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Motivational Interviewing as an intervention to increase adolescent self-efficacy and promote weight loss: Methodology and design

Beverly Walpole1, Elizabeth Dettmer2, Barbara Morrongiello3, Brian McCrindle4 and Jill Hamilton5*

Author Affiliations

1 Department of Psychology, University of Guelph, Guelph, Canada

2 Hospital for Sick Children, Toronto, Canada

3 University of Guelph, Guelph, Canada

4 Division of Cardiology, Hospital for Sick Children, Toronto, Canada

5 Division of Endocrinology, Hospital for Sick Children, Toronto, Canada

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BMC Public Health 2011, 11:459  doi:10.1186/1471-2458-11-459

Published: 10 June 2011



Childhood obesity is associated with serious physiological and psychological consequences including type 2 diabetes, higher rates of depression and low self-esteem. With the population of overweight and obese youth increasing, appropriate interventions are needed that speak to the issue of readiness to change and motivation to maintain adherence to healthy behavior changes. Motivational Interviewing (MI) is a method of therapy found to resolve ambivalence, enhance intrinsic motivation and promote confidence in a person's ability to make behavior changes. While MI has shown promise in the adult obesity literature as effecting positive lifestyle change, little is known about the effectiveness of MI with overweight and obese youth. This study aims to: 1) demonstrate that MI is an effective intervention for increasing a person's self-efficacy; 2) demonstrate that exposure to MI will facilitate healthy behavior changes; 3) explore psychological changes related to participation in MI and 4) compare physiological and anthropometric outcomes before and after intervention.


The current investigation is a prospective study conducted with ongoing participants who regularly attend an outpatient pediatric care center for weight-loss. Overweight youth (BMI > 85th %ile) between the ages of 10 and 18 who meet eligibility criteria will be recruited. Participants will be randomly assigned to a control group (social skills training) or a treatment group (MI). Participants will meet with the therapist for approximately 30 minutes prior to seeing the dietician, over the course of 6 months. Participants will also undergo a full day assessment at the beginning and end of psychology intervention to evaluate body fat, and metabolic risk (screening for diabetes, high cholesterol, high blood pressure and fitness level). The paper and pencil portions of the assessments as well as the clinical testing will occur at baseline and at the conclusion of the intervention (6 months) with a repeat assessment 6 months following the completion of the intervention.


Results from this study are expected to enhance our understanding of the efficacy of MI with children and adolescents who are overweight or obese.

Trial registration

Current Controlled Trials #NCT00326404.