Around age 35, a dip in estrogen sounds an alarm to a woman's fat cells. These 30 billion cells, in turn, swell in size, number, and ability to store fat so they can assume the duty of pumping estrogen once her ovaries cease this role during menopause.
What does this mean to you? The fat cells at your waist grow the largest because they're better equipped to produce estrogen than fat cells elsewhere in your body. As a result, pounds may seem to amass around your middle without any appreciable change in your eating habits or exercise routine.
The good news is that the larger and more active your abdominal fat cells become, the more estrogen will be produced -- and the more benefits you'll receive as you enter menopause: fewer hot flashes, milder mood swings, reduced memory loss, improved sleep, less intense PMS, and a lower risk of getting osteoporosis.
Women also add pounds because a middle-aged body doesn't have the energy it had as a teenager. In the stage before menopause, metabolism (the energy furnace that burns calories) slows 10 to 15 percent, says Debra Waterhouse, a registered dietitian and author of the book, Outsmarting the Midlife Fat Cell.
"It's in our biological blueprint," she says. "Your body is programmed in the decade before menopause to add weight and expand at the waist."
But it need not rule or destroy you. You can have some control -- the difference between gaining a few pounds or increasing a few dress sizes. Here are some tips -- on the pages that follow -- from Waterhouse, who has been able to keep a lid on not only her own weight gain but also that of many of her clients.