October 1, 2025, 2:36 pm | Read time: 6 minutes
Around ten percent of adults in Germany have been diagnosed with diabetes. Of these, over 90 percent are affected by type 2 diabetes, which can often be prevented through a healthy lifestyle. German researchers have now discovered that weight loss is not crucial for protection against the disease. Apparently, other factors play a more important role.
In type 1 diabetes mellitus, insulin production is genetically impaired, so those affected rely on insulin injections for life to regulate their blood sugar levels.1 Type 2 diabetes mellitus, on the other hand, develops over a period of years due to an unhealthy lifestyle. This also leads to impaired insulin production or insulin resistance. The precursor to this is called prediabetes and is characterized by persistently slightly elevated blood sugar levels. Especially at this stage, those affected can counteract it with a healthy lifestyle, consisting of a balanced diet and plenty of exercise.
Until now, weight loss has been considered one of the most important recommended measures. But in a recent study, German researchers found that people who shift their blood sugar levels to the normal range through lifestyle changes can reduce their risk of type 2 diabetes by 71 percent, even without weight loss.2 Body weight alone is apparently not the most important factor for prevention.
How Did the Study Researchers Proceed?
Under the leadership of the Tübingen University Clinic for Diabetology, Endocrinology, and Nephrology, a long-term study observed over 1,100 prediabetes patients after a lifestyle change. The participants’ ages ranged from 18 to 75 years. The data for this was drawn from an ongoing multicenter study by the German Center for Diabetes Research. It included participants from all over Germany. The prediabetes participants underwent a twelve-month healthy lifestyle change and were then followed for up to nine years.
The measurement methods included metabolic phenotyping, oral glucose tolerance tests for glucose metabolism, and whole-body magnetic resonance imaging (MRI) to assess body fat distribution before and after treatment and during the follow-up period. The goals of the healthy lifestyle change included the following aspects:
- Reducing fat intake to less than 30 percent of total energy intake
- Saturated fats should make up less than 10 percent of total energy intake
- Increasing fiber intake to more than 15 grams per 1,000 kilocalories of total energy intake
- Increasing physical activity and fitness, such as by increasing the number of steps per day and engaging in sports activities
Study Results Show: Body Weight Plays a Minor Role in Diabetes Prevention
The data analysis led to exciting insights. Of the original 1,105 prediabetes participants, 234 (21.2 percent) did not lose weight or even gained weight during the one-year lifestyle change. However, 51 of these individuals returned to normal blood sugar levels, about 22 percent. Remarkably, this group had up to a 71 percent lower likelihood of developing type 2 diabetes without weight loss. Particularly interesting: The likelihood decreased almost as much as in participants who lost weight (73 percent lower risk for type 2 diabetes). The researchers conclude: A healthy lifestyle is more important than focusing solely on weight loss.
“Restoring a normal fasting blood sugar level is the most important goal for preventing type 2 diabetes and not necessarily the number on the scale,” comments study leader Prof. Dr. Andreas Birkenfeld in a press release from the University of Tübingen.3 According to Dr. Birkenfeld, exercise and a balanced diet have a positive effect on blood sugar, regardless of whether weight is reduced. “Losing weight remains helpful, but our data suggests it is not necessarily required for diabetes protection,” he adds. “The guidelines for the prevention and treatment of type 2 diabetes should in the future consider not only weight but especially blood sugar control and fat distribution patterns,” adds Prof. Dr. Reiner Jumpertz-von Schwartzenberg, the study’s last author.
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Body Fat Distribution Also Plays an Important Role in Diabetes Prevention
But the researchers found another important connection: Body fat distribution is a decisive factor for diabetes risk. During the study, the participants’ body fat distribution was also measured. The ratio between visceral fat and subcutaneous fat was determined. A high visceral fat content is considered particularly unhealthy because it surrounds organs and releases signaling substances that promote inflammation and disrupt hormone balance. This, in turn, leads to insulin resistance, which is why visceral fat is directly linked to type 2 diabetes, as the scientists explain. Less harmful, however, is subcutaneous fat, which is located under the skin.
In the study, participants whose blood sugar levels normalized without weight loss had a lower proportion of abdominal fat solely through lifestyle changes compared to those whose blood sugar levels remained in the prediabetes range. Therefore, the researchers advise focusing more on this factor in diabetes prevention.
Our Nutrition Expert’s Assessment of the Study
FITBOOK asked diabetologist and nutritionist Dr. Matthias Riedl about the study. We wanted to know if he also recommends focusing less on weight loss and more on normalizing blood sugar in the treatment of prediabetes. “The two cannot be separated,” is the expert’s assessment. “However, blood sugar levels are the direct effect size that needs to be improved. They reflect the performance of the metabolic system around the pancreas. This has been overlooked in diabetology so far.” This is also why some type 2 diabetes patients could be cured with even slight weight reduction, while in other patients, even losing 20 kilograms did not lead to remission.
According to Dr. Riedl, the extent of insulin resistance or damage depends on various factors:
- visceral fat mass (unfortunately, often not measured)
- the type of fat distribution
- extent of diabetogenic food choices—how much one reduces unhealthy eating habits
Therefore, Dr. Riedl advises focusing specifically on diet to lower blood sugar levels. His experience shows: “Highly processed foods make up over 50 percent of the diet for many. Too much sugar, too little fiber, too much wheat. Changing this can lead to significant success in combating type 2 diabetes and prediabetes, even at the same weight.”
He also sees visceral fat as an important factor that can lead to diabetes. According to Dr. Riedl, visceral fat is a diabetes risk factor and is also responsible for many other lifestyle diseases. “Those who have developed prediabetes because of it, however, have a good chance of recovery. People with prediabetes without excessive visceral fat as a cause must do more in the area of antidiabetic nutrition. If this fat melts away, prediabetes usually disappears as well,” the expert states.
Overall, the study shows the long-overdue need to not treat weight loss as dogma and to focus more on other factors. “It was time to establish antidiabetic nutrition as the most important pillar, followed by weight reduction and then exercise,” explains Dr. Matthias Riedl.