IntroductionCardiovascular prevention is more effective if started early in life, but available interventions to promote healthy lifestyle habits among youth have been ineffective. Impulsivity in particular has proven to be an important barrier to the adoption of healthy behaviors in youth. Observational evidence suggests that mindfulness interventions may reduce impulsivity and improve diet and physical activity. We hypothesize that mindfulness training in adjunct to traditional health education will improve dietary habits and physical activity among teenagers by reducing impulsive behavior and improving planning skills. Methods/design The Commit to Get Fit study is a pilot cluster randomized controlled trial examining the feasibility, acceptability and preliminary efficacy of school-based mindfulness training in adjunct to traditional health education for promotion of a healthy diet and physical activity among adolescents. Two schools in central Massachusetts (30 students per school) will be randomized to receive mindfulness training plus standard health education (HE-M) or an attention-control intervention plus standard health education (HE-AC). Assessments will be conducted at baseline, intervention completion (2 months), and 8 months. Primary outcomes are feasibility and acceptability. Secondary outcomes include physical activity, diet, impulsivity, mood, body mass index, and quality of life. Conclusions This study will provide important information about feasibility and preliminary estimates of efficacy of a school-delivered mindfulness and health education intervention to promote healthy dietary and physical activity behaviors among adolescents. Our findings will provide important insights about the possible mechanisms by which mindfulness training may contribute to behavioral change and inform future research in this important area.