Metabolism — your body’s “fat burner” — can be your greatest ally…or your worst enemy. If you’re an on-again, off-again dieter, you could be making yourself fat.
“Most people lose lean mass (primarily muscle and water) as well as fat when they lose weight. This is especially true if they ‘diet’ by cutting calories and don’t exercise,” says Michael J. Hewitt, Ph.D., director of exercise physiology at Canyon Ranch in Tucson. “When the weight comes back, most of it is fat. With each loss/gain cycle, the percentage of lean mass decreases and the percentage of fat increases, which slows metabolism.”
Why the slump? Because for every pound of fat you gain, your body burns a measly two calories a day at rest compared to an average of 50 calories for each pound of muscle. So if you lost five pounds of muscle on the latest “starve-yourself-get-slim-quick diet,” only to regain it as fat, you’re burning 240 fewer calories a day.