Biliopancreatic diversion with duodenal switch improves insulin sensitivity and secretion through caloric restriction.

To assess the rapid improvement of insulin sensitivity and β-cell function following biliopancreatic diversion with duodenal switch (BPD-DS) and determine the role played by caloric restriction in these changes. Standard meals were administrated before and on day 3, 4, and 5 after BPD-DS to measure total caloric intake, glucose excursion, insulin sensitivity, and secretion in matched type 2 diabetes and normoglycemic (NG) subjects. In a second set of study, other subjects with type 2 diabetes had the same meal tests prior to and after a 3-day caloric restriction identical to that observed after BPD-DS and then 3 days after actually undergoing BPD-DS. Improvement of HOMA-IR occurred at day 3 after BPD-DS in diabetes and after 3 days of caloric restriction. The disposition index (DI) improved rapidly in diabetes after BPD-DS and to a similar extent after caloric restriction. DI was higher and did not change after BPD-DS in NG. Changes in glucagon-like peptide-1, gastric inhibitory peptide, peptide tyrosine tyrosine, ghrelin, and pancreatic polypeptide levels were not associated with modulation of DI in the participants. Caloric restriction is the major mechanism underlying the early improvement of insulin sensitivity and β-cell function after BPD-DS in type 2 diabetes.