Kids may have a whole new reason to skip school: A new study suggests that schoolwide food practices and policies can actually lead to weight gain in adolescents.

As reported in the Archives of Pediatric and Adolescent Medicine (2005; [159], 1111–14), researchers observed more than 3,000 eighth-graders from 16 middle schools in the Minneapolis-St. Paul area who participated in a school-based dietary intervention program. Also examined were the schools’ food policies and practices, including use of food for incentives, rewards and fundraising events.

The study found that in schools that supported frequent snacking and the consumption of high-calorie foods and beverages, the body mass index of students was higher. The researchers concluded that “prevention of overweight in childhood must include attention to the nutrition integrity of schools, and school nutrition policies that consistently support and promote healthy dietary practices among young adolescents are urgently needed.”