Why Can Losing Weight Reverse Type 2 Diabetes? Scientists Offer New Answer

Losing weight was shown to reverse Type 2 diabetes in participants in a British study. Getty Images

Growing evidence suggests losing weight can reverse Type 2 diabetes in some people, and a new study has shed light on why this could be.

Shedding the pounds appears to help restart specific cells in the pancreas, the organ whose function is affected by the condition.

More than 100 million adults in the U.S. have diabetes or prediabetes, according to the Centers for Disease Control and Prevention. Worldwide, 90 percent of the 422 million people diagnosed with diabetes have Type 2.

The research, carried out at Britain's Newcastle University, homed in on beta cells, which are unique to the pancreas and produce, store and release the hormone insulin. It followed existing work by the same institution that suggested substantial weight loss around the time of diagnosis could revive these cells, professor Roy Taylor, the study's senior author and a diabetes expert at Newcastle, told Newsweek.

In the previous study at Newcastle, 280 people diagnosed with the disease were split into two groups. They were randomly assigned to a weight loss program, where they stopped taking diabetes medication and ate soups or shakes totaling no more than 853 calories a day for five months, or continued with their usual care. After a year, 46 percent of participants in the diet group had lost weight and regained control over their blood glucose levels.

The team then continued their study on 41 of the original participants, 29 of whom were put in remission and 16 who were not. Using a specially developed MRI scan, the researchers measured the fat levels in the liver and pancreas and studied the beta cells.

Taylor explained, "Liver fat levels were surprisingly high in people with unremarkable Type 2 diabetes—they did not know they had any liver problem. Removal of fat from the pancreas was followed by insulin-producing cells returning to normal only in those people who became diabetes-free. People who were unable to restart normal insulin production had been diabetic for a longer time."

The study, published in the journal Cell Metabolism, also showed those who didn't reverse their diabetes had lived with it for, on average, 3.8 years, compared with 2.7 years for those who got rid of the disease.

The findings hit back at previous research suggesting Type 2 diabetes irreparably damages beta cells, said Taylor, as the condition has long been regarded as lifelong and progressive, with half of patients needing insulin injections within a decade.

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"This adds up to a major change in how Type 2 diabetes should be viewed," he said. "It is a potentially reversible condition, and commencing successful major weight loss should be started as early as possible. It also simplifies understanding of Type 2 diabetes. It is simply due to too much fat inside the liver and pancreas of people who happen to be susceptible to the fat-induced damage."

However, Taylor acknowledged that participants had to lose more than 22 pounds, on average, to reverse the Type 2 diabetes. "Not everyone with diabetes would wish to make the large changes necessary to return to normal health," he said.

"If you have a family history of diabetes, then it would be wise to avoid any weight gain in adult life," he continued. "If you are heavier than you were in your mid-20s, get back to that weight."