The main goal is to study the effect of meal size and texture on incretin levels after GBP. Patients will be studied before GBP (T0) and 12-15 months after GBP (T1). At T0 and T1, patients will come for 2 study days for 8 hours: On one study day, a single meal will be served, on the second study day, three small meals, with the order of the conditions randomly assigned. The total amount of calories (600 kcal) and the over all nutrient composition (55% CHO, 15 % protein, 30% fat) will be equivalent between conditions. The meals will be either all solid or all liquid. Patients enrolled in the study will be randomly assigned to solid or liquid test meals.
Recruitment and data gathering for this study were performed at St. Luke's Hospital in New York, NY. Data Analysis was performed at Columbia University Medical Center in New York, NY.