This study examined the effects of using "Physical Best" lessons to promote adolescent energy balance knowledge and task values. Seventh graders (N = 90) were randomly assigned to the experiment and the comparison groups. The experiment group took 10 selected "Physical Best" lessons, while the comparison experienced 10 district lessons. Pre- and post-measurements of knowledge and task values were taken at the beginning and the end of the experiment. Analysis of covariance and multivariate analysis of variance were conducted to test the difference over time and between the groups in energy balance knowledge test scores and task values. Both groups improved knowledge test scores, but the experiment group scored significantly higher than the comparison, controlling for the pre-test. The comparison group reported higher initial attainment values which declined over time, while the experiment group increased. The findings suggested that "Physical Best" lessons were effective (?[subscript p][superscript 2] = 0.18) in improving students' energy balance knowledge in 10 structured lessons, and that students reported a higher perceived value about the importance of physical education after they learned energy balance and exercise principles. Perhaps these concepts should be taught in physical education to improve student knowledge and perceived values of the subject.