Journal of sports sciences | 2021
Integrating needs-supportive delivery into a laboratory-based randomised controlled trial for adolescent girls with overweight and obesity: Theoretical underpinning and 12-week psychological outcomes.
Abstract
When designing efficacy trials, researchers have a responsibility to do no harm and to do good . Given the psychological vulnerability of adolescent girls with overweight and obesity, it is important to consider the implications of participating in weight-related research studies. We investigated psychological outcomes from a 12-week laboratory-based randomised controlled trial aimed at improving body composition and bone health in adolescent girls with overweight and obesity. Sixty-three participants were randomised to three groups (Recommended dairy diet plus exercise (RDa, n =\xa024); Low dairy diet plus exercise (LDa, n =\xa025); no-intervention control (n\xa0=\xa014)). Self-Determination Theory-informed strategies were applied in both intervention groups to foster motivation and enhance psychological wellbeing. Motivation, perceived competence and self-perceptions were measured at 0 and 12\xa0weeks. Fifty-four participants (24 RDa, 23 LDa, 7 Control) provided complete psychological data. There were no between group differences in 0- to 12-week change in motivation, perceived competence or global self-worth. Both intervention groups showed significant improvements in physical self-worth (p\xa0=\xa00.001), body satisfaction (p\xa0=\xa00.002) and perceived physical conditioning (p\xa0=\xa00.002), compared with the control group. A theory-informed, laboratory-based diet and exercise intervention produced favourable psychological outcomes for adolescent girls with overweight and obesity.