DESCRIPTION: (Adapted from the application) This core will provide the following functions. 1. It will provide trained professionals (behavioral therapists, nutritionists, and exercise physiologists) to implement individual and group-based weight loss programs. 2. Develop new intervention materials, such as lesson plans and self-monitoring tools, and/or tailor intervention materials for specific populations, such as those with lower literacy levels. 3. Help investigators design new interventions for the treatment or prevention of weight-related illnesses, such as for osteoarthritis patients or for post-pregnancy weight reduction. This would include interventions involving cognitive-behavioral approaches, exercise, and/or drugs. 4. Develop and conduct programs to train behavioral psychologists, nutritionists, exercise physiologists, and other professionals to deliver a weight loss intervention. 5. Assist in the management of pharmacotherapy studies and research involving a combination of lifestyle and pharmacologic interventions. 6. Provide facilities in conjunction with the General Clinical Research Center for conducting inpatient studies of the effect of new pharmacologic agents on weigh, body composition, metabolism, and other physiological or behavioral parameters. 7. Develop procedures to determine individual differences in responsiveness to pharmacologic interventions.