But, on the other hand, if you're worried about the risks of losing weight late in life, don't be.
Two studies released in today's issue of Archives of Internal Medicine give insights into the dangers and myths of weight gain and weight loss for older men.
The first study adds stroke to the list of primary risks from obesity. The second concludes that middle-age and elderly men shouldn't fear the weight fluctuation that often results from healthy dieting.
"The problem is that in the United States, the number of people who are overweight is rapidly increasing. This should give another reason to stay lean," says the lead author of the first study, Dr. Tobias Kurth, with Brigham and Women's Hospital in Boston.
Kurth and a team of doctors associated with Harvard Medical School examined 12.5 years of health records for 21,414 men, ages 40 to 84. The participants were all doctors who reported information from 1982 to 1995 as part of the Physicians' Health Study.
The researchers found that obesity was a major risk factor for stroke, independent of high blood pressure, diabetes, cholesterol and other common indicators.
Obesity has long been associated with heart disease, the leading cause of death in the United States. But obesity hasn't been clearly tied to stroke, the third-leading killer, because prior studies were too small, Kurth says.
"I think that we should view obesity as a primary risk factor and not a potential, secondary risk factor," Kurth says. "I think that this study's size and the methodology is strong enough for us to increase our focus on obesity."
In fact, the size of the study allowed Kurth to devise a simple formula showing how adding pounds increases the risk of stroke. For most men, an increase in weight of seven to eight pounds results in a 6 percent increase in the risk of stroke, he says.
To more accurately track how weight gain affects risk of stroke, men should calculate their body mass index, which shows the relationship between weight and height. According to the World Health Organization, a BMI less than 25 is normal, 25 to 30 is overweight, and over 30 is obese. According to Kurth, a point increase in BMI increases stroke risk by 6 percent.
"People should focus more on obesity," Kurth says. "Obesity is modifiable. You can reduce your risk of stroke if you can stay lean."
The other study should give older men more faith in the process of losing weight.
Doctors, supported by a few studies, had worried that losing weight and weight "cycling" -- gaining and losing weight through dieting -- was unhealthy for men. But a 12- to 14-year British study of 5,608 middle-age men concludes that "this belief is a barrier to the management" of obesity. The men came from 24 towns in England, and the study evaluated mortality rates for them from 1978 and 1980 to 1992.
Although the study found that men who experienced sustained weight loss or weight fluctuation were at greater risk of death than those who maintained a stable weight, the culprit wasn't weight cycling, says lead author S. Goya Wannamethee, of the Royal Free and University College Medical School in London. When the researchers adjusted the results for pre-existing diseases and smoking, those men who experienced weight fluctuation were at no greater risk of death, he says.
"Many of the earlier studies did not take pre-existing disease or smoking adequately into account," Wannamethee says. "Authorities should continue to encourage and facilitate healthy eating and regular activity towards the prevention and management of obesity."
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