This trial will test the effectiveness of a weight loss maintenance intervention designed to help participants respond more adaptively to weight regain. Participants will be randomly assigned to one of two conditions. In one condition, participants will receive brief exercises (e.g., written reflections, videos) sent to through a smartphone app immediately after they regain weight or miss a weigh-in. These exercises will use mindfulness, acceptance, and self-compassion strategies to help participants stay motivated for their long term goals, even when weight regain feels demoralizing. In the comparison condition, participants will receive weekly reminders of standard weight control strategies strategies.