Losing a small amount of weight doesn't appear to lower the risk of heart attacks and strokes in people with diabetes who are already getting good medical care, according to a long and expensive clinical experiment whose results were announced Friday.
While modest weight loss has benefits in how overweight diabetics feel, sleep and move, whatever benefit it may confer in preventing cardiovascular disease - which is what most diabetics die from - is too small to measure, the study found.
"We were hoping that a weight-loss program would help reduce cardiovascular disease, but now we have the answer that it doesn't," said Mary E. Evans, a physician at the National Institute of Health's National Institute of Diabetes and Digestive and Kidney Diseases, which paid for the study.
The results will probably surprise many physicians and patients but are not likely to change the advice they give and get.
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"We feel that there are many reasons why people with type 2 diabetes should control their weight," said Rena R. Wing, the researcher at Brown University's Miriam Hospital in Providence, R.I., who headed the experiment.
The study, which began in 2001, was scheduled to last two more years. In mid-September, however, an independent monitoring board advised NIH that it be stopped in its current form because the weight-loss "intervention" wasn't having its hoped-for effect.
The Look AHEAD (Action for Health in Diabetes) trial involved hundreds of doctors, nurses, dietitians and exercise therapists at 16 medical centers. It cost about $20 million a year, or about $220 million over its 11-year-life.
The researchers recruited 5,145 people with type 2 diabetes, which is the form that generally comes on in adulthood and is strongly associated with being overweight.
About 60 percent of the volunteers were women and slightly more than one-third were minorities. The average age was 58.
Half were randomly assigned to get intensive dietary counseling on how to limit their calories. They were provided meal substitutes such as Slimfast drink. They met weekly in support groups and once a month with a counselor. The other half got less intensive diet and exercise advice, at first four times a year and later just once a year.
Over the decade of the study the first group maintained an average 5 percent reduction from their starting weight - about 10 pounds. The people in the less-intensive group lost, on average, about 1 percent of their body weight.
By the end of 11 years, there was no difference between the two groups in the rate of heart attack or stroke.
