Association of the universal free school lunch program with body mass index among Korean high school students, 2018-2021

Abstract

Background: We aimed to analyze the association between universal free school meal (UFSM) and body mass index (BMI) among Korean high school students, compared to selective free school meal programs for low-income households (conventional school meal [CSM] programs). Methods: Data from Korea Youth Risk Behavior Web-based Survey (KYRBS) conducted in 2018–2021 were utilized. We analyzed the likelihood of being underweight, overweight and obese before and after the UFSM introduction using multinomial logistic regression. The annual meal expenses per one student borne by school foodservice were considered. The year, grade, family composition, economic status, academic performance, eating habits, physical activity, sedentary time, sleep duration, self-reported health status, perceived stress level, drinking status, and smoking status were adjusted. Results: This study included 85,043 high school students from KYRBS were analyzed, including 43,424 boys (51.1%) and 41,619 girls (48.9%). Only girls under the UFSM program showed a higher likelihood of being overweight and obese (adjusted odds ratio: 1.181, confidence interval = 1.066–1.308). Female students with middle and high economic status and under the UFSM program had higher likelihood of overweight and obesity compared with those under the CSM program. Both male and female participants under the UFSM program with high meal expenses had higher likelihood of overweight and obesity. Conclusions: UFSM could be associated with adolescent overweight and obesity, particularly in girls. Due to possible concerns about overnutrition, further assessment and appropriate intervention should be considered.