It is well known that obesity is associated with a great number of health problems, and weight loss could improve such complications. It is also known, however, that some effects of weight loss including loss of muscle mass and bone density can have negative side effects, especially for the older population. Only about 20% of people who undergo a significant, deliberate weight reduction are able to keep it off for the long term.
The majority of people who successfully lose weight on a diet will regain it at a later point. The composition of fat and lean tissue loss during weight loss has been previously examined, but the composition of the weight eventually re-gained is not well understood. This study was done to see if the fat composition of weight re-gained was similar to th95 women fromNorth Carolinawere recruited for this study. These women had abdominal obesity with waist circumference of >88 cm, and were between the ages of 50-70 years old, post-menopausal, and had been weight stable for > 6 months prior to enrollment.
95 women fromNorth Carolinawere recruited for this study. These women had abdominal obesity with waist circumference of >88 cm, and were between the ages of 50-70 years old, post-menopausal, and had been weight stable for > 6 months prior to enrollment.
The women were placed into three groups; one receiving only a calorie restricted diet, the second receiving a calorie restricted diet + a moderate intensity aerobic exercise plan, and the third group receiving the same calorie restricted diet + a vigorous intensity exercise plan. Anthropometric and body composition measurements were taken. Individual energy needs were determined to achieve a caloric restriction of ~400 kcal/day for 5 months, and then were asked to return 6 and 12 months later. The women were given one counseling session with a registered dietitian to discuss maintenance of weight loss, but no other support. All 95 women completed the weight loss program and 68 returned after 12 months.
Initial weight loss was not significantly different between experimental groups and loss consisted of 67% fat and 33% lean tissue. 85% regained weight at the 12 month follow-up, and weight regain consisted of 81% fat and 19% lean tissue. In addition, after 12 months, the waist-to-hip ratio decreased significantly.
Many of the women in the study successfully lost weight (>10% body weight) in the initial 5 month program, and 46% kept it off at one year, which is considered a high success rate. This is likely attributed to the all –female demographic of the group studied, as the female gender is a recognized predictor of maintaining weight loss. Also, the group of women who volunteered responded to advertisements, suggesting they were very motivated to lose weight, and this could have skewed results.
People who regain weight after a weight loss program could regain it in a manner that results in a reduced lean-to-fat mass ratio, meaning that fat is gained to a greater degree than lean mass. Despite this unfavorable ratio, many who lose weight only experience partial weight regain and therefore weigh less than they had before the weight loss program.
The full text, titled “Is lost lean mass from intentional weight loss recovered during regain in postmenopausal women?” Can be found in the American Journal of Clinical Nutrition, volume 94, pages 767-774. (2011). The authors are K.M. Beavers, M.F. Lyles, C.C.Davis, X. Wang, D.P. Beaver and B.J. Nicklas.
Written by Kaitlin Bennett and Rachel Jackson, Dept. Nutritional Sciences, Rutgers University-NewBrunswick Edited by SA Shapses PhD, RD