An app-based lifestyle program designed for the research study ‘Stay Strong for Operation Enduring Freedom/Operation Iraqi Freedom/ Operation New Dawn (OEF/OIF/OND) Veterans’. The app is to be used to help participating OEF/OIF/OND Veterans increase their physical activity levels which may help prevent future health problems. The app will collect information via Fitbit API and a Bluetooth scale. Participants who are randomized to the Stay Strong with Coach group will receive personalized physical activity goals each week as well as tips and tailored messages to help participants reach their weekly physical activity goal. Synced activity and weight data will be available in a dashboard within the app for all users. This app is part of a year-long research project sponsored by Veterans Affairs, Health Services Research & Development. Full access to the app will only be provided to eligible Veterans who enroll in the voluntary research study