Weight Regain Treatment Post-Bariatric Surgery

Inclusion Criteria: * Be in the age range ≥18 years of age and ≤70 years of age * Have a BMI ≥30 (or BMI ≥27 with a medical comorbidity) and ≤50 kg/m2 * Have had laparoscopic Roux-en-Y gastric bypass or sleeve gastrectomy * Experiencing weight regain after bariatric surgery * Be an otherwise healthy subject without uncontrolled medical problems, as determined by the study physician and medical co-investigators (physical examination, laboratory studies). * Read, comprehend, and write English at a sufficient level to complete study-related materials. * Provide a signed and dated written informed consent prior to study participation. * Be available for participation in the study for up to 3 months. 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 II 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 (since having bariatric surgery). * Is currently in active treatment for eating or weight loss. * 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.