Think Health! A Personal Weight Management Program, or "¡Vive Saludable! Un programa personalizado de control de peso" aims to improve the treatment of obesity in adults in the general population, by conducting research with men and women recruited from primary care medical practices. The study has a particular focus on African Americans and Latino. The design is randomized trial of the effectiveness of two versions of a lifestyle weight loss program called delivered by primary care providers (PCP) and ancillary staff at 5 clinical practice sites to their own patients. The two versions of the lifestyle weight loss program are called Basic (minimal counseling provided by PCP every four months) and Basic Plus (same PCP counseling plus additional counseling by specially trained ancillary practice staff acting as Lifestyle Coaches (LC), monthly for the first 12 months and then every other month for up to 2 years).

Inclusion Criteria:

1. Women and men
2. Ages 18 to 70 years
3. Body mass index > 25 kg/m2 but < 55 kg/m2 or who weigh <400 pounds.

Exclusion Criteria:

1. Pregnancy or lactation, since contraindicated for weight loss or affecting weight status
2. Weight loss > 10 pounds in the previous 3 months
3. Current use of weight loss medications
4. Use of medications known to result in significant weight gain (e.g., oral steroids or second generation anti-psychotics)
5. Psychiatric disorders including untreated major depression, psychosis, bulimia nervosa, and substance abuse
6. Active chemo- or radiation therapy
7. Unstable renal, hepatic, or cardiovascular disease, including malignant arrhythmias
8. Recent (past 3 months) history of myocardial infarction, stroke, or congestive heart failure
9. Participants age < 18 will be excluded because we are only using adult practices and a different type of program would be needed for patients < 18, and age > 70 years will be excluded because our experience has been that a specially tailored program would be needed. As a design consideration, we wanted to decrease the heterogeneity of the program.
10. Participants with a BMI > 55 kg/m2 will be excluded because they are likely to require more extensive medical and behavioral care than can be provided in this study.
11. More than 1 participant residing in the same household will be excluded to avoid contamination across the treatment conditions.
12. Final exclusion criteria will be determined in collaboration with participating primary care providers