Promotion of Exercise and Health in Obesity

Study Overview
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Brief Summary
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The primary objectives of this randomized clinical trial are a) to implement and test the impact of a 1-year lifestyle obesity treatment program based on Self-Determination Theory on 3-year change in physical activity and motivation for exercise/physical activity, body weight and fat, and selected eating variables, b) to identify behavioral and psychosocial theory-based moderators or mediators of primary outcomes, especially physical activity and body weight.

Detailed Description
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Obesity and sedentary lifestyles are worldwide threats to public health but feasible and effective strategies to tackle these problems are scarce. The identification of variables that explain why only a sub-group of overweight persons succeeds at increasing physical activity and achieving long-term weight control is a key research topic in exercise and sports sciences. Subjects are 260 healthy women (BMI, 25 to 40 kg/m2), aged between 25 and 50 years, premenopausal, of whom half receive the treatment intervention, the remaining being randomly assigned to a control group at baseline. This RCT consists of a 1-year intervention plus a 2-year no contact follow-up period. The intervention group attended 30 weekly group sessions, designed to follow SDT basic tenets, covering PA, eating/nutrition, body image, and other cognitive and behavioral contents. Central to the intervention model are autonomy, intrinsic motivation, and self-regulation of behavior change. Autonomy-supportive treatment climate and internal causality orientations are predicted to enhance autonomous regulation, perceived competence, and intrinsic motivation for the targeted behaviors, resulting in lasting behavioral and body weight changes. The intervention was designed to follow SDT, with an emphasis on promoting intrinsic, self-regulated motivation for exercise and weight control. The control group received a general health education curriculum based on several 3- to 6-week long educational topics (e.g. food safety, stress management, self-care, body image, and others). Results are expected to contribute to a better understanding of how individual characteristics, particularly those related to physical activity and exercise influence success, better screening/readiness testing procedures, improved matching of interventions to participants, and lower rates of attrition and unsuccessful weight loss attempts.

Official Title
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Moderators and Mediators of Physical Activity, Body Weight, and Body Composition Change During Obesity Treatment in Women

Conditions
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Obesity

Intervention / Treatment
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* Behavioral: SDT and Motivational Interviewing in Obesity Treatment


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: female (25-50 years old) pre-menopausal BMI between 25 and 40 kg/m2 willing to attend weekly meetings (during 1 year) willing to not participate in other formal or informal weight loss program during the first year of the study (intervention group only). Exclusion Criteria: major/chronic illness taking (or having taken in the previous year) medication known to interfere with body weight regulation, including anti-depressive medication

Ages Eligible for Study
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Minimum Age: 25 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: SDT Intervention<br>This arm will follow main experimental intervention, as described elsewhere | Behavioral: SDT and Motivational Interviewing in Obesity Treatment<br>* Thirty group sessions, designed to follow SDT, covering PA, eating/nutrition, body image, and other cognitive-behavioral contents. Central to the intervention are improving autonomy, intrinsic motivation, and self-regulation of behavior change. Accepting ambivalence for change, rolling with resistance, and developing discrepancy were used throughout the program, with an emphasis on promoting intrinsic, self-regulated motivation for exercise and weight control.<br>* Other names: GI: Intervention Group;|
| No Intervention: Comparison Group<br>Comparison Group receiving standard care health promotion intervention | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Primary outcomes are physical activity/exercise and body weight/ composition. Physical activity is assessed by accelerometry and standardized interview/questionnaire methods. Body composition is assessed by DXA |  | baseline, 4, 12, 16, 24 and 36 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Dietary Intake, psychosocial SDT-based mediators |  | baseline, 4, 12,16, 24 and 36 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Behavioral,, Self-Determination Theory,, Motivational Interviewing,, Exercise, Physical Activity,, Motivation,, Moderators,, Mediators,, Predictors,, Weight