The goal of this clinical trial is to learn if a group-based digital weight loss program that is delivered asynchronously (via an online platform) is as effective as one that is delivered synchronously (via weekly videoconference meetings). In the asynchronous condition, participants can engage with their group any time 24/7. In the synchronous condition, participants can engage with their group once a week at a videoconference meeting. The main questions it aims to answer are: Will participants in each condition lose about the same amount of weight? Will the participants in the asynchronous condition participate more than those in the synchronous condition? Will the participants in the asynchronous condition feel more connected to each other than those in the synchronous condition? Will the asynchronous condition cost less to deliver per pound lost than the synchronous condition? Participants will: Receive a digital weight loss program that lasts 1 year and then volunteer participants will be selected to lead the group for 1 year following the program, a phase called the peer-led weight loss maintenance phase. Complete study assessments at baseline, 6, 12, 18, and 24 months.