The purpose of this study is to describe change in body weight in non-diabetic morbidly obese patients after laparoscopic adjustable gastric banding (LAGB) with twice daily exenatide or placebo injections.

Inclusion Criteria:

1. Age ≥ 18 years,
2. Have a body mass index ≥ 40 kg/m2 or ≥ 35 kg/m2 with comorbidities (1991 NIH Guidelines for Bariatric Surgery),
3. For women of childbearing age, must have a negative pregnancy test at screening, and agree to use barrier contraceptives for the duration of the study, AND
4. Are able to understand and comply with the study process, and give informed consent.

Exclusion Criteria:

1. A diagnosis of type 1 diabetes mellitus,
2. A diagnosis of type 2 diabetes mellitus (A diagnosis of T2DM will be a previous fasting plasma glucose greater than or equal to 126 mg/dL, or a random plasma glucose greater than 200 mg/dL),
3. Have experienced hypersensitivity reaction or a worsening of glycemic control on Byetta® (exenatide),
4. Patients with end stage renal disease or severe renal impairment,
5. Patients with severe gastrointestinal disease, including gastroparesis,
6. Liver function tests 2.5 standard deviations above normal values,
7. Contraindication for bariatric surgery,
8. Treatment with exenatide (Byetta) in the last three months,
9. Currently using or have used within three months before this trial: sibutramine, orlistat, or phentermine(patients must also agree to not use these medications for the duration of the study),
10. Treatment with any investigational drug in the last 30 days,
11. Active malignancy, liver of kidney failure, symptomatic coronary heart disease, or severe psychiatric disease,
12. History of malignancy other than basal cell skin carcinoma, OR
13. In the opinion of the investigator, patient is abusing alcohol and/or drugs.