About one-third of diabetics are believed to be undiagnosed. Type 2, or adult onset, accounts for about 90 percent of diabetes cases. About 80 percent of people with type 2 diabetes are overweight. Diabetes results from a lack of insulin or a lack of response to insulin by the body or both. After a meal, the hormone insulin prompts muscle and fat cells to take up glucose from the blood.
Muscle takes up most of the body's glucose after a meal.
Insulin also turns off glucose production by the liver. When type 2 diabetes is diagnosed, the pancreas is usually producing increased insulin, but the body cannot respond to the insulin effectively, a condition called insulin resistance. Pancreatic beta cells respond by making extra insulin, but eventually the insulin is inadequate to overcome the insulin resistance. When glucose cannot get into the cells that need it, the sugar builds up in the blood. Normally, insulin triggers muscle and fat to send GLUT4 to cell membranes to transport glucose into the cells, where it is converted into complex carbohydrates and fat.