This study will compare the effectiveness of behavioral and pharmacologic treatment, alone and combined, for improvements in weight loss, cardiovascular risk factors, and psychosocial functioning following metabolic and bariatric surgery.

Metabolic and bariatric surgery is currently the most effective treatment for severe obesity; however, a substantial proportion of patients attain suboptimal weight losses and continue to struggle with obesity, weight regain, and related medical comorbidities after surgery. Thus, this study aims to perform a randomized double-blind placebo-controlled study to test the effectiveness of a rigorous manualized behavioral weight loss treatment and a FDA-approved weight loss agent (naltrexone+bupropion), alone and in combination, for improving weight loss, cardiovascular risk factors, and psychosocial functioning after metabolic and bariatric surgery. This study will produce important new clinical findings regarding the utility and effectiveness of pharmacotherapy and behavioral weight loss for a rapidly growing obesity subgroup and will inform care models for managing chronic and refractory obesity to enhance outcomes after metabolic and bariatric surgery.

Inclusion Criteria:

• Provision of signed and dated informed consent form
• Stated willingness to comply with all study procedures and availability for the duration of the study (up to 18 months: 6-month treatment plus 12-month follow up)
• Have a BMI ≥30 (or BMI ≥27 with a medical comorbidity) and BMI ≤50 kg/m2
• Have had laparoscopic Roux-en-Y gastric bypass or sleeve gastrectomy
• Suboptimal weight outcomes after MBS
• Be an otherwise healthy subject without uncontrolled medical problems, as determined by the study physician and medical co-investigators (physical examination, laboratory studies).
• Have had a physical in the past year
• Read, comprehend, and write English at a sufficient level to complete study-related materials.
• For females of reproductive potential: use of highly effective contraception and agreement to use such a method during study participation
• For males of reproductive potential: use of condoms or other methods to ensure effective contraception with partner

Exclusion Criteria:

• Has a predisposition to seizures (e.g., subject with a history or evidence of seizure disorder, febrile seizures during childhood, brain tumor, cerebrovascular disease, or significant head trauma; has a family history of idiopathic seizure disorder or is currently being treated with medications or treatment regimens that lower seizure threshold).
• Has a history of anorexia nervosa or history of bulimia nervosa.
• Is currently taking a medication that is a contraindication to NB medication (e.g., MAOI, opiates).
• Is currently using other medications for weight loss.
• Has a history of allergy or sensitivity to bupropion or naltrexone.
• Has a co-existing psychiatric condition that requires hospitalization or more intensive treatment (such as bipolar mood disorders, psychotic illnesses, or severe depression)
• Has untreated hypertension with a seated systolic blood pressure > 160 mmHg, diastolic blood pressure > 100 mmHg, or heart rate > 100 beats/minute.
• Has a history of congenital heart disease, cardiovascular disease, cardiac arrhythmias requiring medication, or a history of cerebrovascular pathology including stroke.
• Has current uncontrolled hypertension.
• Has current uncontrolled Type I or Type 2 diabetes mellitus.
• Has untreated hypothyroidism with a TSH > 1.5 times the upper limit of normal for the test laboratory with repeat value that also exceeds this limit.
• Has gallbladder disease.
• Has a history of severe renal, hepatic, neurological, chronic pulmonary disease, or any other unstable medical disorder.
• Has a recent history of drug or alcohol dependence.
• Is currently in active effective treatment for eating or weight loss such as behavioral weight loss of FDA-approved weight loss medications.
• Is currently participating in another clinical study in which the subject is or will be exposed to an investigational or a non-investigational drug or device.
• Is breast-feeding or is pregnant or is not using a reliable form of birth control.
• Reports active suicidal or homicidal ideation.
• Has poor eye health