Portion size estimation aids for Asian foods

Portion size estimation is fundamental to the accuracy of dietary recall, as well as interventions in obesity. Data on portion size estimation aids (PSEA) for Asian foods are limited. PSEA for Asian foods were developed and their accuracy and precision were tested for inclusion in a food atlas.

Sixteen food items were selected to represent all food groups. Small and life size photographs were developed, and line diagrams were drawn. These, together with household utensils, were tested among a random sample of 80 schoolchildren (aged 10-16 years). A total of 3180 estimations were made: 876 for small photographs (n = 11 foods), 558 for life size photographs (n = 7 foods), 1271 for line diagrams (n = 16 foods) and 475 for household utensils (n = 6 foods).

Line diagrams had a high percentage (63.9%) of correct estimations and a low percentage of over estimations (18.0%) and under estimations (18.1%), whereas household utensils performed poorly with 0.6% correct estimations. Greater accuracy and precision were obtained for amorphous foods with small photographs and for non-amorphous foods with line diagrams. The combination of small photographs (for vegetables) and line diagrams (for other foods) achieved a high correlation (r = 0.959, P ≤ 0.001), percentage correct estimations (68.3%) and low under estimations (19.9%) and over estimations (11.8%). Food texture, but not age or sex, was associated with correct estimations in all of the PSEA, except household utensils.

Accuracy and precision of a combination PSEA is convincing, enabling inclusion into an Asian food atlas for dietary assessment and intervention.