Effectiveness Trial of a Dissonance-Based Obesity Prevention Program (Project Health)
Behavioral: Healthy Weight
Behavioral: Project Health
Behavioral: Placebo Control
|Study Design:||Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Prevention
|Official Title:||Effectiveness Trial of a Dissonance-Based Obesity Prevention Program|
- Body Fat Percentage [ Time Frame: Changes in body fat from baseline to 2-year follow up ]We will use air displacement plethysmography (ADP) via the Bod Pod S/T to assess % body fat. Two measures will be averaged. Body density, calculated as body mass divided by estimated body volume, is used to calculate age- and gender-adjusted body fat percentile scores, based on normative reference data (McCarthy et al., 2006). A pilot validity study (N = 30) revealed that direct DEXA measures of % body fat correlates much more strongly with ADP estimates of body fat (r = .88) than with BMI (r = .23). Change in age- and gender-adjusted body fat percentile over the 2-year follow-up will be the primary outcome. This assessment takes 3-5 minutes to complete.
- Eating Pathology [ Time Frame: Baseline and post intervention (6 weeks); 6/12/24 month follow-up ]The Eating Disorder Diagnostic Interview, a brief semi-structured interview, will assess eating disorder symptoms. It provides diagnoses for anorexia nervosa, bulimia nervosa, and binge eating disorder, which will allow us to exclude participants with these disorders. It also provides a continuous measure of overall eating disorder symptoms.
- Negative Affect [ Time Frame: Baseline and post intervention (6 weeks); 6/12/24 month follow-ups ]The 20-item Negative Affect subscale of the Positive and Negative Affect Schedule (PANAS: Watson et al., 1988) measures general negative affectivity and depressive symptoms. Using a Likert rating system, participants choose their degree of endorsement of negative affectivity items such as "disgusted with self" and "lonely" (response options: 1 = not at all; 5 = extremely).
- Food Craving/Liking [ Time Frame: Baseline, 6 weeks (post intervention), 6/12/24 month follow ups ]The 28-item Food Craving Inventory (FCI; White et al., 2002) assesses subjective cravings for individual foods (pasta, ice cream), asking: "Over the past month, how often have you experienced a craving for the food?"
- Weighing Habits [ Time Frame: Baseline and post intervention (6 weeks); 6/12/24 mo follow-ups ]Participants will be asked how often they weighed themselves "in the past two weeks" at each assessment.
- Physical Activity [ Time Frame: Baseline and post-intervention (6 weeks); 6/12/24 month follow-ups ]Accelerometers will give objective measures of physical activity from each participant at each wave assessment.
|Study Start Date:||September 2012|
|Estimated Study Completion Date:||August 2017|
|Primary Completion Date:||June 2016 (Final data collection date for primary outcome measure)|
Active Comparator: Healthy Weight
The main goal of the Healthy Weight intervention is to make small, sustainable changes to input and output on a weekly basis to achieve a balance between caloric intake and output. All sessions begin with a brief review of what was covered in the previous session, presentation of educational handouts, careful review of previous behavior change goals, and the development of healthy behavior change plans for the next session. Home exercises for all sessions consist of following individualized diet and exercise goals, and keeping a food and exercise log to determine areas for future healthy changes.
|Behavioral: Healthy Weight|
Experimental: Project Health
Project Health adds dissonance-inducing activities, discussions, and homework activities to the Healthy Weight basic intervention. Each session begins with a verbal commitment to participate (to underscore the voluntary nature of participation), includes discussions of completed home practice assignments and in-session writing/sharing exercises (to create accountability), and concludes with home exercises (to increase level of effort). Completed home assignments are videotaped in subsequent sessions to increase accountability.
|Behavioral: Project Health|
Placebo Comparator: Control
Some participants will be randomized to control condition whereby they will be given an psychoeducational video ("Weight of the World")to view.
Behavioral: Placebo Control
Participants will view a video on overweight and obesity
Aim 1 will test the hypothesis that Project Health significantly reduces increases in % body fat relative to the Healthy Weight intervention and video control condition during a 2-yr follow-up; secondary outcomes are BMI, depressive symptoms and eating disorder symptoms. The investigators will also compare Healthy Weight to video controls.
Aim 2 will test the hypothesis that Project Health participants will experience increased cognitive dissonance (an uncomfortable psychological state) regarding eating unhealthy foods and engaging in sedentary behaviors, and that changes in dissonance mediate the program's weight gain prevention effects. The investigators will also test whether reduced calorie intake and increased physical activity mediate the effects of Project Health on change in % body fat.
Aim 3 will test the hypothesis that intervention effects are amplified for participants with elevated body dissatisfaction (which should increase motivation change) and preference for consistency (which should maximize dissonance induction) and mitigated for participants who report emotional eating and substance use (because these factors increase risk for overeating).
Please refer to this study by its ClinicalTrials.gov identifier: NCT01680224
|United States, Oregon|
|Oregon State University|
|Corvallis, Oregon, United States, 97331|
|University of Oregon|
|Eugene, Oregon, United States, 94703|
|Oregon Research Institute|
|Eugene, Oregon, United States, 97403|
|United States, Texas|
|University of Texas, Austin|
|Austin, Texas, United States, 78713|
|Principal Investigator:||Eric Stice, PhD||Oregon Research Institute|
|Study Director:||Paul Rohde, PhD||Oregon Research Institute|
|Study Director:||Heather Shaw, PhD||Oregon Research Institute|
|Study Director:||Kyle Burger, PhD||Oregon Research Institute|
|Study Director:||Nathan Marti, PhD||Oregon Research Institute|