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Gastric Bypass Surgery:

A Cure for Type II Diabetes?

Dana Ferguson

October 8, 2009

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Type 2 diabetes is a condition in which the body becomes resistant to insulin, a hormone that metabolizes glucose into energy. Although type 2 diabetes accounts for 90 to 95% of all cases of diabetes, (Engelgau et al., 2004) its exact cause is still unknown. Many doctors attribute the disease to excessive weight or obesity, citing that a surplus of fat cells in the body inhibits the proper use of insulin, and that the pancreas cannot make enough insulin to overcome this resistance. However, this theory does not explain the 20% of type 2 diabetics who are not overweight ( What could be the cause of type 2 diabetes in these individuals if it is not weight? Clearly, there is some other factor that contributes to the development of the disease, and new research in bariatric surgery, particularly gastric bypass surgery may have just the answer.

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Gastric Bypass as a Cure for Type 2 Diabetes?

Gastric bypass surgery, the most common form of bariatric surgery, has been found to effectively eliminate type 2 diabetes in its patients. Yet, new research suggests that the remission of diabetes is not simply because of the weight lost post-surgery. It may, in fact, be because of the surgery itself. In a composite study of 60 diabetic patients, 80% of those who had gastric bypass surgery experienced complete remission of their diabetes soon after their operation, some even within days ( Because diabetes in bypass patients seems to disappear long before any significant amount of weight is lost, several doctors and scientists are starting to believe that diabetes remission may be independent from the weight loss associated with gastric bypass surgery. Furthermore, if surgery really is the primary reason for diabetes amelioration in overweight patients, could it have the same effect on diabetics of normal weight? Likewise, if such a comprehensive treatment exists, what implications would it have on the way diabetes is conceptualized and treated in the future?


Finding the Origin Means Finding a Cure?

        In 2004, Dr, Rubino of New York Presbyterian Weill/Cornell Medical Center sought to answer these questions. In a series of clinical studies, Dr. Francesco Rubino performed gastric bypass on diabetic rats (of normal weight) and made a critical discovery. By disconnecting the top area of the small intestine, an area known as the duodenum, Rubino’s rats were cured of their diabetes within days after their surgery. Conversely, reversing the operation and reattaching the duodenum caused their diabetes to return completely ( From these observations, Rubino concluded that the development of type 2 diabetes is most likely due to abnormalities produced in the upper intestine. Hence, the resolution of type 2 diabetes following gastric bypass surgery is more likely due to the reconfiguration of the intestinal tract, and not resultant caloric restriction and weight loss, as most medical experts assume. As Dr. Rubino wrote in the Annals of Surgery, "The effect on glucose metabolism seems to be a direct consequence of the duodenal exclusion (the area of the intestine bypassed) rather than secondary to weight loss," (Rubino and Marescaux, 2004, p. 391).

        In yet another experiment led by Dr. Rubino, researchers studied whether weight loss from gastric bypass surgery had any more of an effect on diabetes than weight loss from diet and exercise alone. The researchers performed standard gastric bypasses on one group of obese diabetic mice, while they monitored the diet of a non-surgical control group of equivalent subjects. As the experimental group began losing weight post-surgery, the researchers restricted the food given to the control group so that both groups were losing equal amounts of weight at the same speed. In this way, the weight loss for both groups was virtually the same, but the state of their diabetes was not. The researchers found that weight loss from the bariatric operation had a much more profound effect on diabetes than weight loss from diet and exercise alone. (Rubino and Marescaux, 2004)

                But why?

Bariatric surgeon, Dr. Louis Flanbaum of New York’s St. Luke’s-Roosevelt Hospital, offers this explanation: "…the re-routing of food [after surgery] alters the way hormones are secreted from the foregut and from the pancreas.” ( Bypassing the upper gut leads to an elevation of the pro-insulinogenic hormones that regulate glucose levels in the body, and a subsequent remission of diabetes. This supports Rubino’s claim that the diabetic benefits of gastric bypass surgery are independent of weight loss. Consequently, this data also identifies the mechanisms in the bypassed intestine as the source of diabetes development.  


How Effective Could a Surgical Cure Be? What Does the Data Show?

        The idea of gastric bypass surgery as a plausible cure for type 2 diabetes is very new, and there is limited published data on the subject, other than Rubino’s studies. Yet, in order for the theory of intestinal diabetic causation to be more readily received by the scientific community, more research must be done. At this point in time, most doctors still subscribe to the conventional idea that the cause of diabetes isn’t intestinal malfunction, but rather complications from the surrounding fat. Surgically induced weight loss and decreases in fat and caloric intake are still the most preferred explanation for bariatric surgery’s effect on diabetes. In other words, losing weight is still seen as the primary reason for diabetes remission in bypass patients. Despite conflicting theories, experts agree that more studies must be conducted before making any concrete conclusions about the benefits of gastric bypass surgery for all type 2 diabetes patients, regardless of weight.


The Future of the Gastric Bypass Fix  

        Dr. Rubino’s seemingly controversial findings offer compelling proof that we are on the threshold of potentially curing type 2 diabetes. The current data reveals that gastric bypass surgery has a greater positive effect on the treatment of type 2 diabetes than weight loss alone. Rubino is hopeful that these findings will eventually lead to the treatment of type 2 diabetes patients of all sizes, though currently, only diabetics who are markedly obese (with a body mass index of 35 or greater) are eligible for the bariatric surgery. Since 2004, Dr. Rubino has begun conducting clinical human trials for non-obese type 2 diabetics. He and other medical professionals are excited about these promising trials, and are very optimistic about the future of gastric bypass surgery as an effective treatment for type 2 diabetes.






























Carmichael, M. (2008, August 25). Is there a surgical cure for diabetes?. Retrieved October

1, 2009, from


Dakss, B. (2005, November 5). Type 2 diabetes: Surprising cure. Retrieved October 1, 2009,


Engelgau, M. M., Geiss, L. S., Saaddline, J. B., Boyle, J. P., Benjamin, S. M., Gregg, E. W., Tierney,

E. F., … Narayan, V. (2004). The Evolving Diabetes Burden in the United States.

Annals of Internal Medicine, 140(11), 945-950.

Retrieved from


Liu, W., & Zassoko, R. (2008) Establishment of Duodenojejunal Bypass Surgery in Mice: A

Model Designed for Diabetic Research. Microsurgery, 28(3), 197-202


Rubino, F., & Marescaux, J. (2004) Effect of Duodenal-Jejunal Exclusion in a Non-Obese

Animal Model of Type 2 Diabetes: A New Perspective for an Old Disease. Annals of

Surgery, 240(2), 389-391


Bariatric surgery in India will cure diabetes disorder. (n.d.). Retrieved October 2, 2009,



The bypass effect on diabetes, cancer. (n.d.). Retrieved October 1, 2009, from






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