Slowing metabolism when I hit 30?

Originally Published: September 11, 2009 - Last Updated / Reviewed On: January 24, 2014
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Hi Alice,

I'm a 22 year old woman. Many of my friends in their late 20s and early 30s (and older) have been warning me about an inevitable metabolism slow-down and subsequent weight gain around my 30th birthday. They say, "You just wait. When I was your age, I sat around all day eating pizza and I never gained a pound. Now I can't lose weight no matter what I do."

I am sure there's some truth to this, but I DON'T sit around eating pizza all day. I run three to four times a week and eat very healthfully. Will these habits ease the slowing down of my metabolism? Or should I expect some weight gain no matter what I do (as they say will happen)?

Thanks!

—Slim 'n healthy, and wants to stay that way

Dear Slim 'n healthy, and wants to stay that way,

Like a vintage wine, people gain a variety of finer qualities with age… maturity, wisdom, and possibly grandchildren, to name a few. Physical signs of aging like wrinkles or aches and pains may be less welcome, so it's understandable that you are put off by the idea of putting on some extra pounds. While you can't stop the aging process altogether, maintaining your healthy diet and exercise habits will help you preserve your slim physique.

Gaining weight after your twenties is not inevitable, but many women (and men) do see the scale tilt upwards as they move into later adulthood. A variety of factors may contribute to age-related weight gain including changes in body composition, hormonal fluctuations, genetics, and exercise and nutrition habits. As your friends warn, it's true that metabolism slows as we get older. The aging process depletes muscle while increasing fat deposits. Fat burns fewer calories than muscle, so as your body's proportion of muscle shrinks your metabolism slows down. In the older years, fat tends to accumulate around the midsection, which poses more health risks than, say, thick thighs.

Women feel the effects of this body mass transition more so than men. To begin with, women tend to have less muscle mass than men. Age-related weight gain may also be linked to menopause. Some researchers posit that the hormonal shifts that accompany the change of life affect the way the body breaks down and stores fat, leading to weight gain. Generally, this weight increase begins in perimenopause, a pre-cursor to menopause lasting two to eight years. On average, women gain a pound a year during perimenopause. These pounds can be more difficult to lose compared to weight that might have been gained earlier in life.

A third explanation for weight gain as you age is genetics. Due to genes, some people are simply pre-disposed to be wispy or wide. Your relatives may offer some clues as to what's in store for you. For example, if your family is on the thin side, you may have inherited a tendency to be slender as well. On the other hand, if your clan is a bit hefty, that doesn't necessarily mean you will balloon up after your thirtieth birthday. Weight gain triggered by menopause usually appears after age 40, giving you at least another two decades before extra pounds may emerge.

Although many sources of weight gain are out of your control, one cause — excess calories — is possible to keep in check. If the number of calories you consume is greater the number you burn, weight gain will probably result. Eat too much, and your body stores the energy as fat. Exercise, and the body burns fat for fuel. One way to stay trim is to keep up your healthy eating and exercise habits. Keep in mind that you will need to adjust these habits as you age. Older folks generally need fewer calories due to their decreased muscle mass and lower activity levels. However, many people continue to eat the same amount resulting in a calorie surplus and weight gain.

Continuing to exercise regularly and eat well is the best way to stay healthy overall. However, you can't stop the clock, and it's also good to have reasonable expectations about growing older, even if that means adding a few pounds. Here's to building healthy habits for life!

Alice