Self-efficacy or Planning? Effects of a Change in Cognitions on Adolescents’ Behavior and Body fat
1University of Social Sciences and Humanities, Department of Psychology Wroclaw, Poland
2University of Colorado, Trauma Health and Hazards Center, Colorado Springs, USA
3Curtin University, School of Psychology and Speech Pathology, Perth, Australia
Background: The study tested the influence of intervention promoting exercise and healthy diet on behaviors and body fat among adolescents. We evaluated the effects of three types of interventions (addressing self-efficacy, planning, and a combination of planning and self-efficacy), compared to changes in a control (education) group. Methods: Data were collected among 1258 adolescents (aged 14-18; 22.1% overweight), who were allocated to four study groups. Behavior, cognitions, body weight, height, and fat tissue were assessed at three measurement points (the baseline, 2-, and 14-month follow-ups). Findings: Significant effects on physical activity were found in the intervention groups which included self-efficacy component. A reduction in body fat at 14-month follow-up was observed in overweight girls participating in self-efficacy or combined (planning + self-efficacy) groups. Among overweight boys, a significant decrease in body fat was found in the combined intervention group. The effects were mediated by changes in self-efficacy and physical activity. Discussion: Self-efficacy was identified as the active ingredient of a healthy lifestyle promotion intervention for adolescents.