Is weight gain as you pass through middle age and later inevitable? After all, hormonal changes from menopause land a one-two punch—boosting fat accumulation while simultaneously making it harder to hang on to calorie-burning muscle. The result is often increased weight, especially belly fat—aka, the “menopot.” It’s even worse if weight issues run in your family genes.

But you can triumph over your genes when it comes to this weight gain and without eating so little that you feel you’re starving, according to new research published in Menopause. The secret might not sound surprising at first—it’s exercise—but not just any kind of exercise. And you don’t have to exercise every day. It turns out that getting enough exercise each week…of the right kind…is so powerful that it can override a genetic predisposition to putting on pounds.

It may even get easier as you get older.

This Exercise Knocks Out Genetics

The researchers developed a genetic risk score based on 95 variants in the building blocks of DNA and used it on data from 8,206 women, ages 50 to 81, from the Women’s Health Initiative, an ongoing study of postmenopausal women. The goal was to examine the effect of obesity genes on body mass index (BMI)—a measure of body fat based on weight in relation to height—later in women’s lives and to see to what extent lifestyle behaviors, including exercise, might mitigate that effect. Past studies have suggested that genetics play a role in ratcheting up BMI, but not much was known about the interplay of genetics and weight as people age—or how lifestyle might influence that interplay.

Many of the findings weren’t surprising. After controlling for various lifestyle factors, the researchers found, as they expected, that women who exercised the most had the lowest BMIs, regardless of their age. Women who got a “moderate” amount of exercise—basically, met the minimum recommendation of getting 150 minutes per week of moderate-intensity aerobic activity (such as walking at three miles per hour) or 75 minutes of vigorous-intensity exercise (running, doing activities that make you break a sweat)—weighed less compared with those who got little or no exercise.

Women who exceeded those minimum recommendations—getting about 20% more exercise weekly than the minimum—did even better. These “high” exercisers weighed, on average, about nine pounds less than their sedentary peers. Exercise partly overcame genetic risk. When the researchers looked more closely at the genetic markers for obesity, they found that physical activity reduced the impact of a woman’s genetic predisposition to obesity.

But the real surprise was that the genetic risk dropped the most in the oldest age group—women 70-plus. Exercise habits were more strongly linked with lower BMI in women in their 70s than those in their 60s or 50s. Chalk it up as an unexpected benefit of aging—and of the importance of physical activity at any age.

If you, your mom or your grandmother is postmenopausal, keep in mind that staying active will improve your health in myriad ways such as preventing muscle loss…improving bone strength…balance… mood…concentration…keeping your brain healthy—and now, curbing any genetic tendency you might have toward being overweight.

Looking for ways to lose weight? See the Bottom Line article “9 Ways to Lose the Last 10 Pounds.”