This study evaluates how ectopic fat (in the pancreas, heart, liver and skeletal muscle), visceral fat, and subcutaneous fat changes following surgically induced weight loss using gastric banding. The investigators also evaluate whether changes in pancreatic fat content correlate with improvement in beta-cell function.

We are looking for volunteers for this study,wich involves 7 visits over a period of 13 months, the first visit taking place about 2 weeks prior to the planned surgery.

Visit 1 - baseline, before starting your pre-operative diet Visit 2 - just before the surgery Visit 3 - around the time your first band inflation occurs Visit 4 - 1 month after the band inflation Visit 5 - 3 months after the first band inflation Visit 6 - 6 months after the first band inflation Visit 7 - 12 months after the first band inflation

At each visit we do the following tests:

1. MRS to measure your fat in the liver, pancreas, heart, muscle (leg), subcutaneous fat and visceral fat.
2. Frequently sampled intravenous glucose tolerance test - it is a 3.5 hrs test which determines the amount of insulin your body produces and how well your own insulin is being used by the body
3. Body measurements (waist, hip circumference), cholesterol panel, liver function tests, HbA1c (to monitor diabetes control), blood pressure, weight.

We also do an oral glucose tolerance test to check for diabetes on 3 occasions: visit 1, visit 5 and at the end, visit 7.

Inclusion Criteria:

• Greater than 18 years old
• Fully understanding and willing to undergo study procedures
• Available for follow-up
• Understand and willing to sign informed consent
• Pharmacologic agents with the potential to change ectopic fat content (i.e. pioglitazone) are allowed if the patient has been on a stable dose for at least 3 months and plans to continue the same dose for the duration of the study

Exclusion Criteria:

• Contraindication to MRI (i.e. metallic implants, severe claustrophobia, weight above 320lb)
• Contraindication to phlebotomy (i.e. no accessible veins, hemoglobin <10 mg/dL)
• History of pancreatic disease other than diabetes
• Regular use of more than 2 alcoholic drinks per day
• Pregnancy
• Non-English speaking

Patients already scheduled to undergo gastric banding within 1-2 months.

This study does NOT pay for the bariatric surgery, eligible participants must already be scheduled to have the surgery performed by their own physician

13 months