A recent study published in the Archives of Pediatrics & Adolescent Medicine (June 2007) suggested that for obese middle-school children, school-based fitness interventions are an important part of their overall fitness. In fact, the extended summer break reduced their cardiovascular fitness, increased fasting insulin levels as well as body fat.
These results would suggest that the families of obese kids need some education and/or support to help their children make different choices about eating and exercise when home and not participating in school-based programs. Turning off the T.V. and getting active may need to be decisions made at an adult level with support for finding ways for preteens and teens to stay active and involved in non-sedentary activities.