The purpose of this study is to test whether a mobile app, the Digital Wellness Nurse (DWN), can help African American families with weight problems lead healthier lifestyles. Participants in this study will receive education and tips on physical activity and healthy eating through weekly videos and online meetings with a community health worker (CHW) via the DWN app. The meetings with the CHW will take place once a week for 12 weeks. During these meetings, adolescents and their caregiver will set weekly goals and have the chance to earn incentives for meeting them. While in the study, participants will be asked to wear a Fitbit to track physical activity and to complete a monthly survey about eating and physical activity habits. At the end of the study, participants will be asked to participate in a focus group and talk about their experiences with the app and the study. Participation in this study may improve physical well-being, but that cannot be guaranteed.