NoWeigh: Development of a Physical Activity Promotion Mobile App for WomenBased on Body Neutrality and Self-Determination Theory - Some experts predict that severe obesity (≥40 kg/m2) will be the most common category for women by 2030. Weight loss has been the primary recommendation for managing comorbidities with obesity, such as elevated blood lipids and glucose, despite ample evidence that weight loss attempts generally lead to weight regain and weight cycling, which are associated with negative mental health outcomes like anxiety and depression. Experts have called for non-weight loss obesity management, by emphasizing health behaviors such as physical activity (PA). An effective method to deliver PA interventions is via mobile apps, of which women are the most frequent users, but most PA apps emphasize weight loss. We propose a novel framework for a PA promotion app, body neutrality, which does not emphasize weight or aesthetics but rather gratitude for the body’s function, a neutral attitude about the body’s appearance, and engaging in movement that is enjoyable. Self-Determination Theory of motivation (SDT), a widely used framework for PA interventions, aligns well with body neutrality. Both focus on moving away from external motivation for PA (i.e. appearance) and towards autonomous motivation (i.e. enjoyment of PA). We propose to show the feasibility of a mobile app that uses both body neutrality and SDT to promote PA in women with overweight or obesity. Whereas app components will be finalized based on results focus groups and beta testing, an initial list of planned app components includes: a tracking module for PA, mood, and subjective energy, a community message board, educational content (e.g., tenants of body neutrality, benefits of PA beyond aesthetic outcomes, and how to meet PA recommendations), a journaling module, and guided meditations. We will convene an expert advisory board (EAB) who will provide feedback and oversight for the project. We will recruit a nationally representative, racially and ethnically diverse sample of adult women (age 18 and over) with a BMI of ≥ 29.0 kg/m2 for focus groups and beta testing. We will conduct focus groups (4 rounds, n=8 per round for a total n=32) to collect input regarding interest in the app and desired app components. Once 70% of focus group participants express a desire for the app, we will develop clickable wireframes (i.e., interactive prototype of the mobile app). The interactive prototype will be beta tested by n=10 women. We will use a validated scale, the System Usability Scale, to collect quantitative data on prototype usability. The EAB will review focus group input, the quantitative and qualitative data, and feasibility indicators from beta testing to advise the research team on whether programming and evaluating a fully functional app in Phase II research is feasible.