This randomized controlled trial assesses the efficacy of a 6-week, dissonance-based, weight-gain prevention program (Fit4Duty) designed to reduce unhealthy weight gain among military service members at-risk for obesity. The Fit4Duty program is an adaptation for the military of an existing civilian obesity prevention program, Project Health, which reduced obesity onset by 50% in healthy civilian young adults. Fit4Duty is compared to a nutrition education control condition and is hypothesized to reduce excess weight gain beyond the control comparison program during the 2 year period following study participation.

Obesity is prevalent in military personnel and raises concerns related to health, readiness, and national defense. Adverse health consequences of obesity place military personnel at risk for serious medical problems while in the service and upon discharge/retirement. Additionally, failure to "make weight" may negatively impact one's military career and can lead to discharge from the service. Early identification of personnel at risk and implementation of prevention strategies are critical to addressing the problem of overweight in the military and are essential to maintaining a fit fighting force. The goal of this study is to test the effectiveness of a dissonance-based, weight-gain prevention program (Fit4Duty) to prevent excess weight gain among service members at risk for obesity due to a personal and/or family history of overweight. The Fit4Duty program is an adaptation for the military of an existing civilian obesity prevention program, Project Health. The program utilizes dissonance based, participant-driven group counseling to address the excess consumption of unhealthy foods and sedentary behavior. Active duty service members will be randomized to the Fit4Duty weight gain prevention program or a Nutrition Education comparison condition. Participants will complete height, weight, and body composition measurements, and self-report instruments at baseline, immediately following the prevention program (6-weeks), and one and two year follow-ups. It is hypothesized that Project Fit4Duty will result in significantly greater reduction in risk for increases in BMI percentile and percent fat mass, and risk for onset of overweight and obesity during the 2-year follow-up relative to a nutrition education control program. If successful, Project Fit4Duty would offer an economical approach for widespread obesity prevention in the U.S. Military.

Inclusion Criteria:

• Active Duty Service Member
• 18.5 kg/m2 < BMI ≤ 32kg/m2
• At risk for excess weight gain due to personal and/or family history of overweight
• English speaking
• Ability to complete study procedures

Exclusion Criteria:

• Presence of a major, chronic medical illness
• Illness and/or treatment likely to affect appetite or body weight
• Planned deployment/ training during the intervention period (upcoming 2 months)
• Documented or self-reported current pregnancy, current breast-feeding, or recently pregnant women (within 1 year of delivery). Because pregnancy is a state in which weight gain is expected and appropriate, pregnant individuals would not be suitable for this study
• Evidence or signs of suicidal ideation as determined by the research team