Eating Less Reduces Fitness - But Exercise Preserves It

By Maureen Williams, ND
Healthnotes Newswire (January 4, 2007)—Eating fewer calories is one way to lose weight, but exercise needs to be part of the program to preserve muscle mass and physical fitness, a new study demonstrates.
For overweight and obese people, weight loss can reduce their risk of heart disease, diabetes, and some cancers. The formula for weight loss is simple: the calories burned in activity must exceed the calories taken in as food; in other words, eat less and exercise more.
When the diet does not provide the calories needed to produce the energy being spent, the body uses stores of fat and muscle to make energy. However, when muscles are used for energy it reduces their size and strength. For example, even the heart muscle can be a source of energy, but the consequence of using heart tissue for fuel would be a weaker heart and a lower exercise capacity. Full article