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Motivational Interviewing for Weight Loss

This study has been completed.
Information provided by (Responsible Party):
Jill Hamilton, The Hospital for Sick Children Identifier:
First received: November 11, 2010
Last updated: March 15, 2014
Last verified: March 2014
The investigators studied the effect of motivational interviewing (MI) on self-efficacy, health behaviors, and health outcomes in overweight children and adolescents (ages ranging from 10 to 18 years).

Condition Intervention
Childhood Obesity
Behavioral: Motivational Interviewing (Treatment Group)
Behavioral: Social Skills Training (Control Group)

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single Blind (Participant)
Primary Purpose: Treatment
Official Title: Motivational Interviewing as an Intervention to Increase Adolescent Self-Efficacy and Promote Weight Loss

Resource links provided by NLM:

Further study details as provided by The Hospital for Sick Children:

Primary Outcome Measures:
  • Weight Efficacy Life-style Questionnaire [ Time Frame: Baseline, 6 month follow-up ]

    A self-efficacy instrument, the Weight Efficacy Life-style Questionnaire (WEL; Clark, Abrams, Niaura, Eaton, & Rossi, 1991) was used to measure participants' beliefs about and confidence in their own ability to make a behavior change, specifically their ability to lose weight.

    The questionnaire yields a total score, with higher scores indicating higher levels of health-related self-efficacy, as well as 5 situational sub-scores (negative emotions, availability, social pressure, physical discomfort, and positive activities). Individuals rate statements on a 10-point scale ranging from 0 (not confident) to 9 (very confident).

    The WEL is made up of 20 items (4 items per sub-scale) which are summed to obtain a total score, with the lowest total score possible being 0 and the highest 180. Only the total WEL score was used in the study's analyses.

    The difference in self-efficacy (WEL) change between treatment and control groups from baseline to a 6 month follow-up was examined.

  • Child Dietary Self-Efficacy Scale [ Time Frame: Baseline, 6 month follow-up ]

    A second self-efficacy scale, the Child Dietary Self-Efficacy Scale (CDSS; Parcel et al., 1995) was used to measure participants' confidence in their ability to choose lower fat, lower sodium foods.

    The questionnaire is made up of 20 likert items with 3 response options, including "not sure", "a little sure", and "very sure". Each item asks the participant to indicate how sure he/she is that they would make a healthy choice, for example, "How sure are you that you could eat cereal instead of a donut?" Individual items are scored -1, 0, or 1 and subsequently summed for a total score, with the lowest possible score a -20 and the highest a 20, whereby higher scores signify higher dietary self efficacy.

Secondary Outcome Measures:
  • Physiological Outcomes: BMI [ Time Frame: Baseline, 6 month follow-up ]
    The study used a Body Mass Index (BMI) percentile for age as the main indicator of weight-loss. Height and weight was measured by the pediatrician at the treatment site and BMI as well as BMI percentile for age was determined with the use of an age appropriate growth curve chart.

  • Physiological Outcomes: Waist Circumference [ Time Frame: Baseline, 6 month follow-up ]
    Measurements of waist circumference, an indirect measure of central adiposity (or fatness), were also obtained.

  • Psychological Well-being [ Time Frame: Change over time from Baseline to 6 months (measured monthly) with a 12 months reassessment ]
    Rosenberg Self-Esteem scale, Pediatric Quality of Life Inventory (PEDS QL), Child depression inventory, Adolescent coping (A-COPE)

Enrollment: 40
Study Start Date: September 2010
Study Completion Date: November 2012
Primary Completion Date: July 2012 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Motivational Interviewing Group
For the Motivational Interviewing (MI) treatment group, a clinical psychology doctoral student trained in Motivational Interviewing administered six individual motivational interviewing treatment sessions, each 30 minutes in length.
Behavioral: Motivational Interviewing (Treatment Group)
Motivational interviewing (MI) can be defined as a client-centered, directive method of therapy for enhancing intrinsic motivation to change by exploring and resolving ambivalence (Miller and Rollnick, 2002). MI manifests through specific strategies, such as reflective listening, summarization, shared decision making, and agenda setting.
Active Comparator: Control Group
The comparison group received six social skills training sessions instead of Motivational Interviewing (MI).
Behavioral: Social Skills Training (Control Group)
Within the social skills training framework, advice is given to clients and sessions are focused on assigning goals for clients to work towards without specific regard for their readiness to change. The intervention is aimed at finding appropriate ways to navigate typical social situations (e.g., how to negotiate with parents).

Detailed Description:

One empirically supported intervention with a large evidence base for improving adult outcomes in behavioral health-related disorders is Motivational Interviewing (MI). MI is strongly rooted in the client-centered therapy of Rogers (1951). Its relational stance emphasizes the importance of understanding the client's internal frame of reference and displaying unconditional positive regard for the client. Motivational interviewing can thus be defined as a client-centered, directive method of therapy for enhancing intrinsic motivation to change by exploring and resolving ambivalence. MI manifests through specific strategies, such as reflective listening, summarization, shared decision making, and agenda setting.

Adolescent participants exposed to motivational interviewing in conjunction with usual care (diet and exercise program) are expected to endorse greater self-efficacy, report increased engagement in healthy behaviors, demonstrate a decrease in body weight and report improved psychological outcomes. While motivational interviewing has been shown to increase adults' motivation to make healthy behavior changes, few adolescent studies have demonstrated this effect.


Ages Eligible for Study:   10 Years to 18 Years   (Child, Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Obese youth (with Body Mass Index (BMI) ≥ to 85th percentile for age and gender (as classified by the Center for Disease Control))
  • ages 10-18 years
  • attending a local obesity clinic ("Healthy Weights" clinic)

Time of entry into the weight-loss program was controlled for; however, both new and current participants had the option to participate in the study.

Exclusion Criteria:

  • taking medication whose side effects may influence weight gain or weight loss
  • did not speak English
  • demonstrated a developmental delay
  • reported being pregnant and/or reported having an eating disorder
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01246349

Canada, Ontario
The Hospital for Sick Children
Toronto, Ontario, Canada
Sponsors and Collaborators
The Hospital for Sick Children
Principal Investigator: Jill Hamilton, MD The Hospital for Sick Children
  More Information

Responsible Party: Jill Hamilton, Staff Endocrinologist, The Hospital for Sick Children Identifier: NCT01246349     History of Changes
Other Study ID Numbers: 1000017625
Study First Received: November 11, 2010
Results First Received: January 17, 2014
Last Updated: March 15, 2014

Keywords provided by The Hospital for Sick Children:
Motivational Interviewing
Child and Adolescent Self-Efficacy
Health Behaviours

Additional relevant MeSH terms:
Weight Loss
Pediatric Obesity
Body Weight Changes
Body Weight
Signs and Symptoms
Nutrition Disorders
Overweight processed this record on May 24, 2017