We present findings from a field experiment conducted at 40 elementary schools involving 8000 children and 400,000 child-day observations, which tested whether providing short-run incentives can create habit formation in children. Over a 3- or 5-week period, students received an incentive for eating a serving of fruits or vegetables during lunch. Relative to an average baseline rate of 39%, providing small incentives doubled the fraction of children eating at least one serving of fruits or vegetables. Two months after the end of the intervention, the consumption rate at schools remained 21% above baseline for the 3-week treatment and 44% above baseline for the 5-week treatment. These findings indicate that short-run incentives can produce changes in behavior that persist after incentives are removed.