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
