Wednesday, 08 November 2006

Which works best in helping you lower your risk for diabetes - exercise or diet?

Call it a toss up, because both diet and exercise provide profound benefits to reduce the risk of diabetes, a university nutrition expert says.

"Both those who restrict calories and those who exercise benefit from weight loss," says Dr. Edward Weiss, an assistant professor of nutrition and dietetics at Saint Louis University, who finished a study recently on diabetes and its risk factors. "We thought exercise probably would produce greater benefits. But both of these are providing beneficial health improvements."

More than 20 million children and adults in the United States have diabetes - and a third of them don't know it. More than 54 million Americans stand on the cusp of becoming full-blown diabetics, according to the American Diabetes Association.

Diabetes occurs when the body fails to produce or properly use insulin, a hormone needed to convert sugar, starches and other food into energy. Although health experts don't know the cause, they believe that genetics, obesity and lack of exercise appear to play roles.

At least 10 million Americans at high risk for type 2 diabetes - the most common form of the disease - can lower their chances of getting the disease sharply with diet and exercise, according to federal government's National Institute of Diabetes & Digestive & Kidney Diseases.

Throughout the country, researchers are trying to find ways that will allow people to lower their risk of diabetes or help diabetics lead healthier lifestyles.

Weiss serves on a team of scientists at Washington University at St. Louis, Mo., who are looking at whether a calorie-restrictive diet can extend a person's lifespan.

In a project involving people 50 to 60 people, Weiss and the team focused on markers for developing diabetes because the disease is one of the main causes of premature death. The study participants were either at the high end of the normal-weight range or just a tad overweight, but none suffered from obesity..

They were divided among diet, exercise and comparison groups. All got their insulin action and glucose tolerance - both major markers for diabetes - measured at the beginning and end of the project.

In addition, their weights, body compositions and energy intakes were measured at the beginning of the study and again at five separate times during the project.

The people who were on restricted calories met weekly with a dietitian who help develop menu plans and guide them in reducing the portions of food they ate, and replacing high calorie foods with lower calorie choices. Their goal was to reduce their calorie consumption by 16 percent and then 20 percent.

People in the exercise group strove to burn 16 percent more calories for the first three months and then 20 percent the next nine months. They met weekly with an exercise trainer and had open access to a fitness center.

To meet their goals, they exercised from 60 minutes to 90 minutes a day. As they got fit, they could speed up their treadmills and make the grades steeper so they could burn more calories.

In the comparison group, only a few members requested general advice on healthy eating and got free passes to a yoga class

However, for both dieters and those who exercised, their glucose tolerance and insulin levels improved at about the same levels. They also lost weight. But those in the comparison, or "control," group didn't lose weight or see changes in their glucose and insulin levels, Weiss says.

"The next step is to determine what happens when you exercise and diet to lose weight," Weiss says. "We don't know if the combination is going to provide greater benefits."

Source: Saint Louis University Medical Center
Reference: American Journal of Clinical Nutrition, November issue