Reducing Obesity Using Social Ties Program

This trial aims to test the feasibility and acceptability of addressing interpersonal barriers to weight-related behavior change. Specifically, the study will test if, by including up to two friends, family members, or co-workers in a lifestyle intervention for weight loss, the person enrolled in the study loses more weight than someone whose friends, family members, or co-workers were not invited to participate.

The investigators will evaluate whether the ROBUST intervention not only addresses individual-level behaviors (i.e., healthy eating, increased physical activity) but also: 1. reduces social undermining as well as changes perceived health norms by activating communal coping - a behavioral process that involves thinking, communicating, and acting as if a health risk (i.e., Type 2 diabetes) is shared; and 2. dampens the harmful effects of increased interpersonal conflict on weight by teaching participants how to induce a positive affect and self-affirming mindset Participants in the control arm will receive the same number of lifestyle sessions as those randomized to the social network intervention. Participants will: 1. Be randomly assigned to either the study group, which is asked to invite up to two friends or family members to join them at three coaching sessions, or the group that does not invite anyone. 2. Receive 15 coaching sessions over 24 weeks. 3. Complete an online questionnaire about eating and physical activity habits, confidence in developing healthier habits, mood, and health habits of twelve of their closest friends and family members. 4. Complete a 3-day weekly food log and wear a provided Fitbit for at least 9 hours daily. 5. The invited friends and family members will also be asked to complete a brief questionnaire about their eating and physical activity habits when they start and end the study.