Background: Encouraging adolescents to adopt healthy lifestyles can be challenging. The aim of the "Som la Pera" study was to engage adolescents by applying new strategies to increase both their fruit and vegetable consumption and their physical activity (PA), while reducing their sedentary behavior (screen time per day). Methods: In disadvantaged neighborhoods of Reus (Spain), two high schools were randomly assigned to the intervention (n = 169 adolescents, 13- to 16-year old) and two were assigned to the control group (n = 223 adolescents, 13- to 16-year old). The intervention, which lasted 12 months and spanned two academic years (2013-2015), used social marketing (SM) to improve healthy choices. The peer-led strategy involved 5 adolescents, who designed and implemented 10 activities as challenges for their 169 school-aged peers. The control group received no intervention. To assess self-reported lifestyles in both groups, the Health Behavior in School-aged Children survey was used at baseline and end of study. Results: After 12 months, the weekly PA improved in the intervention group vs. the control one (p = 0.047). When male and female groups were examined separately, the improvement in PA remained with a borderline significance only in the male group (p = 0.050). Conclusions: A school-based, peer-led SM intervention designed and implemented by adolescents attending high schools in low-income neighborhoods promoted an increase in PA, particularly in male adolescents 13 to 16 years of age. No effect on fruit or vegetable consumption or screen time was observed. Clinical Trial Registration number: NCT02157402.
Keywords: adolescent; lifestyle behaviors; obesity prevention; peer-led intervention; school based; social marketing.