School food environments and practices affect dietary behaviors of US public school children. (Special Issue: The school food environment, children's diets, and obesity - findings from the third School Nutrition Dietary Assessment Study (Robert Wood

摘要

Background - Changes to school food environments and practices that lead to improved dietary behavior are a powerful strategy to reverse the childhood obesity epidemic. Objectives - To estimate the effects of school food environments and practices, characterized by access to competitive foods and beverages, school lunches, and nutrition promotion, on children's consumption of sugar-sweetened beverages, low-nutrient energy-dense foods, and fruits/vegetables at school. Design - Cross-sectional study using data from the third School Nutrition Dietary Assessment Study, a nationally representative sample of public school districts, schools, and children in school year 2004-2005. Data from school principals and foodservice directors, school menu analysis, and on-site observations were used to characterize school food environments and practices. Dietary intake was assessed using 24-hour recalls. Subjects/setting - The sample consists of 287 schools and 2,314 children in grades one through 12. Statistical analyses performed - Ordinary least squares regression was used to identify the association between school food environments and practices (within elementary, middle, and high schools) and dietary outcomes, controlling for other school and child/family characteristics. Results - Sugar-sweetened beverages obtained at school contributed a daily mean of 29 kcal in middle school children and 46 kcal in high school children across all school children. Attending a school without stores or snack bars was estimated to reduce sugar-sweetened beverage consumption by 22 kcal per school day in middle school children (P<0.01) and by 28 kcal in high school children (P<0.01). The lack of a pouring rights contract in a school reduced sugar-sweetened beverage consumption by 16 kcal (P<0.05), and no a la carte offerings in a school reduced consumption by 52 kcal (P<0.001) in middle school children. The most effective practices for reducing energy from low-energy, energy-dense foods were characteristics of the school meal program; not offering french fries reduced low-nutrient, energy-dense foods consumption by 43 kcal in elementary school children (P<0.01) and sugar-sweetened beverage consumption by 41 kcal in high school children (P<0.001). Conclusions - To improve children's diet and reduce obesity continued changes to school food environments and practices are essential. Removing sugar-sweetened beverages from school food stores and snack bars, improving a la carte choices, and reducing the frequency of offering french fries merit testing as strategies to reduce energy from low-nutrient, energy-dense foods at school.