Secondary analyses of data from 4 studies with fourth-grade children show that sex, race, amounts eaten of standardized portions, and energy content given in trades explain the positive relationship between body mass index and energy intake at school-provided meals

Abstract Results from a 2012 article showed a positive relationship between children's body mass index (BMI) and energy intake at school-provided meals. To help explain that positive relationship, secondary analyses investigated (1) whether the relationship differed by sex and race and (2) the relationship between BMI and 6 aspects of school-provided meals—amounts eaten of standardized portions, energy content given in trades, energy intake received in trades, energy intake from flavored milk, energy intake from a la carte ice cream, and breakfast type. Data were from 4 studies conducted 1 per school year (1999-2000 to 2002-2003). Fourth-grade children (n = 328; 50% female; 54% black) from 13 schools total were observed eating school-provided breakfast and lunch on 1 to 3 days per child for 1178 total meals (50% breakfast). Children were weighed and measured. Marginal regression models were fit using BMI as the dependent variable. For purpose 1, independent variables were energy intake at school-provided meals, sex, race, age, and study; additional models included interaction terms involving energy intake and sex/race. For purpose 2, independent variables were the 6 aspects of school-provided meals, sex, race, age, and study. The relationship between BMI and energy intake at school-provided meals differed by sex ( P < .0001; stronger for females) and race ( P = .0063; stronger for black children). BMI was positively related to amounts eaten of standardized portions ( P < .0001) and negatively related to energy content given in trades ( P = .0052). Explaining the positive relationship between BMI and energy intake at school-provided meals may contribute to school-based obesity prevention efforts.