Do School Lunches Contribute to
Diane Whitmore Schanzenbach
University of Chicago
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.
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.
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
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
Many thanks go to Kristin Butcher, David Card, John Cawley, Dan Eisenberg, Art Goldsmith, Hilary
Hoynes, Sarah Reber and seminar participants at the University of Chicago, University of Illinois, Federal
Reserve Bank of Chicago, Princeton, and especially the annual meeting of the Scholars in Health Policy
Research meeting for helpful comments.
Generous financial support from the Robert Wood Johnson
Foundation and the Center for Human Potential and Public Policy is gratefully acknowledged.