Policy instruments used by States seeking to improve school food environments.

US legislatures and program administrators have sought to control the sale of foods offered outside of federally funded meal programs in schools, but little is known about which policies, if any, will prevent obesity in children. We used a theoretical policy science typology to understand the types of policy instruments used by US state governments from 2001 to 2006. We coded 126 enacted bills and observed several types of instruments prescribed by state legislatures to influence the foods sold in schools and improve the school food environment. Our study helps to better understand the various instruments used by policymakers and sets the stage to examine the effectiveness of the policy instruments used to prevent obesity.