Did Study Unlock Secret Why Weight Loss Surgery Reverses Type 2 Diabetes?

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A small amount of fat loss from the pancreas reverses type 2 diabetes for obese patients.

A study just published in Diabetes Care may have uncovered the reason why type 2 diabetes (T2D) disappears in some obese patients who have weight loss surgery.

The connection between gastric bypass surgery and reversal of T2D has been observed for some time, so much so that the procedure may be recommended for patients at a lower body mass index (BMI) if they have disease than for those without. The study from Newcastle University in the United Kingdom finds that it’s all about getting rid of fat in the pancreas. And in these cases, a little goes a long way.

Researchers who studied 18 obese patients both before and after surgery found too much fat in the pancreas prevented insulin secretion and caused type 2 diabetes. And losing just a single gram of fat could be enough for insulin secretion to return to normal levels.


The problem, however, is that significant overall weight loss is needed before the pancreas loses enough fat to make a difference. In this case, patients needed to lose about 13% of their body weight, which drives the loss of 1.2% of fat from their pancreas. This lets patients come off their medication and their insulin levels return to normal.

Roy Taylor, MD, lead researcher on the team, said in a statement from the university, “For people with type 2 diabetes, losing weight allows them to drain excess fat out of the pancreas and allows function to return to normal. So if you ask how much weight you need to lose to make your diabetes go away, the answer is 1 gram! But that gram needs to be fat from the pancreas. At present the only way we have to achieve this by calorie restriction by any means—whether by diet or an operation.”

The team also looked at 9 patients who did not have diabetes before surgery, and the amount of fat in the pancreas remained about the same.

Levels of fat in the pancreas were measured using a highly sensitive MRI. Because the number of patients in this study was extremely small, it’s important for future studies to replicate them, and for follow-up work to find out if T2D remains at bay as long as high fat levels do not return in the pancreas.


Steven S, Hollingsworth KG, Small PK, et al. Weight loss decreases excess pancreatic triacylglyceral specifically in type 2 diabetes [published online December 1, 2015]. Diabetes Care. 2015; doi: 10.2337/dc15-0750.