You don’t have to lose weight to lower your diabetes risk, scientists say

Prediabetes affects millions of people across the globe. About one in ten adults is estimated to have the condition, though the true number is likely much higher due to undiagnosed cases. Prediabetes occurs when blood sugar levels rise above normal but are not yet high enough to be classified as diabetes. It often develops silently, showing no symptoms at first. As the body's cells become resistant to insulin, less sugar moves from the bloodstream into the cells, causing blood sugar levels to climb. If untreated, prediabetes can progress to type 2 diabetes, which currently impacts more than 460 million people worldwide and increases the risk of serious complications such as heart disease and certain cancers.

Normal Blood Sugar as a Key Goal

Up to now, most diabetes prevention programs and clinical guidelines have centered on weight loss through healthy eating and regular physical activity. The new findings suggest this approach could be expanded beyond focusing solely on body weight.

Researchers at the University Hospital Tübingen followed more than 1,100 participants in a long-term study. Among them, 234 people either maintained their weight or gained some during the first year, despite making lifestyle improvements. Even so, about 22 percent of these individuals were able to return their blood sugar to a normal range. Over an additional follow-up period of up to nine years, those who normalized their blood sugar without losing weight had a 71 percent lower risk of developing type 2 diabetes. This result was nearly the same as that of participants who achieved weight loss (73 percent risk reduction).

The Role of Fat Distribution

The researchers also examined how fat was distributed in the body. They compared visceral fat (the fat stored deep in the abdomen around the organs) with subcutaneous fat (the fat beneath the skin). Visceral fat produces signaling molecules that can trigger inflammation and disrupt hormone balance, leading to insulin resistance and increasing the risk of diabetes. Participants who normalized their blood sugar without losing weight showed a reduction in abdominal fat compared to those who remained in the prediabetic range, suggesting fat distribution may be a critical factor.

Looking Beyond the Scale

"Restoring a normal fasting blood sugar level is the most important goal in preventing type 2 diabetes and not necessarily the number on the scale," says Prof. Dr. Andreas Birkenfeld, study leader and director of the Institute for Diabetes Research and Metabolic Diseases (IDM) of Helmholtz Munich at the University of Tübingen. "Exercise and a balanced diet have a positive effect on blood sugar levels, regardless of whether weight is reduced. Losing weight remains helpful, but our data suggests that it is not essential for protection against diabetes," he continues. "In future, guidelines for the prevention and treatment of type 2 diabetes should not only take weight into account, but above all blood glucose control and fat distribution patterns," adds Prof. Dr. Reiner Jumpertz-von Schwartzenberg, who, as last author, was involved in the study alongside Prof. Dr. Birkenfeld.

Lifestyle Habits That Make a Difference

The findings emphasize the importance of targeting healthy blood sugar values (known as glycemic targets) alongside weight-related goals in diabetes prevention. Achieving remission from prediabetes appears to be one of the most effective ways to avoid developing type 2 diabetes, and this can occur even without weight loss. Still, maintaining regular physical activity and a balanced diet remains essential for keeping blood sugar levels within a healthy range.