Sunday, January 29, 2012

Resistance Training

In a recent study performed at Wake Forest Baptist Medical Center in Winston-Salem, North Carolina, researchers wanted to determine whether the composition of body weight (fat vs. muscle) regained after intentional weight loss is similar in composition to the body weight that was lost.

Muscle is a metabolically active tissue, which means that it's burning calories even while we are at rest. Fat mass, on the other hand, is relatively inactive tissue; it keeps us warm and protects our organs, but it's not burning any calories. These facts are important to keep in mind when thinking about losing weight and maintaining lost weight.

This study included 78 women with an average age of 58, who recently lost about 25 pounds. Researchers assessed body composition (muscle mass vs. fat mass) immediately after the weight loss, then at 6 and 12 months after the end of the weight loss period.

They found that when the participants lost weight, about 30% of that was due to a loss of muscle mass. When the regainers gained weight over the course of the next year, only 20% of the weight regained was muscle. This means that the women gained back a higher proportion of fat than they lost. For most people, losing that metabolically active muscle tissue and regaining fat makes it harder to lose weight in the future.

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