10/30/2025
"More than 36 million Americans have type 2 diabetes, a condition primarily attributed to the body’s cells not responding to insulin properly, leading to high blood sugar levels. Due to the concomitant increase in the prevalence of obesity, type 2 diabetes is rising across the U.S. and around the world.
Research shows that most cases of type 2 diabetes can be prevented through lifestyle interventions. But if you already have the condition, can it be reversed?
Gerald I. Shulman, MD, PhD
Gerald I. Shulman, MD, PhD
The answer is a resounding yes, according to Gerald I. Shulman, MD, PhD, George R. Cowgill Professor of Medicine (Endocrinology) and Cellular & Molecular Physiology at Yale School of Medicine (YSM), investigator emeritus of the Howard Hughes Medical Institute, and co-director of the Yale Diabetes Research Center.
Insulin resistance drives type 2 diabetes, Shulman explains. “If you reverse insulin resistance, you reverse type 2 diabetes,” he said. In a landmark study, Shulman and Kitt Petersen, MD, professor of medicine (endocrinology), showed that modest weight reduction—even as little as 10%—does just that. The study, Shulman said, has been replicated multiple times in large groups of individuals.
However, Shulman notes, many people who are initially successful at losing weight regain it. The novel anti-obesity GLP-1 medications can play an important role in helping people maintain this weight loss over the long term to treat diabetes and other diseases, he said.
Patricia Peter, MD, assistant professor of medicine (endocrinology) at YSM, echoes the importance of addressing insulin resistance. “The best way to reverse type 2 diabetes is to decrease your body's resistance to the actions of the insulin made by the pancreas,” she said. “For most people, this means trying to attain a healthy weight, exercising regularly, and minimizing sugars and excessive carbohydrates in your diet.”
Patricia Peter, MD
Patricia Peter, MD
Both Peter and Shulman stress that addressing the disease has significant implications for overall health.
“Over time, high levels of sugar in the blood can damage your vision, nerves, heart, and kidney function,” Peter said. “Thus, the sooner you can get your blood sugars back into the normal range by addressing or reversing diabetes, the less damage that high blood sugar can do.”
Shulman pointed to studies that show a decrease in well-established complications of diabetes, such as blindness, end-stage kidney disease, and non-traumatic loss of limbs, when diabetes is treated.
Even better than treating type 2 diabetes is focusing on what drives it, Shulman added. “In reversing insulin resistance, we not only reverse type 2 diabetes but also prevent heart disease, fatty liver disease, obesity-associated cancers, and Alzheimer’s disease, among many other problems that insulin resistance leads to,” he said."
This article is from the Yale School of Medicine. 02/2025
