Updated

If you do just one thing to fight fat, exercise might be the way to go, judging by a new study.

Consider the study’s results:

—Inactivity led to a buildup of fat deep inside the belly.

—Modest amounts of exercise held the line on deep belly fat.

—Higher amounts of exercise cut deep belly fat and fat around the waist.

The study appears in The Journal of Physiology. It took place at Duke University under the supervision of exercise physiologist Cris Slentz, PhD, and colleagues.

Mindset Shift

If Slentz had it her way, people would quit thinking “weight loss” and start thinking “health gain.”

“Until we are able to prevent the weight that many dieters regain following short-term success, we should place a greater national emphasis towards prevention,” says Slentz in a news release.

“It will be a challenge to change the message from ‘exercise now to lose weight’ to ‘exercise now so in five years you won’t be 20 pounds heavier,’” she continues.

‘Hidden’ Fat

If deep belly fat is hidden, why does it matter? The stakes may be too high for an out-of-sight, out-of-mind outlook.

Deep belly fat (technically called “visceral fat” or fat surrounding organs within the abdomen) has been linked to health problems including heart disease, type 2 diabetes, and metabolic syndrome — a cluster of risk factors that greatly increase the chance of developing these diseases.

Visceral fat hasn’t been proven to cause those conditions, but it seems to at least be a red flag of possible health risks, write Slentz and colleagues.

By the way, visceral fat isn’t just for the millions of overweight or obese people. Thin people can also have visceral fat if they’re not fit.

How Do You Compare?

Slentz’s study included 175 men and women in North Carolina. See how you compare to them:

—All were overweight, inactive, and had mild-to-moderate cholesterol problems.

—They were 40-65 years old.

—The women were postmenopausal.

—None had diabetes, high blood pressure, or plans to diet.

—Nearly 20 percent were minorities.

Now, consider what participants agreed to do for six months:

—Stay sedentary (the comparison group)

—Get low amounts of moderate-intensity exercise (equal to walking 12 miles weekly)

—Get low amounts of vigorous-intensity exercise (equal to jogging 12 miles weekly)

—Get high amounts of vigorous-intensity exercise (equal to jogging 20 miles weekly)

Participants used treadmills, stationary bikes, and elliptical trainers. They were directly supervised or wore heart-rate monitors to check their workout intensity.

They were also counseled not to diet or change their diet during the study.

Blasting Belly Fat

Before-and-after imaging scans of the belly were done to check visceral fat. The results:

—Visceral fat rose by nearly 9 percent in the idle group.

—Visceral fat didn’t change with low amounts of exercise (at either intensity).

—Visceral fat dropped 7 percent, on average, in people who got a lot of vigorous exercise.

The group that got the most vigorous exercise also had a 7 percent drop in fat around their waistlines. They were the only group that lost fat.

Double-Sided Findings

On one hand, the study shows the high price of inactivity, states Slentz.

Then again, it also shows that people with some extra pounds and no exercise habits can change their ways and reap the rewards.

Modest exercisers logged the equivalent of 11 miles per week. They matched current recommendations from the CDC and American College of Sports Medicine, the researchers note.

Those who got the most exercise did the equivalent of jogging 17 miles weekly. “While this may seem like a lot of exercise, our previously sedentary and overweight subjects were quite capable of doing this amount,” says Slentz.

Think Balance

”I don’t believe that people in general have gotten lazier,” says Slentz. “It’s more that they are working too hard or are at their desks working on computers with fewer opportunities to exercise. The situation is out of balance.”

The name of the game is regaining that balance by getting more exercise, the study shows.

Consult your doctor before starting a new exercise program.

By Miranda Hitti, reviewed by Brunilda Nazario, MD

SOURCES: Slentz, C. Journal of Applied Physiology, October 2005. News release, Duke University Medical Center.