Loss of lean mass could have important consequences given the high risk of physical disability among the growing population of older adults.
The findings:
- Total fat loss was much greater when participants combined diet plus walking (about 16 pounds) and diet plus weight training (about 17 pounds). Diet alone resulted in about 10 pounds of fat lost over 18 months.
- Muscle mass loss was greatest with diet plus walking (about 4 pounds) compared with diet alone or diet plus weight training (each about 2 pounds). Put another way, the percentage of weight loss coming from muscle mass was 20% in the weight loss plus walking group, 16% in the weight loss alone group, and 10% in the weight loss plus weight training group.
- Loss of fat was associated with faster walking speed, while loss of muscle was associated with reduced knee strength.
These results may be even more important for older adults who gain and lose weight with frequency, because seniors typically don’t regain muscle – they regain fat mass – which is “all the more reason for older adults to try and preserve muscle mass during weight loss,” Beavers said.
This is the latest study from the Cooperative Lifestyle Intervention Program (CLIP-II), a single-blind, randomized controlled trial. The participants were randomly assigned to one of three groups: a weight-loss-only group, who followed a calorie-restricted diet with no exercise regimen; a weight loss plus cardio (i.e., walking) group; and a weight loss plus weight-training group.
Co-authors on this paper included W. Jack Rejeski and Anthony Marsh, co-principal investigators of the CLIP-II study, and Jessica Sheedy, Beverly Nesbit and Jill Gaukstern, all of the Wake Forest University Department of Health and Exercise Science; and Walter Ambrosius, Michael Walkup, Jonathan Burdette and Barbara Nicklas of the Wake Forest School of Medicine.
The research was funded by a grant from the National Institutes of Health/National Heart, Lung, and Blood Institute. Partial support also comes from grants by the National Institute on Aging.
