The investigators propose to develop and test the feasibility of Habit, a weight loss mobile app that includes common features such as self-monitoring, goal setting, and a social network, but even more importantly, an avatar-facilitated, idiographic problem solving feature that processes information intelligently to help patients identify solutions to their weight loss problems. In a pilot randomized trial in 50 obese participants, we will test the feasibility of the Habit mobile application when paired with a shortened (8 week) behavioral weight loss intervention relative to a shortened behavioral weight intervention. Feasibility outcomes include frequency and duration of usage of the mobile app and each feature, recruitment, and retention. The investigators will also do exploratory analyses comparing conditions on problem solving skills and weight loss at 8 weeks, which will inform a subsequent randomized controlled efficacy trial. Data will support an efficacy trial of a Habit-assisted brief behavioral weight loss intervention relative to a brief behavioral weight loss intervention alone with 1 year follow-up. The investigators overarching goal is to develop mobile technology that reduces the intensity of lifestyle interventions as far as possible while preserving weight loss outcomes, to ultimately broaden reach.