Research suggests that when one spouse loses weight, the other spouse does too. This study will examine whether a ripple effect is observed in untreated spouses and children of individuals participating in a nationally available weight loss program. Participants will be randomly assigned to either receive Weight Watchers immediately or at the end of a 6-month waiting period. Participants and untreated spouses (and any children in the home) will be assessed at baseline, 3, and 6 months.

Inclusion Criteria:

• body mass index between 27.0-40.0 kg/m2
• married or living with a significant other who had a BMI > 25 kg/m2

Exclusion Criteria:

• currently in a weight loss program, dieting, or taking medications that might affect weight
• had participated in a weight loss program in the past year
• lost > 5% of their body weight in the past 6 months
• were planning to or had undergone weight loss surgery
• had any orthopedic limitations or contraindications to physical activity
• were pregnant, lactating, or less than 6 months postpartum, or were planning to become pregnant in the next year
• reported uncontrolled hypertension, history of coronary heart disease, stroke, or peripheral arterial disease; reported chronic gastrointestinal disease
• endorsed having hepatitis B or C, cirrhosis, or HIV
• had a history of cancer within the past 5 years
• reported a significant psychiatric illness that might interfere with completion of the study.