Optimizing Self-Monitoring Feedback Delivery for the Treatment of Overweight and Obesity

The goal of this micro-randomized factorial trial is to learn how to best deliver self-monitoring feedback during a behavioral weight management intervention. All study participants will be provided with a "Weight Loss 101" session that provides weight loss education and behavioral skills training. At this meeting, participants will be taught how to use study-provided tools to self-monitor their dietary intake, physical activity, and weight. At the end of each week of the intervention, participants will receive an interventionist-composed feedback message based on their self-monitoring data. Every message will contain feedback about how often the participant self-monitored their dietary intake, physical activity, and weight (that is, the number of days each week that the participant monitored each) along with a message about their weight trajectory. Participants will be randomized each week to receive (or not receive) four additional feedback components each week. The main questions that this study aims to answer are: * which of the four additional feedback components improve adherence to self-monitoring, intervention goals, and weight loss the week after they are received? * are there any differences in message impact depending on the person receiving the message (for example, do some messages work better for younger versus older participants) or their context (for example, are certain messages more or less helpful depending on how well the person is doing in the program)?