Obesity risk is shared within married couples yet most existing weight loss programs focus on individuals and not the marital dyad. This project will test the effects of a couples weight loss program that teaches spouses how to provide each other with autonomy support and create an interpersonal environment that promotes sustained behavior change.

Inclusion Criteria:

18-70 years old interested in receiving free weight loss treatment with their spouse have a body mass index (BMI) between 25 and 45 kg/m2. Individuals who respond to the advertisement will be screened for eligibility by phone. Eligibility will be limited to married/cohabitating couples (n=64) in which each spouse is 18-70 years old with a BMI between 25-45 kg/m2.

Exclusion Criteria:

currently in a weight loss program, dieting, or taking medications that might affect weight participated in a weight loss program in the past year have lost > 10% of body weight during past 6 months are currently participating in any other research study that may interfere with this study are pregnant, lactating, < 6 months postpartum, or plan to become pregnant during the study have undergone cancer treatment within the past year, not including skin cancer treatment have substance abuse, dependence, average more than 14 drinks per week, or are currently being treated for alcohol or substance abuse have a heart condition, chest pain during periods of activity or rest, or loss of consciousness report uncontrolled hypertension, history of coronary heart disease, stroke, peripheral arterial disease or have a blood pressure ≥160/100 mmHG as measured by study staff at baseline report chronic gastrointestinal disease endorse having hepatitis B or C, cirrhosis, or HIV; or report a significant psychiatric illness that may interfere with completion of the study deemed by study staff to be unlikely to adhere to study protocol (e.g. moving in the next 12 months).