Older dieters need to exercise too: study

NEW YORK (Reuters Health) - For older adults who want to shed pounds, exercise may be even more important than cutting calories, new research suggests.

In a study of 34 adults in their 50s and 60s, researchers found that both dieters and exercisers lost weight. The exercise group, however, did so while maintaining their muscle mass, strength and fitness levels, whereas dieters showed declines in all these measures.

The findings, published in the Journal of Applied Physiology, suggest that exercise has added benefits over dieting alone.

"Exercise-induced weight loss provides the additional benefit of improving physical performance capacity," lead author Dr. Edward Weiss, of Saint Louis University, said in a statement.

Muscle mass and cardiovascular fitness naturally decline with age, so it's particularly important for older adults to try to preserve their strength and fitness levels as they lose weight.

"If push comes to shove," Weiss said, "and somebody wants to know if they should diet or exercise to lose weight, I would suggest exercise, provided they are willing to put in the extra time and effort and not offset the gains they make by eating more."

The study findings are based on a one-year follow-up of healthy older adults who were randomly assigned to either exercise or cut calories to lose weight.

The dieters had weekly meetings with a dietitian to discuss ways to alter their eating habits, while the exercise group met with a trainer each week.

The average weight loss in each group was nearly identical -- about 17 pounds over one year. But while dieters lost muscle mass, strength and endurance, exercisers preserved theirs.

The difference, according to Weiss, is not only a matter of the exercisers' workouts. As people lose weight, even their everyday movements begin to present less of a challenge to their muscles, leading to a decline in muscle size and strength.

None of this, however, means diet and nutrition don't matter, the researcher stressed. The way we eat is vital for overall health, and is key for weight loss even for people who exercise, according to Weiss.

Working out won't make a weight difference, he noted, if exercisers replace the burned calories by eating more.

SOURCE: Journal of Applied Physiology, November 9, 2006.