Optimizing an Extended Care Intervention to Promote Weight Loss Maintenance

The purpose of this study is to find out what combination of components, if any, offers the best support for keeping weight off after someone loses weight. Long term weight loss maintenance is a challenge for many people who lose weight. There are many strategies, or components, people may use to avoid regain, but investigators do not know if there is a best, or optimal, combination of such components that can be done without adding a lot of cost or other burdens for people.

* The primary goal of this clinical trial is to identify the optimal package that maximizes weight loss maintenance.
* The study also wants to understand the reasons why these components may work and if certain components help specific sub-groups of people.

Participants will engage in a 16-week Phase 1 Weight Loss Program. Participants who lose 5% or more of their weight during that program will continue to Phase 2 Extended Care and be randomly assigned to 0, 1, 2, 3, or all of four methods of weight loss maintenance. They will use their assigned package for 12 months. Researchers will compare 16 different possible combinations of components and learn which of the 16 packages offers the best support for keeping weight off.

The four components participants could be assigned to in Phase 2 are:

1. Reduced Food Variety: Limiting the variety of foods participants eat by having them choose a few high-calorie, low nutrient foods to eat regularly
2. Home-based Resistance Training: Engaging in exercises that build strength from the comfort of the participant's own home
3. Buddy Training and Support: Having a friend or "buddy" get trained to support the participant
4. Acceptance and Commitment (ACT) Workshops: Having participants learn skills to handle tough thoughts and feelings about weight control in a healthy way

Participants will have their weight measured and complete surveys 4 times if they complete both Phase 1 and Phase 2. During Phase 1, participants will attend weekly group sessions and be in touch with a study staff member investigators call a Wellness Coach. During Phase 2, participants will stay in touch with their Wellness Coach, use their assigned package, and answer questions about their experience periodically.


Eligibility Criteria:
Inclusion Criteria:

* Age \>18 years
* Body mass index (BMI) \>30 kg/m2
* Has regular access to internet (to access Zoom videoconferencing platform)
* If indicated during screening, willing to obtain medical clearance for exercise from their healthcare provider prior to enrollment

Exclusion Criteria:

* Current or recent (past 6 months) use of prescription weight loss medications
* Weight loss \>10 pounds in past 6 months (other than postpartum)
* Pregnancy or anticipating pregnancy
* Another household member already participating in the study
* Participation in another randomized research project
* Uncontrolled hypertension (blood pressure \>160/100 mm Hg at screening)
* Any of the following other medical conditions: myocardial infarction or cerebrovascular accident within the last 6 months; unstable angina within the past 6 months; NYHA Class III or IV congestive heart failure; type 1 diabetes; and chronic lung diseases that limit physical activity
* Unable to identify potential buddy (i.e., adult friend or family member) for extended care intervention phase
* Residing \>50 miles from the university (to attend assessment visits)
* Planning to relocate out of the area in the next 18 months
* Does not have internet access
* Unwilling or unable to do any of the following: give informed consent; read/understand English; accept random assignment