Association Between School Food Environment and Practices and Body Mass Index of U.S. Public School Children


The third School Nutrition Dietary Assessment Study (SNDA-III) enables researchers to hone in on specific components of the school food environment that contribute to child obesity.

Body Mass Index (BMI) is the accepted index for classifying adiposity (fatness). More than 20 percent of the children in the SNDA-III sample were obese. This report probed the statistical landscape of SNDA-III using a calibrated set of independent variables. The statistical model included a variety of school characteristics and an extensive demographic background for the students in the sample.

Key Findings:

  • For elementary schools, the presence of French fries in school lunches more than once per week and the availability of dessert more than once per week were each associated with significantly higher probabilities for obesity.
  • Among middle school students, the presence of low-nutrient, energy-dense foods in vending machines in or near the cafeteria was associated with significantly higher scores for a component of measuring BMI, the BMI z score.

The Child Nutrition and WIC Reauthorization Act of 2004 required the development of school wellness policies. Where feasible, future research should track BMI/obesity before and after specific changes to school food practices.