Women who lift weights just twice a week for an hour can fight middle-age spread, that buildup of tummy fat that seems to take hold--and rarely let go--as we age, reports The Associated Press of new research from the University of Pennsylvania School of Medicine.

Best of all, they flattened their tummies without dieting. This is more than an issue of vanity. The kind of fat that weightlifting fights is that deep, intra-abdominal fat that wraps around internal organs and is linked to heart disease.

Belly fat is also the No. 1 complaint of women as they go through menopause. "It's the apple-shaped person I'm most worried about," Dr. Tracy Stevens, a cardiologist who directs the women's heart center at St. Luke's Hospital in Kansas City and was not involved in this study, told Reuters. "The more central the fat, the more it's laid down in the arteries."

The study: More than 160 overweight and obese women between the ages of 24 and 44 were divided into two groups. One group participated in a two-year weight-training program using both free weights and machines with a focus on the chest, back, shoulders, biceps, triceps, lower back, buttocks and thighs. The other group was given a brochure that recommended they exercise 30 minutes to 60 minutes a day most days of the week. Neither group was asked to change their diets in a way that would lead to weight loss, reports Reuters.

The results: Those who lifted weights for two years experienced a 7 percent increase in intra-abdominal fat, compared with a 21 percent increase among the group that was given exercise advice. Even more encouraging, the weightlifters decreased their body fat percentage by almost 4 percent, while the other group remained about the same.

The downside? Unlike walking or running on a treadmill, this is not something you can do in your basement unless you can afford to install a full gym.

--Cathryn Conroy