It may seem strange that something like bariatric surgery could help patients with Type 2 diabetes. After all, it doesn’t involve modifying the pancreas where insulin is produced. But evidence continues to accumulate showing that weight-loss surgery does help patients who have diabetes mellitus or its precursor, insulin resistance. Even patients who don’t currently have diabetes can substantially reduce their risk for developing the disease over time with surgically assisted weight loss.

How Does Weight-Loss Surgery Help Restore Normal Blood Sugar?

There are actually many complex, interrelated functions that determine blood sugar levels. The pancreas has to produce enough insulin to manage glucose in the blood. Then, it has to work efficiently – something that doesn’t happen in insulin resistant patients due to hormones and enzymes that block the action of insulin. Receptor cells in the liver and muscles may also become less responsive to insulin, limiting the body’s ability to break down sugar in the blood stream. The less sensitive the body is to insulin, the more insulin the pancreas must produce to bring blood sugar down to normal levels. The beta cells in the pancreas that produce, store and release insulin can eventually wear out due to being overworked year after year.

Obesity is one well-known factor that increases the risk of hormonal imbalance related to diabetes. Fat in the liver and muscles in particular is associated with poor insulin sensitivity. Overeating (especially simple carbs like sugar) puts stress on the pancreas by forcing it to churn out insulin at high levels.

Bariatric surgery may improve the body’s blood sugar by:

  • Supporting dramatic weight loss over the long term, helping the body produce less of the hormones that can interfere with insulin in the bloodstream
  • Reducing fat content in the liver, improving insulin sensitivity with even relatively minor weight loss
  • Encouraging adherence to a nutritious diet low in simple carbs and high glycemic index foods

Surgeries such as sleeve gastrectomy and gastric bypass that remove part of the stomach also dramatically reduce the body’s ability to produce ghrelin. This is a hormone that causes sensations of hunger, and it is also linked to insulin resistance. The result of a drop in ghrelin hormone is almost instantaneous. It may explain why gastric bypass patients sometimes experience immediate normalization of blood glucose levels after surgery – before they lose any weight at all.

Studies Show Benefits and Limitations of Bariatric Surgery’s Affect on Diabetes

2012 Institute of Medicine in Gothenburg, Sweden

This study followed obese patients for 15 years to track the incidence of diabetes in those who underwent WLS vs. those who did not. The results showed that bariatric surgery is remarkably more effective than traditional med