Effect of variable energy served on 24-hour energy intake in 16 preschools, Chicago, Illinois, 2007

The effect of varying portion size in a natural environment on the self-regulation of 24-hour energy intake has not been evaluated. We studied students at 16 preschools in Chicago to determine the effect of meals with variable energy and macronutrients on the amount consumed over a 24-hour period (ie, at preschool and outside of preschool).

The food items and portion sizes served at 16 preschools in the Chicago Public Schools early childhood education programs were observed for 3 to 8 days. Children were assessed for total energy and selected macronutrients consumed at preschool and outside of preschool for a 24-hour period; their data were pooled and reported by school.

The students were predominantly African American (96%); on average, 32 students (range, 21-38) participated at each of the 16 preschools, and the age range of students was 4.0 to 4.5 years. The energy served at preschools ranged from 48% to 90% of the daily recommended energy allowance (REA). The mean energy intake at school was significantly higher (39% of REA) at 2 preschools, including 1 that served 90% of the REA. Mean energy consumption outside of preschool and total 24-hour energy consumption did not differ by preschool, adjusting for body mass index z score and sex.

The preschools served meals that widely varied by portion size and energy; however, this variation did not result in differences in mean 24-hour nutrient intakes for the students attending these schools.