Studies have shown that being overweight is a major risk factor for developing type 2 diabetes: roughly 30 percent of overweight people have diabetes, and 85 percent of people with diabetes are overweight.1 Looking at these numbers, your first question might be: how do we lower our risk of diabetes? The first strategy is weight loss – and this is where bariatric surgery can come into play in the treatment, and even resolution, of type 2 diabetes.

Key takeaways
- Patients typically lose about 25% of their weight after bariatric surgery, improving glucose control and insulin resistance.
- 87% of patients with type 2 diabetes achieve better glucose control with fewer medications; on average 78% achieve normal glycaemic control without medication.
- Gastric bypass leads to remission in more patients (82–99%) than gastric sleeve surgery.
How can bariatric surgery resolve, manage or treat type 2 diabetes?
The quick answer is weight loss. After bariatric surgery, patients lose more weight, faster, than with traditional methods – typically about 25% of their weight. This weight loss helps achieve better glucose control and decreases insulin resistance. Among patients with type 2 diabetes, 87% achieve at least better glucose control and need fewer antidiabetic medications, and an average of 78% achieve normal glycaemic control without taking any antidiabetic medications.2
Not all procedures have the same effect
Not all bariatric procedures have the same effect on weight and diabetes. Here are two types of procedure and their effect on diabetes:
| Gastric sleeve | Roux-en-Y gastric bypass | |
|---|---|---|
| How it works | Limits gastric volume, limiting calorie intake by speeding up satiety | Restricts calorie intake and, because the small intestine is shortened, adds malabsorption of fat and nutrients |
| Weight loss | About 10–20% of body weight2 | – |
| Diabetes | Weight loss improves insulin sensitivity several months after surgery | Remission of type 2 diabetes in 82–99%, even with longer disease duration, including patients treated with insulin2 |
| Best suited to | A newer diagnosis of diabetes (< 5 years) that is relatively well controlled | People with diabetes on insulin looking to achieve remission or, at the very least, better control |
Gastric sleeve surgery is currently the most common bariatric procedure. It limits gastric volume, limiting calorie intake by increasing the speed of satiety. Patients lose about 10–20% of their weight,2 which helps improve insulin sensitivity several months after surgery. Gastric sleeve surgery is best for a patient with a newer diagnosis of diabetes (less than 5 years) whose diabetes is relatively well controlled.
Like gastric sleeve surgery, Roux-en-Y gastric bypass restricts calorie intake and induces weight loss. But because the small intestine is shortened, patients also experience malabsorption of fat and nutrients. This helps more patients achieve remission of type 2 diabetes (82–99%) than after gastric sleeve surgery – even patients with a longer duration of disease, including those treated with insulin.2 This makes gastric bypass the preferred surgery for people with diabetes on insulin who want to achieve remission or, at the very least, better control of their diabetes.
In summary
Any bariatric surgery can have a positive effect on managing and improving your diabetes. If you are on insulin or have had diabetes for a long time and want a higher chance of remission, you should choose gastric bypass surgery, as this will give you the best results!
The choice of procedure is always made together with your bariatric surgeon, based on your medical history.
Sources
- Powell A. Obesity? Diabetes? We've been set up. Harvard Gazette. https://news.harvard.edu/gazette/story/2012/03/the-big-setup
- Kashyap SR, et al. Bariatric surgery for type 2 diabetes: weighing the impact for obese patients. Cleveland Clinic Journal of Medicine. July 2010. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3102524/
This article is for general information only and does not replace personal medical advice. Always discuss your situation, blood test results and supplementation with your bariatric team or healthcare provider.