New research has found that the belief that intentional weight loss is harmful to older adults is unfounded.
The study, conducted by scientists at Wake Forest University Baptist Medical Center, will be published in the Journal of Gerontology: Medical Sciences.
According to M. Kyla Shea, first author on the study and a research associate in the Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, the study demonstrates that seniors who intentionally exercised and/or modified their diets to lose weight were half as likely to die within eight years of follow-up as their peers who did not work toward weight loss.
Shea said: "It was an unusually strong and surprising finding.
"Our data suggest that people should not be concerned about trying or recommending weight loss to address obesity-related health problems in older adults."
Prior to this study, research that has looked at the association between mortality and weight loss has not factored in the many different potential causes of the weight loss.
So, using a more rigorous randomised trial approach, Shea and colleagues sought to prove or disprove the idea that older individuals who actively tried to lose weight increased their risk of death.
The researchers re-analysed data from a study of 318 community-dwelling, older adults over age 60, all with knee arthritis, who were enrolled in a trial assessing the effects of weight loss and/or exercise on physical function in the late 1990s.
The initial weight-loss intervention took place over a period of 18 months from 1996 through 1998, during which time the 159 individuals in the intervention groups actively lost an average of 10.5 pounds. The non-intervention group lost an average of 3.1 pounds naturally.
The study team then checked to see if the study participants were still living eight years later.
Shea said: "Overall, we found that there were far fewer deaths - half the number - in the group of participants that lost weight compared to the group that did not."
The finding came as a surprise to gerontologists.
Stephen B. Kritchevsky, director of the J. Paul Sticht Center on Aging at the Medical Center, said: "For years, the medical community has relied on multiple epidemiological studies that suggested that older people who lost weight were more likely to die.
"Weight loss in old folks is just understood to be a bad prognostic sign. The data that people have been using has been unable to separate the cause and effect of the weight loss, however, and our study suggests that the weight loss they've been studying may be the result of other health problems and not of intentional weight loss."
The participants in this study had a constellation of common health problems occurring in aging adults, Kritchevsky added.
He said: "These were the seniors living out in the community, getting around and doing their daily tasks just like your neighbor.
"All were overweight and dealing with the signs of aging when the study started."
When the researchers evaluated the effect of weight loss in the oldest of the participants - 75 and older - they found the same reduction in mortality as they saw in the younger group - those 60 and older - who lost weight.
Weight loss in older adults has been shown to help several medical problems such as high blood pressure, high cholesterol and high fasting glucose levels, Kritchevsky said.
However, physicians have been hesitant to recommend weight loss in older adults because of a concern for mortality based on previous research.
"This study puts to rest a lot of unfounded concerns about how to address the epidemic of obesity among our older adults," Kritchevsky noted.