Weight loss surgery may provide a new treatment for obese people with Type 2 diabetes, as a new three-year study has shown promising results.

According to USA Today, one-third of the 150 study participants were treated for their diabetes with medication and lifestyle changes. One-third had gastric bypass surgery and the last third had a type of bariatric surgery called a sleeve gastrectomy.

All participants ranged from overweight to mildly obese and had diabetes uncontrollable by medication. Type 2 diabetes is the most common and is often linked to obesity.

Study co-author Philip Schauer said the difference between the surgery participants' and the medical participants' blood sugar levels at the end of the study was noticeable.

"At three years, the therapeutic gap - the difference between blood sugar in the surgical group and the medical group - got even larger in favor of surgery," Schauer, a surgeon and director of the Cleveland Clinic's Bariatric and Metabolic Institute told USA Today.

The researchers have not yet been able to explain why the surgery was so successful and why patients began seeing improvements right away. Within only a few days after surgery, patients who used insulin the morning before surgery no longer needed their medication. By the end of the study, the surgery patients' blood sugar levels were practically normal.

"People who had surgery were able to feel less body pain, they were more functional, they had a better quality of life, and their general health was better," study lead author Dr. Sangeeta Kashyap, an endocrinologist at the Cleveland Clinic, told NBC News. "People were happier and healthier as a result of having the bariatric surgery."

Kashyap and the study researchers presented their findings the American College of Cardiology meeting in Washington D.C. The study is published in the New England Journal of Medicine.

"Initially we thought diabetes was a disease you could not reverse or end," said Kashyap, according to Reuters. "We do realize now that there may be a treatment that could end diabetes for some people and that's exciting."