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How Do Hormones Affect Body Fat?

Posting Date: 06/01/2000

Q: I recently had a hysterectomy -- and did that ever change my body! I used to be 22 percent fat, and now I can't get it any lower than 28 percent. I'm very diligent about my diet (I keep it at 20-25 percent fat). I've even increased my exercise from 30 minutes to 45 minutes a day. Help!

A: You didn't say in your letter, but I suspect you are now taking some kind of hormone replacement drug. A five to ten percent increase in body fat is almost inevitable with these drugs. Female hormones increase body fat. This is why we say healthy women are allowed to be 22 percent fat, while men must shoot for 15 percent. If a man takes female hormones (as protection against a second heart attack, for instance), his body fat increases. Women using birth control pills also have about two or three percent more fat than when they are not taking them.

Women who are postmenopausal, either naturally or from a hysterectomy, face another problem if they choose not to use hormone replacement therapy. The lack of estrogen augments bone loss. They don't gain fat, but they lose lean mass. This, too, gives a high body fat reading. (The ratio of fat to lean increases, giving a higher percentage of fat even though the actual pounds of fat may be unchanged.)

In any case, since you exercise a lot and watch your diet carefully, please don't try to get back down to 22 percent fat. Accept 28 percent as normal for you, being sure to test yourself occasionally to stay on track.

Adapted from The New Fit or Fat by Covert Bailey. Copyright 1977, 1978, 1991 by Covert Bailey, published by Houghton Mifflin Company. All rights reserved.