This 2-site effectiveness trial will test whether a brief dissonance-based obesity prevention program delivered in single sex groups combined with food response and attention training will produce significantly larger weight gain prevention effects than an educational video control condition. An effectiveness trial is important to test whether this program reduces risk for unhealthy weight gain when delivered by real world clinicians under ecologically valid conditions, which is an important step toward broad implementation. A secondary aim focuses on eating disorder symptom prevention effects. A sample of 17-20 year olds with weight concerns (N = 120) will be randomized to single sex Project Health groups with food response and attention training or an educational video control condition. Participants will complete assessments at baseline, posttest, and 6- and 12-month follow ups.

In the previous Project Health trial, the investigators found Project Health is most effective when implemented in single sex groups paired with food specific response and attention training. This project will evaluate the effectiveness of this version of the Project Health intervention compared to a video control condition and is an important step toward dissemination. A brief effective obesity prevention program that can be easily, inexpensively, and broadly implemented to late adolescents at risk for excess weight gain, as has been the case with another dissonance-based prevention program, could markedly reduce the prevalence of obesity and associated morbidity and mortality. The program may also have an important secondary benefit of preventing the onset of future eating symptoms and disorders. The study has 2 aims: (1) Test the hypothesis that Project Health implemented in single-sex groups and paired with food response inhibition and attention training produces significantly larger weight gain and overweight/obesity onset prevention effects than an educational video control condition (primary outcome). (2) Test the hypothesis that Project Health implemented in single-sex groups and paired with food response inhibition and attention training produces significantly larger eating disorder symptom prevention effects than an educational video control condition (secondary outcome).

Inclusion Criteria:

• Current at least moderate weight concerns (defined as a response of 4 or above on an 8 point scale ranging from none (0) to extreme (8))
• Self-reported room for improvement in diet and exercise habits (response of yes to "Do you believe there is room for improvement in your diet and exercise habits?" in the pre-screening questionnaire)
• BMI greater than or equal to 20 and less than or equal to 30
• Age between 17 and 20 years old

Exclusion Criteria:

• Current diagnosis of anorexia nervosa, bulimia nervosa or binge eating disorder
• Previous participation in a Project Health study

The investigators will share all study data via the NICHD Data and Specimen Hub (DASH), which is the centralized resource for researchers to store and access data from NICHD-funded research studies to use for secondary research. All data, with the exception of video recordings of the participants in treatment (which cannot be effectively de-identified), will be provided.

After all follow-up assessments are completed and the main project papers are published, a dataset stripped of identifiers prior to release will be made available without cost to researchers and analysts.

Outcome assessors will be masked to participant condition.