Association Between State Laws Governing School Meal Nutrition Content and Student Weight Status Implications for New USDA School Meal Standards

Importance: This study assessed whether stronger school meal nutrition standards may improve student weight status. Results have immediate implications because of the ongoing implementation of new nutrition standards for the National School Lunch Program. Objective: To determine if state laws with stricter school meal nutrition standards are inversely associated with adolescent weight status, while controlling for unmeasured state-level confounders. Design: Quasi-experiment. Setting: Public schools. Participants: Four thousand eight hundred seventy eighth-grade students in 40 states. Students were categorized by type of school lunch they usually obtained (free/reduced price, regular price, or none). Interventions: State laws governing school meal nutrition standards. States with standards that exceeded US Department of Agriculture (USDA) school meal standards were compared with states that did not exceed USDA standards. The parameter of interest was the interaction between state laws and student lunch participant status, ie, whether disparities in weight status between school lunch participants and nonparticipants were smaller in states with stricter standards. Main Outcome Measures: Body mass index percentile and obesity status. Results: In states that exceeded USDA standards, the difference in obesity prevalence between students who obtained free/reduced-price lunches and students who did not obtain school lunches was 12.3 percentage points smaller (95% CI, -21.5 to -3.0) compared with states that did not exceed USDA standards. Likewise, differences in mean body mass index percentile between those student populations were 11 units smaller in states that exceeded USDA standards (95% CI, -17.7 to -4.3). There was little evidence that students compensated for school meal laws by purchasing more sweets, salty snacks, or sugar-sweetened beverages from other school venues (eg, vending machines) or other sources (eg, fast food). Conclusions and Relevance: Stringent school meal standards that reflect the latest nutrition science may improve weight status among school lunch participants, particularly those eligible for free/reduced-price lunches.