Do School Lunches Contribute to Childhood Obesity?

The most recent figures show that 16 percent of children aged 6-11 are obese – almost twice the rate of overweight in the early 1980s. Although there are few straightforward policy tools to combat the high level of obesity, almost two thirds of school children eat a National School Lunch Program lunch, and consume about one-third of their total calories from this meal. Previous studies have established that the school lunch program lunches often fail to meet nutrition requirements, and have an especially high fat content. In this project, I assess whether the National School Lunch Program plays a role in the incidence of childhood obesity. I employ two methods to isolate the causal impact of school lunches on childhood overweight. First, using panel data from the Early Childhood Longitudinal Survey I find that children who consume school lunches are about 2 percentile points more likely to be obese than those who brown bag their lunches. But since both groups of children enter kindergarten with the same obesity rates, the panel data suggests that the difference in obesity rates is not merely a function of fixed differences between children who select into the school lunch program. Second, I leverage the sharp discontinuity in eligibility for reduced-price lunch – available to children from families earning less than 185 percent of the poverty rate – to compare children just above and just below the eligibility cutoff. Using this regression discontinuity approach, I find that students are more likely to eat school lunch, to be obese, and weigh more if they are income-eligible for reduced price school lunches. To assess the plausibility of these findings, I investigate the additional calories consumed by those in the school lunch program. Using food recall data, I find that children who eat school lunch consume 40-120 more calories at lunch than those who brown bag, but that both groups of children consume the same amount of calories the rest of the day (not including lunch). I estimate that for children an extra 40-120 calories per day would increase the incidence of overweight by 2 to 4 percentile points – the same as the observed increase in overweight. I estimate that if school lunches were made healthier and consistently met the nutrition requirements set for them, the childhood obesity rate would decline