Thursday, December 29, 2011
DANGER: THE RETURN OF THE FAT
Perhaps an article published in the American Journal of Clinical Nutrition will provide some extra incentive. The study shows that older women who lose weight tend to gain it back again as fat not muscle.
Barbara Nicklas, Ph.D., a gerontologist at the J. Paul Sticht Center on Aging and Rehabilitation at Wake Forest Baptist and principal investigator for the study put it rather frankly :
"The body composition of some of the women was worse than before their weight loss ... When older women lose weight, they also lose lean mass. Most women will gain a lot of the weight back, but the majority of the weight regained is fat."
Dr. Nicklas and her colleagues evaluated 78 postmenopausal women with an average age of 58. The women were chosen with a criteria of having lost around twelve percent of their body weight as part of a study from a dieting program. Their change in body mass composition was recorded at the end of the weight loss program, comparing muscle with fat components. It was then measured again six and 12 months later. During the year of study the women did not follow any further weight loss program.
The aim of gathering the data was to establish whether women who regained weight did so in accordance with their original body mass ratios. At the end of the study, 53 of 78 (68 percent) of the women at the six-month follow-up and 52 of 68 (76 percent) the women at the 12-month follow-up had regained some of their lost weight. Eleven women (16 percent) weighed more at the 12-month follow-up than they did at baseline, and 16 (24 percent) women continued losing weight after the intervention.
Of those who regained weight, three quarters gained more than four pounds in the following six months and this number increased to nearly 85% at the twelve month mark. The so called "regainers" were then used to evaluate the type of body mass that constituted their weight gain.
Unfortunately for dieters everywhere, it appears that fat was regained far faster than muscle. At the beginning of the study it was assessed that the weight loss consisted of one third muscle (33%) and two thirds fat (67%), whereas the weight regain showed 81 percent fat and only 19 percent muscle.
As Dr. Nicklas points out :
"Most people will regain their weight after they lose it ... Young people tend to regain weight in the proportion that they lost it. But the older women in our study did not appear to be regaining the muscle that they lost during initial weight loss in the same way."
Post menopausal women already have it tough with hormonal changes and loss of bone density already known to occur, so losing muscle mass, and worse still, replacing it with fat, is probably the last thing they should be doing. It puts the issue of dieting at this age into a certain perspective and might even make those who need to lose weight for health reasons, more likely to consider surgical options with more reliable outcomes. As Dr. Nicklas puts it :
"There are certainly a lot of health benefits to weight loss, if you can keep the weight off ... For older women who lose weight, however, it is particularly important that they keep the weight off and continue to eat protein and stay physically active so that, if the weight does come back, it will be regained as muscle instead of fat."
The researchers cautioned that their study involved only sedentary abdominally obese, postmenopausal women, and the findings may differ in men or in younger populations - obviously future studies are needed to look at other sectors of the population. None the less, it's an interesting and useful study that will help doctors and patients alike to choose weight loss options more wisely. The researchers concluded that :
"Many health complications associated with overweight and obesity are improved with weight loss ... However, negative consequences (such as loss of muscle mass and bone density) are also associated with weight loss and are detrimental for older adults, which results in a reluctance to recommend intentional weight loss in this population...Because lean mass loss in older adults may be associated with the development of adverse health events and disability, it is important to examine whether the benefits of weight loss outweigh the risks in this population."
Nicklas' co-authors are: Kristen M. Beavers, Ph.D., Mary F. Lyles, M.D., Cralen C. Davis, M.S., and Daniel P. Beavers, Ph.D., all of Wake Forest Baptist; and Xuewen Wang, Ph.D., of Washington University School of Medicine, in St. Louis, MO.
Written by Rupert Shepherd