The primary aim of the study is to investigate whether GLP-1 released as a result of increased carbohydrate content in the distal and L cell-rich part of the small intestine after a meal affects postprandial plasma glucose levels in patients with type 2 diabetes. This will be done by applying an alpha-glucosidase inhibitor (to increase the postprandial carbohydrate content in the distal small intestine) and the specific GLP-1 receptor antagonist exendin(9-39) (to isolate any GLP-1-mediated effects) during meal tests in patients with type 2 diabetes.