NEW YORK (Reuters Health) – A combination of diet and exercise may help overweight older adults lose pounds without losing muscle, a new study suggests.

The study, which followed 64 overweight or obese adults ages 60 to 75, found that those who lost weight through diet and exercise became more fit and preserved more muscle mass than those who shed pounds by dieting alone. Exercise also helped the study participants burn more fat for fuel.

The findings suggest that the best way for older adults to lose excess weight is through diet and exercise together, according to the researchers.

“Exercise seems to be the key for maintaining muscle mass when older adults lose weight through dieting,” Dr. Bret H. Goodpaster of the University of Pittsburgh, one of the researchers on the study, told Reuters Health.

In addition, he said, some other benefits of exercise — like increased fitness and fat-burning capacity — are not seen with diet alone.

Goodpaster and his colleagues report the findings in the Journal of Applied Physiology.

In their study, the researchers randomly assigned overweight, sedentary older adults to one of three groups: a reduced-calorie diet; a supervised exercise regimen; or a reduced-calorie diet plus the exercise program.

After 16 weeks, all three groups had lost weight, on average – but the diet-only and diet-plus-exercise groups were more successful than the exercise-only group.

However, dieters lost substantially more muscle mass compared with their exercising counterparts, the researchers found. What’s more, both exercise groups improved their fitness levels and boosted their body’s fat-burning capacity.

Preserving muscle mass is important for older adults, as frailty increases the risks of disability and disease. Weight loss, though healthy for people who are overweight or obese, also often includes muscle loss — a problem that can be countered with regular exercise, the current findings suggest.

However, Goodpaster said, older adults who want to start exercising should first see their doctors for a routine physical exam.

SOURCE: Journal of Applied Physiology, September 2008.