Process evaluation methods, implementation fidelity results and relationship to physical activity and healthy eating in the Faith, Activity, and Nutrition (FAN) study

• Faith, Activity and Nutrition (FAN) was conducted collaboratively with faith-based partners.
• FAN aimed to improve physical activity (PA) and dietary behaviors in church settings.
• Implementation was not associated with increased PA in mediation analyses.
• Implementing PA messages was associated with self-efficacy for PA.
• Increased PA self-efficacy was associated with increased PA in sequential mediation analysis.

Faith, Activity and Nutrition (FAN), a community-based participatory research project in African American churches, aimed to increase congregant physical activity and healthy eating. The Health-Promoting Church framework, developed collaboratively with faith-based partners, guided the intervention and a comprehensive process evaluation. The Health-Promoting Church components related to healthy eating and physical activity were getting the message out, opportunities, pastor support, and organizational policy. There was no evidence for sequential mediation for any of the healthy eating components. These results illustrate the complexity of systems change within organizational settings and the importance of conducting process evaluation. The FAN intervention resulted in increased implementation for all physical activity and most healthy eating components. Mediation analyses revealed no direct association between implementation and increased physical activity; rather, sequential mediation analysis showed that implementation of physical activity messages was associated with improved self-efficacy at the church level, which was associated with increased physical activity.