Progress 08/01/06 to 07/31/07
Outputs
OUTPUTS: Two published investigations of portion size in children demonstrate that large portions result in increased intake at meals. The influence of large portions on children's own self-selected servings is unknown. Among adults, the amount of food available and size of eating implements (i.e. bowls, utensils) influences the amount selected and consumed. An experiment was conducted at the USDA/ARS Children's Nutrition Research Center at Baylor College of Medicine in Houston TX. This research used a 2 x 2 within-subjects design to test effects of the amount of a pasta entree available (275 g vs. 550 g) and serving spoon size (teaspoon vs. tablespoon) on young children's self-served entree portions and intake at a dinner meal. Participants were 61 (33 female and 28 male; 26 Hispanic, 17 black, 14 white, 4 Asian; 13 with BMI gt 85th percentile) 5- to 6-year-old children. Condition sequence was randomly assigned and each condition was spaced one week apart in a laboratory setting
with groups of 3-4 children eating together. Each child was given an individual serving dish containing the entree and serving spoon along with an empty plate and fixed portions of other familiar foods on a tray. Self-served entree portions and entree intake were determined using weighed servings and intakes. Demographics, feeding styles, and maternal and child body mass index were measured. Mixed models, taking into account social groups at tables, were utilized. A second experiment involving self-selected portion size in children was conducted at the Pennsylvania State University in University Park, PA. How do children 'know' how much is enough? Recent evidence demonstrates that children do not always increase intake when entree portion sizes are increased. Inconsistencies across experimental studies of portion size highlight the arbitrary nature of large portion sizes. The study objective was revised from the original plan to evaluate two issues: (1) to identify the size at which
entree portions become excessive by evaluating children's entree intake across six increasing sizes including portions both smaller and larger than recommended amounts and (2) to determine the correspondence between children's self-served entree portion size and their response to increasing entree sizes. Participants were 17 3- to 5-y-old children. Using a within subject design all children were seen in all conditions. Energy intake was evaluated during a series of 6 lunches, in which 6 different portion sizes (100, 160, 220, 280, 340 and 400 of an entree (macaroni and cheese) were served in random order. Fixed portions of other foods (milk, green beans, and applesauce) were provided. Children's BMI: weight (kg) / height (m2) and age and sex specific BMI %iles were calculated using measured heights and weights.
PARTICIPANTS: Undergraduate and graduate students participated in collecting the data at the USDA/ARS Children's Nutrition Research Center and the Pennsylvania State University.
PROJECT MODIFICATIONS: The third objective of the study was revised. The original objective of experiment 3 was to determine the effects of repeated exposure to the ED of foods on children's self-selected portions. The revised objective was to determine the association of children's self-served entree portion with their intakes across six increasing entree portion sizes. The objective was revised because recent evidence demonstrates that children do not always increase intake when entree portion sizes are increased. Inconsistencies across experimental studies of portion size highlight the arbitrary nature of large portion sizes. The study objective was revised: (1) to identify the size at which entree portions become excessive by evaluating children's entree intake across six increasing sizes including portions both smaller and larger than recommended amounts and (2) to determine the correspondence between children's self-served entree portion size and their response to increasing
entree sizes.
Impacts
Two behavioral experiments on children's self-served portion sizes lead to changes in knowledge of environmental influences on children's eating. The first experiment was designed to evaluate the influence of the amount of food available and serving spoon size on children's self-determined portion size. Across experimental conditions, greater self-served entree portions were seen in male and non-Hispanic black children, those with mothers reporting unemployment, and those with mothers reporting indulgent or authoritarian feeding styles. Self-served entree portions increased when the amount of food available was experimentally doubled but was not influenced by serving spoon size. Entree intake, however, did not differ by condition. However, children who selected more of the entree when more was made available also ate more of the entree. These findings provide new evidence that the amount of food available influences the size of children's self-served entree portions,
but does not have a uniform effect on intake. These results also point to social influences on children's self-determined portion sizes. The second experiment was designed to determine the size at which entree portions become excessive by evaluating children's entree intake across six increasing sizes including portions both smaller and larger than recommended amounts. A second objective was to determine the correspondence between children's self-served entree portion size and their response to increasing entree sizes. Energy intake of the entree and total energy intake at lunch increased significantly with increasing portion size, across portion sizes from 100 to 400 g. Children had a mean BMI %ile of 74.58. Children with BMI %iles values above the 85th percentile showed greater rates of increase in energy intake with increasing portion size than children with BMI values below the 85th percentile. Sixteen children participated in the self-served portion session. The minimum a child
served was 70 g and the maximum was 392 g. The mean portion they served themselves was 276.9 g, and the standard deviation was 97 and the mean portion that they ate was 232 g (SD=93 g). The quantity of macaroni and cheese eaten (g) during the self-serve portion session was significantly correlated to the quantity that they served themselves on that day. Children's who served themselves greater amounts of macaroni and cheese during the self-serve portion session also showed greater intakes of macaroni and cheese across six other conditions in which the amount of entree served to each child was incrementally increased. Finally, the self-served quantity of macaroni and cheese was correlated with child's BMI percentile. These results indicate that children respond to increasing portion size across a wide range of portions by increasing their intake a dose response fashion and the relation between portion size and energy intake was stronger for children with higher BMI percentiles, who
were at greater risk for overweight. Self-served portion sizes were positively related to BMI and children's intake of increasingly large entree portions.
Publications
- No publications reported this period
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