Encouraging replacing energy-dense food intake with fruits and vegetables: effects of self-efficacy and planning interventions

Abstract

Background: This study compared effects of self-efficacy and planning interventions, encouraging fruit and vegetable intake (FVI) in place of energy-dense foods. Methods: Data were collected among 506 adolescents (13-18 years old; 22% with overweight/obesity) who were randomly assigned to control (n = 181), planning (n = 153), or self-efficacy (n = 172) conditions. Nutrition behaviors and cognitions were self-reported whereas body weight, height and body fat tissue were objectively measured three times (with the 2-month and 14-month follow-ups). Findings: Similar significant increase of FVI was found for self-efficacy and planning interventions (small-to-medium effects). Planning intervention did not influence dense-energy food intake, but the self-efficacy intervention tended to result in stabilizing intake (compared to an increase found in the control group). There were no effects on body mass. Similar patterns were found for the total sample and for a subsample of adolescents with overweight/obesity. The effects of interventions on FVI were mediated by respective cognitions. Discussion: The findings are discussed in the context of the effectiveness of behavior change techniques and best practice characteristics in interventions addressing obesity prevention and treatment.