Effectiveness Trial of a Dissonance-Based Obesity Prevention Program
Condition: Obesity; Weight Gain; Eating Disorders
MeSH terms: Obesity; Weight Gain; Feeding and Eating Disorders
Study type: Interventional

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).
    

Intervention name(s): Healthy Weight; Project Health; Placebo Control
Intervention type(s): Behavioral; Behavioral; Behavioral
Intervention description(s): Participants will view a video on overweight and obesity
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Obesity; Weight Gain; Dissonance; College,University Students; Eating Disorders; Obesity Prevention; Selective Prevention; Effectiveness