London, UK

a4 Centre for Public Health Nutrition Research, University of Dundee, Dundee, UK


For food intakes to be converted into nutrient intakes a measure or estimate of the amount of food consumed is required. A number of methods have been developed to assist subjects in providing an estimate of portion size. Children's ability to use perception, conceptualisation and memory skills to estimate food portion size has not been investigated systematically. The aim of the present study was to test the effect of the timing of a dietary interview on the accuracy of estimates of food portion sizes made by children, using food photographs, food models and an interactive portion size assessment system, developed for use with children and based on portion sizes of foods consumed by children. Children (n 108) aged 4–14 years were supplied with known quantities of foods and asked to estimate the portion size of each food using each of the three portion size assessment tools. Interviews took place (a) with the food in view, (b) just after the child had eaten the food or (c) 24 h after the child had eaten the food. There were no significant differences in children's ability to estimate food portion size (either as served or as eaten) with timing of interview. That is, children were as accurate in their estimates of portion size 24 h after consuming the food as when the food was in view. Under these conditions many children were able to estimate food portion size utilising perception, conceptualisation and memory skills.

(Received August 10 2006)

(Revised April 25 2007)

(Accepted April 30 2007)


c1 Corresponding author: Dr Emma Foster, fax +44 191 2225581, email


Abbreviations: FIF, food in front; IPSAS, interactive portion size assessment system; JAE, just after eating