Dose: Comparison of 6 and 12 Nutrition and Physical Activity Sessions Targeting Middle School Adolescents


  • Mical Kay Shilts California State University Sacramento
  • Anna C. Martin University of California Cooperative Extension
  • Marilyn S. Townsend California State University Davis



Determining optimal intervention dose to meet time constraints of the teacher while maximizing behavioral impact for students has proven challenging. This study investigated the influence of intervention dose on 7th & 8th grade participants’ dietary and physical activity (PA) behaviors. Participants were assigned randomly to a: 1) 6 week-12 session nutrition intervention [treatment#1], or 2) 3 week-6 session nutrition intervention [treatment#2] with data collected pre/post intervention. Using ANCOVA, measures assessed dietary and PA self-efficacy and behaviors. Ethnically diverse participants (n=107) were included in the analyses (46% male). All students set two goals: one dietary and one PA regardless of dose. Treatment#1 resulted in similar outcomes compared to treatment#2 with no significant differences between groups. As a result, we recommend that teachers using the 12 week intervention give students the option of setting new goals after the 6th lesson to maintain motivation.






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