A high fat diet inhibits glycosyltransferase= GnT-4a, an enzyme responsible for GLUT 2 function in the pancreas. GnT-4a basically adds a glycan to GLUT 2 in the pancreas to keep this transporter of glucose on the cell surface. If it is inhibited, the GLUT 2 transporter sinks into the cell hence the pancreatic cell can't "see" how much glucose is out there. This leads to reduced insulin output. While a deficiency of insulin can cause diabetes, too much insulin can also be harmful, and has been found to contribute to the pathogenesis of cancer, cardiovascular disease, ovarian diseases, and Alzheimer’s disease. It may be that suppressing insulin production to some degree could be beneficial in such disorders, and that could theoretically be achieved by inhibiting the GnT-4a glycosyltransferase.