The study is being undertaken to understand how the Roux-en-Y Gastric Bypass procedure can affect insulin secretion after meals. The hypothesis of this study is the Disposition Index is decreased in subjects who had previously undergone Roux-en-Y Gastric Bypass by glucagon-like peptide-1 (GLP-1) receptor blockade.

Inclusion Criteria Roux-en-Y Gastric Bypass (RYGB)Subjects:

• Subjects who have undergone RYGB

Inclusion Criteria Healthy Subjects:

• Must match RYGB subjects in age, weight, and gender
• Subjects will be without active systemic illness

Exclusion Criteria all Subjects:

• Subjects <20 years old and >70 years old
• For Female Subjects: positive pregnancy text at the time of enrollment or study
• Subjects with functional or organic bowel symptoms.