In general, we do not consider that diabetes can be cured once it has been diagnosed.
People with type 2 diabetes can reverse the detectable abnormalities of diabetes by lifestyle adjustment without the use of medications. However, the tendency to manifest high blood sugar again is always present if the patient is under significant metabolic stress, such as that caused by medications, severe illness, injury, regaining lost weight, cessation of exercise, aging, etc. Therefore we consider that diabetes can be under excellent control or in remission, but we do not usually use the word cured. Even people with type 1 diabetes who have undergone successful pancreas or islet transplantation and no longer require insulin therapy cannot be considered cured. There is a significant possibility that their diabetes will one day come back for a variety of reasons, including rejection of the transplant or a renewed attack on the transplanted islet tissue by the patient’s immune system.
Perhaps the closest we have been able to come in the search for a true cure for diabetes is the effect of bariatric surgery (“weight loss surgery”), which either involves procedures to restrict the entry of food into the stomach or procedures to bypass the stomach and upper intestine, thus reducing food absorption. Procedures of the bypass type have shown prolonged remission of diabetes in up to 80% of cases for as long as 10 years. Remission for 10 years or more is approaching a definition of a true cure, and in the future this and other medications or procedures that provide a long-term reversal of obesity may come to be generally accepted as “curing” type 2 diabetes.
Reference: Research by American Diabetes Association