Overall, low-income children participating in the NSLP display similar socioeconomically disadvantaged characteristics, despite different patterns of participation. Participation in the NSLP appears to be associated with the rate at which low-income girls gain weight compared with low-income girls who do not participate in the program. Although our study includes a measure of physical activity and television viewing, the results should be interpreted carefully because the measures are based on recall methods that are subject to social desirability bias.42- 44 Although physical activity recall methods are feasible and an inexpensive approach compared with objective measures (eg, accelerometers), previous research has indicated that females tend to overreport their physical activity.42,43,45 Our study also lacks information on dietary intake and consumption patterns during the school lunch period and outside the school environment, precluding us from examining the mechanisms by which these differences exist. Thus, it is unclear whether low-income children who are participating in the NSLP are actually consuming their lunch and/or consuming à la carte items. Future studies focusing on participation in food-assistance programs and children’s BMIs should include detailed information on the built environment, along with dietary intake, consumption patterns, and physical activity of income-eligible girls and boys, using both dietary recall techniques and objective measures (such as physiological monitoring). Efforts to gain a better understanding of what children are consuming and how often children are consuming particular foods in relation to environmental stressors may provide important new best practices on creating healthier lunch options for all children.