Nonsignificant relationship between participation in school-provided meals and body mass index during the fourth-grade school year.

Data from four cross-sectional studies involving fourth-grade children were analyzed to investigate the relationship between participation in school-provided meals and body mass index (BMI), and the effect observed energy intake has on that relationship. Participation and BMI data were available on 1,535 children (51% black; 51% girls) for 4 school years (fall 1999 to spring 2003; one study per school year) at 13 schools total. Direct meal observations were available for a subset of 342 children (54% black; 50% girls) for one to three breakfasts and one to three lunches per child for a total of 1,264 school meals (50% breakfast). Participation in breakfast, lunch, and combined (both meals on the same day) was determined from nametag records compiled for meal observations for each study. Weight and height were measured. A marginal regression model was fit with BMI as the dependent variable; independent variables were breakfast participation, lunch participation, combined participation, sex, age, race, and study. For the subset of children, observed energy intake at breakfast, lunch, and combined was included in additional analyses. Participation in breakfast, lunch, and combined was not significantly associated with BMI regardless of whether analyses included observed energy intake (P values >0.181). The relationship between observed energy intake at breakfast and lunch, separately and combined, with BMI was positive (P values <0.01). In conclusion, these results do not support a relationship between school-meal participation and BMI but do support a relationship between observed energy intake at school meals and BMI during fourth grade.