Gut Hormones and Roux en Y Gastric Bypass

This study is examining how gut hormones (the chemical messengers produced in your digestive system) change after a type of weight-loss surgery called Roux-en-Y gastric bypass, to better understand why this surgery helps control blood sugar in people with type 2 diabetes. **You may be eligible if...** - You are scheduled for or have recently had Roux-en-Y gastric bypass surgery - You have been diagnosed with obesity (body mass index above a certain level) - You may or may not have type 2 diabetes - You are between 18 and 65 years old - You are willing to attend study visits and provide blood samples at multiple time points **You may NOT be eligible if...** - You have had prior stomach or intestinal surgery (other than the gastric bypass being studied) - You have serious kidney, liver, or heart disease - You are pregnant or planning to become pregnant during the study - You are using certain medications that affect blood sugar or gut hormones - You have type 1 diabetes Talk to your doctor to see if this trial is right for you.