Title The Effect of Minimum Instructional Hours at School and Childhood Weight. Authors Rahi Abouk, Francis Cai, Taghi Ramin, Tricia Snyder Abstract Researchers study the effect of minimum school instructional hours set by states on childhood overweight and obesity. Principal findings and recommendations In this study, we use state-level variations in the minimum amount of instructional time to study the effect of the amount of time spent at school on children’s physical health. We use the 2007 National Survey of Children’s Health (NSCH) which is a nationally representative sample of children below 18. In this survey, Body Mass Index (BMI) is reported for children aged 10-17. We find that for every 10 hours increase in the number of school hours, the likelihood of an African Americans child being overweight decline by close to 1.3%. A child is defined as overweight if his/her BMI is between 25 and 30. No effect where found among white children. The effect on African American children could be justified given that they more likely benefit from better health inputs at school compared with what is offered to them at home. However, this is not the case for white children. Overall, our research suggests that the amount of time spent at school could be a tool to fight childhood overweight.