Association for Public Policy Analysis & Management

A key concern for child health and development in the U.S. is the rapid increase in the prevalence of obesity among children. Genetic, metabolic, behavioral, environmental, cultural and socioeconomic factors all play a role in excess adiposity. With the rapid increase in the prevalence of obesity in the U.S. over a short time period, it is clear that behavior and environment are important elements. With children spending a significant amount of time each day in school, foods offered in school provide a viable policy lever for improving child nutrition and nutrition-related outcomes.

School lunches are provided through the National School Lunch Program (NSLP). In 2015, the federal government spent over $11.7 billion on the program and served lunches to over 30 million children daily. Lunches served contain one-third of the Recommended Energy Allowance for the day. The majority of the children served by NSLP live in low-income households disproportionately affected by obesity.

As directed by the Healthy, Hunger-Free Kids Act of 2010, USDA instituted new nutrition standards for lunches served to school children. These standards reflect the most recent Dietary Guidelines for Americans and are designed to lead to improvements in meal quality and nutrition-related child outcomes. Given that child obesity is a critical public health issue and the new school meal standards pose a significant public investment in bettering child nutrition, it is important to assess the effects of the new standards on child weight outcomes. To that end, this research has the following specific aim: to assess the association between implementation of the updated nutrition standards and child weight.

A non-experimental design and secondary data are used to estimate the association between the new nutrition standards on child BMI z-scores. Using nationally-representative data from the Early Childhood Longitudinal Studies—the 1998-1999 and 2010-2011 kindergarten cohorts—the goal of the quantitative analysis is to identify the factors that relate systematically to changes in BMI z-scores between the pre and post periods—and to assess the contribution of the NSLP nutrition standards. Difference-in-difference models are used to isolate the effect of the treatment on children consuming school meals, while controlling for possible biasing variables as well as time trends.

Results indicate that boys who ate school lunches after implementation of the updated standards experienced slower BMI z-score growth than did non-participants; participants’ BMI z-scores increased by 0.10 compared with 0.18 for non-participants. We find no evidence that school lunch participation is positively associated with third grade BMI z-scores after implementation of the revised standards for boys; in contrast, we find evidence of a positive relationship between school lunch participation and third grade BMI z-scores prior to implementation. We find no relationship between school lunch participation and BMI z-scores for girls.

This study provides evidence that the updated nutrition standards for school meals are associated with improved weight outcome for boys, but have no effect for girls, one year after implementation. These findings are encouraging and provide support for continued focus on improving the nutritional quality of school meals.