Comparison of Visual Estimates of Children's Portion Sizes Under Both Shared-Plate and Individual-Plate Conditions

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Abstract

Objective This paper compares the accuracy of visual estimations of children's food intake in settings where several children eat together off 1 plate vs individual-plate eating scenarios.

Design Eight trained observers were tested in their ability to estimate food portions consumed by children enacting common eating scenarios. Foods were categorized by food group and according to their presentation by individual-plate and shared-plate. Observed food weight estimates were compared to actual weights.

Subjects/setting The 8 observers visually estimated 69 food portions of children eating alone and 26 portions where children were eating from a shared plate. This study was carried out in Sarlahi District, a rural, central lowland region of Nepal.

Statistical analyses Pearson's correlation coefficients were calculated to examine associations between estimated and actual weights. A fixed effects model was constructed to compare observers.

Results Analyses revealed that observer estimates of food weights under field conditions were well correlated with actual weights for individual-plate (r=0.89) and for shared-plate (r=0.84) scenarios. Observers estimated food weights when children ate together on a shared plate less accurately than they did in settings where children ate alone. With the exception of 1 observer, observers did not differ signifi-cantly in their ability to estimate food weights. Accuracy of estimations was influenced by food weight with greater error associated with food quantities of less than 70 g.

Conclusions Visual estimation is a relatively accurate, valid method of assessing child food intake under rural field conditions, and the only method to obtain accurate informa-tion on dietary intake in regions where shared-plate eating is frequent. J Am Diet Assoc. 2001;101:47–52.

Section snippets

Methods

The validation study reported here was part of a larger longi-tudinal study of dietary behaviors and child health conducted in a rural district in the central plains of Nepal (16). The validation consisted of 17 separate field tests of 8 local workers trained in the use of structured observation. The field tests involved instances of shared-plate eating (where 2 or more children ate from a single plate) as well as individual-plate eating. All observers were Nepali men with a minimum of a high

Results

Table 1 summarizes the test data based on foods presented in individual-plate sessions by food group. As a percent of actual weight, dark green leafy vegetables and fruits were, on aver-age, more likely to be overestimated (141% and 139%). Mean observer estimates of grains and mixed foods were very close to actual (98% and 96%), respectively. One portion of dairy product observed was underestimated (76%).

Table 2 summarizes data based on foods presented in shared-plate sessions of groups of 2 or

Discussion

Assessing dietary intake under conditions where food is shared from a single plate has rarely been done in nutritional studies (7),(8). Our novel approach tests the validity of visual estimates and provides us with an approximation of the error associated with estimates obtained when food is shared or eaten individu-ally under circumstances that approximate true field condi-tions.Earlier work indicated that under controlled field conditions (within a classroom), observers with training were, on

Applications

■ Visual estimating of portion size is a feasible method of assessing intake under rural field conditions. This method is reasonably accurate, especially for larger food weights, and it is the only method that we are aware of that is suited to estimating food intake in populations where eating from a shared-plate is common. This is particularly important when attempting to assess the dietary intake of young children.

■ However, this method needs focused evaluations to assess accuracy and

References (23)

  • N.W Jerome et al.

    Integrating ethnographic research with nutrition studies

    Fed Proceed.

    (1981)
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