A few simple lifestyle changes, like walking most days and eating a healthier diet, go a long way towards preventing diabetes, according to a new National Institutes of Health (NIH) study. These changes reduced the risk of developing type 2 diabetes by almost 60 percent in both men and women, in both young people and seniors and in all ethnicities.
The study, known as the Diabetes Prevention Program (DPP), was a major clinical trial comparing the effects of diet and exercise alone to treatment with the oral diabetes drug metformin. More than 3,000 overweight people with impaired glucose tolerance, a condition that often progresses into full-blown diabetes, were followed for three years. Those who ate a lower fat diet, exercised by walking 30 minutes a day, and achieved an average 15-pound weight loss reduced their risk for diabetes by 58 percent. The results were so definitive that the trial was concluded a year earlier than planned.
Surge in Diabetes
Type 2or adult onset diabetes occurs in about 6.5% of the U.S. population or 16 million people. It increased at a staggering rate during the past decadefrom 1990 to 1998 diagnoses, including gestational diabetes, rose 33 percent. New statistics show that rates rose a striking 6% among adults in 1999. It's no coincidence that the rise in diabetes mirrors that of another dietary-related disease, obesity.
What's alarming is that children and adolescents are now developing it, when formerly the disease only struck people over 40. The American Diabetes Association conservatively estimates between 10-15% of newly diagnosed kids and teens have type 2 diabetes, (rather than the type 1 that typically affects younger people) although rates may range as high as 45%. It also rose at an alarming rate among people in their 30s.
Of the 3,234 people enrolled in the DPP, 45 percent were from minority groups at higher risk of type 2 diabetes: African Americans, Hispanic Americans, Asian Americans, Pacific Islanders and American Indians. Other groups studied included people 60 years and older, women with a history of gestational diabetes, and people with close relatives with type 2 diabetes. The lifestyle changes were as effective in men as in women and in all ethnic groups. Even people aged 60 or older, of whom almost 20 percent have diabetes, reduced their risk by 71 percent.
The drug metformin, also known as Glucophage®, reduced risk by an average of 31 percent. This was true for men and women and all ethnic groups, but it did not have the same effectiveness in the older age groups.
More on Lifestyle Changes
People in the study were placed on a weight loss dietbetween 1,200 and 1,800 calories a daywith about 25 percent of total calories coming from fat. (This is a significant reduction in fat from the average American's 35 percent, but not as low as some extreme weight loss diets.) Participants exercised moderately by walking for 30 minutes at least five days a week, or did similar activities like swimming or tennis. These simple measures produced a 5 percent to 7 percent loss in body weightenough to make a big difference in their health.
Because so many people fail at lifestyle changes, participants were given a lot of support. They visited a nutritionist once a week for almost six months, received personal coaching for their fitness activities and participated in healthy cooking and grocery shopping classes. Daily food and activity records were a must.
One question not answered by the study is whether diabetes can be prevented or delayed beyond a three-year period. Researchers plan to continue following the study participants to learn how long their lifestyle changes will be effective. Another question is whether diet and exercise will also reduce cardiovascular disease and atherosclerosis, the major causes of death in people with diabetes.