Background: A 2010 publication showed a positive relationship between children's body mass index (BMI) and energy intake at school-provided meals (as assessed by direct meal observations). To help explain that relationship, we investigated 7 outcome variables concerning aspects of school-provided meals: energy content of items selected, number of meal components selected, number of meal components eaten, amounts eaten of standardized school-meal portions, energy intake from flavored milk, energy intake received in trades, and energy content given in trades. Methods: Fourth-grade children (N = 465) from Columbia, SC, were observed eating school-provided breakfast and lunch on 1 to 4 days per child. Researchers measured children's weight and height. For daily values at school meals, a generalized linear model was fit with BMI (dependent variable) and the 7 outcome variables, sex, and age (independent variables). Results: BMI was positively related to amounts eaten of standardized school-meal portions (p less than 0.0001) and increased 8.45 kg/m[superscript 2] per serving, controlling for other variables in the model. BMI was positively related to energy intake from flavored milk (p = 0.0041) and increased 0.347 kg/m[superscript 2] for every 100 kcal consumed. BMI was negatively related to energy intake received in trades (p = 0.0003) and decreased 0.468 kg/m[superscript 2] for every 100 kcal received. BMI was not significantly related to 4 outcome variables. Conclusions: Knowing that relationships between BMI and actual consumption, not selection, at school-provided meals explained the (previously found) positive relationship between BMI and energy intake at school-provided meals is helpful for school-based obesity interventions. (Contains 2 tables.)