Aug. 21, 2000 — Good news for some overweight adults. While it’s highly recommended they lose weight to ward off diabetes, they don’t have to do it overnight, and they don’t have to lose a ton to significantly reduce their risk. But on the other side of the coin, increased weight gain adds to their risk.
In a study of nearly 2,000 overweight, nondiabetic adults between the ages of 25 and 74, researchers investigated whether people who were already at high risk for developing diabetes reduced their risk by losing weight.
For the study, ‘overweight’ was defined using a common calculation based on weight and height called the body mass index (BMI). For instance, a woman was considered overweight with a BMI of just over 27, which would be about 5 foot 4 inches tall, weighing about 157 pounds. An overweight man had a BMI near 28, which is about 5-foot-9, weighing 183 pounds. These numbers are based on the United States National Health Objectives from Healthy People 2000.
The annual weight change of the participants over 10 years was calculated using weight at the beginning of the study and on average, 10 years later. In the 10 years after the initial measurement, any development of diabetes was determined by questioning the patients or looking at hospital discharge records and death certificates.
Researchers discovered that if just over 2 pounds of weight was lost each year for 10 years the risk of developing diabetes was reduced by a third. “For a normal weight person that may seem like a lot of weight,” says study author Helaine Resnick, PhD, an epidemiologist with Medstar Research Institute in Washington, D.C. “But it’s not for someone who is very overweight.”
The study, which appeared in the August 2000 edition of the Journal of Epidemiology & Community Health, showed just the opposite risk for people who gained weight during the same period. A gain of just over 2 pounds each year over 10 years was associated with a 49% increased risk of getting diabetes in the future, when compared to other overweight people in the group whose weight simply remained stable.
Resnick says this study may offer hope to some people who feared they didn’t have much control over whether they would get diabetes. “Many overweight people believe that if they’re already overweight, losing weight is not going to help them,” she says. “We found just the opposite, even for high-risk groups like those in our study.”
According to the American Diabetes Association and the National Institutes of Health, more than 16 million Americans have diabetes, a group of serious diseases characterized by high blood sugar levels that result from defects in the body’s ability to produce and/or use insulin. Diabetes can lead to serious complications, such as blindness, kidney disease, heart disease, and amputations. It is also the sixth-leading cause of death by disease in the U.S.
Type 2 diabetes — formerly called non-insulin-dependent or adult-onset diabetes — usually arises because of insulin resistance, in which the body fails to use its own insulin properly. The disease tends to occur in overweight adults, although it is being seen increasingly in obese children. When a person is overweight, insulin cannot work as effectively to keep blood glucose levels normal because the body becomes resistant to the action of its own insulin.
It is estimated that people who are overweight have three times the risk of developing type 2 diabetes, compared to normal weight individuals. But Resnick says it wasn’t the purpose to the study to find the most effective ways to lose weight. “However, conventional wisdom dictates that a lifestyle change — eating modifications and exercise — can reduce diabetes risk as well as many, many health benefits,” she says.
Jaakko Tuomilehto, MD, a professor at the National Public Health Institute in Helsinki, Finland, agrees. His research, completed in 1999, showed that weight loss and moderate exercise together can yield even greater results. “Lifestyle modification reduced the incidence of type 2 diabetes by 58% in people at high risk for the disease,” says Tuomilehto.
Tuomilehto’s Finnish Diabetes Prevention Study included over 500 adults about age 55, who had impaired glucose tolerance, a state in between ‘normal’ and ‘diabetes,’ in which the body is no longer using and/or secreting insulin properly. His subjects had average BMIs of 31, which would be a man about 5-feet-6, weighing 205 pounds.
Tuomilehto says that one of the reasons he proposes lifestyle changes is that most people who lose weight tend to gain it right back. “It’s only when they become committed to improving their health that results become long-lasting,” he says.