Exercise vs. Diets: Weighing the Benefit

Study Shows Older Exercisers Burn More Fat Than Those Who Only Diet

From the WebMD Archives

Sept. 19, 2008 -- There's even more evidence that it is never too late to start exercising.

When overweight older people start walking or riding a stationary bike, they are able to improve their exercise efficiency, according to a new study. Exercise efficiency refers to using fewer calories to perform a physical activity.

Also, exercisers burn more fat and lose less muscle than older people who simply diet for weight loss. People tend to lose lean muscle mass as they age, and if they lose too much, it can interfere with the activities of daily living.

"The take-home message is that, even among older people and during a fairly short period of time, exercise produces metabolic changes that require the expenditure of fewer calories during physical activity. Exercise also allowed older people to more preferentially burn fat, which may be healthier metabolically," says researcher Bret Goodpaster, PhD, of the University of Pittsburgh, in a news release.

The study is published in the Journal of Applied Physiology. University of Pittsburgh researchers divided 64 sedentary participants, all between the ages of 60 and 75 and all either overweight or obese, into three groups. There were the dieters, the exercisers, and a group that both dieted and exercised for four months.

Dieters reduced their caloric intake enough to achieve a 10% weight loss by the end of the four-month study period. Exercisers could either walk, bike, or row three to five times a week for four months. Most of the exercisers chose to walk.

The exercise-only group increased efficiency compared to the diet-only group. The diet-and-exercise group also increased efficiency compared to the diet-only group.

As for burning fat, the exercisers again came out ahead. All three groups lost weight; the diet-only and diet-and-exercise groups lost more weight than the exercise-only group. The diet-only group lost more lean muscle and fat. The exercise-only and diet-and-exercise groups drew more on fat stores as an energy source.

WebMD Health News Reviewed by Louise Chang, MD on September 18, 2008



Amati, F. Journal of Applied Physiology, 2008; vol 105: pp 825-831.

News release, The American Physiological Society.

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