About 20 million Americans currently have type 2 diabetes, three times more than in 1980. Diabetes is a major risk factor for stroke and heart attack, is the leading cause of new cases of blindness, and is the largest cause of the need for dialysis. Diabetes is also usually progressive, meaning that on the same medications and on the same diet and exercise regimen, the blood sugar of a patient with diabetes will slowly increase, necessitating constantly increasing amounts of medications. So des...