Explaining the positive relationship between fourth-grade children's body mass index and energy intake at school-provided meals (breakfast and lunch)

Improving the school food environment for the prevention of childhood obesity: What works and what doesn't

The food environment has a significant influence on dietary choices, and interventions designed to modify the food environment could contribute to the prevention of childhood obesity. Many interventions have been implemented at the school level, but effectiveness in addressing childhood obesity remains unclear. We undertook a systematic review, a meta-analysis, and meta-regression analyses to assess the effectiveness of interventions on the food environment within and around schools to improve dietary intake and prevent childhood obesity. Estimates were pooled in a random-effects meta-analysis with stratification by anthropometric or dietary intake outcome. Risk of bias was formally assessed. One hundred papers were included. Interventions had a significant and meaningful effect on adiposity (body mass index [BMI] z score, standard mean difference: -0.12, 95% confidence interval: 0.15, 0.10) and fruit consumption (portions per day, standard mean difference: +0.19, 95% confidence interval: 0.16, 0.22) but not on vegetable intake. Risk of bias assessment indicated that n = 43 (81%) of non-randomized controlled studies presented a high risk of bias in the study design by not accounting for a control. Attrition bias (n = 34, 79%) and low protection of potential contamination (n = 41, 95%) presented the highest risk of bias for randomized controlled trials. Changes in the school food environment could improve children's dietary behavior and BMI, but policy actions are needed to improve surrounding school food environments to sustain healthy dietary intake and BMI.

Milk Options Observation (MOO): A Mixed-Methods Study of Chocolate Milk Removal on Beverage Consumption and Student/Staff Behaviors in a Rural Elementary School

Providing flavored milk in school lunches is controversial, with conflicting evidence on its impact on nutritional intake versus added sugar consumption and excess weight gain. Nonindustry-sponsored studies using individual-level analyses are needed. Therefore, we conducted this mixed-methods study of flavored milk removal at a rural primary school between May and June 2012. We measured beverage selection/consumption pre- and post-chocolate milk removal and collected observation field notes. We used linear and logistic mixed models to assess beverage waste and identified themes in staff and student reactions. Our analysis of data from 315 unique students and 1,820 beverages choices indicated that average added sugar intake decreased by 2.8 g postremoval, while average reductions in calcium and protein consumption were negligible (12.2 mg and 0.3 g, respectively). Five thematic findings emerged, including concerns expressed by adult staff about student rebellion following removal, which did not come to fruition. Removing flavored milk from school-provided lunches may lower students' daily added sugar consumption without considerably decreasing calcium and protein intake and may promote healthy weight.

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

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.