Effectiveness Trial of a Dissonance-Based Obesity Prevention Program
- Conditions
- ObesityWeight GainEating Disorders
- Interventions
- Behavioral: Project HealthBehavioral: Healthy WeightBehavioral: Placebo Control
- Registration Number
- NCT01680224
- Lead Sponsor
- Oregon Research Institute
- Brief Summary
Obesity is a major US public health problem. Few obesity prevention programs have reduced risk for weight gain over follow-up and those that have are very intensive, making dissemination difficult and costly. A brief 3-hr selective prevention program (Healthy Weight) targeting young adults with body dissatisfaction involving participant-driven healthy dietary and physical activity lifestyle changes significantly reduced increases in body mass index (BMI) and obesity onset relative to alternative interventions and assessment-only controls through 3-yr follow-up, though effects were small in magnitude. To enhance efficacy, the investigators added dissonance-inducing activities regarding unhealthy dietary and activity practices, drawing from a highly efficacious dissonance-based eating disorder prevention program. A pilot trial found that this new Project Health intervention significantly reduced increases in BMI relative to both the Healthy Weight intervention and an educational brochure condition from pre to post. The investigators propose to conduct a rigorous multisite effectiveness trial that will test whether adding the dissonance-induction elements to the originally Healthy Weight intervention improves weight gain prevention effects. 360 college students at risk for future weight by virtue of their age and weight concerns will be randomized one of three conditions: (1) a refined 6-hr group-based dissonance-based Project Health, (2) a 6-hr group-based Healthy Weight intervention, or (3) a psychoeducational video ("Weight of the World") condition. Participants will complete assessments of % body fat, mediators (including objectively measured physical activity), moderators, and other outcomes at pre, post, and 6, 12, and 24 month follow-ups.
- Detailed Description
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).
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 364
- University student
- Presents with self-reported "weight concerns"
- Diagnosis of Eating Disorder
- Obese
- Underweight
- Non-english speaking
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description Project Health 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. Healthy Weight 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. Control Placebo Control Some participants will be randomized to control condition whereby they will be given an psychoeducational video ("Weight of the World")to view.
- Primary Outcome Measures
Name Time Method Body Fat Percentage 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.
- Secondary Outcome Measures
Name Time Method Food Craving/Liking 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?"
Eating Pathology 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 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).
Trial Locations
- Locations (4)
Oregon Research Institute
🇺🇸Eugene, Oregon, United States
Oregon State University
🇺🇸Corvallis, Oregon, United States
University of Texas, Austin
🇺🇸Austin, Texas, United States
University of Oregon
🇺🇸Eugene, Oregon, United States