Wednesday, December 17, 2008

The Truth About Belly Fat

The Truth About Belly Fat
What's the best way to trim your tummy?
By Kathleen M. Zelman, MPH, RD, LD


Having a flat belly or so-called "six-pack abs" is a dream of most adults. If you're middle-aged, have ever been pregnant, or sometimes indulge in too much food or one too many beers, you probably have a spare tire you'd like to get rid of. So what's the best strategy for banishing belly fat? Is it as simple as adding certain foods to your diet, or doing particular exercises?

WebMD turned to the experts for answers on belly fat -- and the best ways to lose it.
The Answer to Flatter Abs

Don't despair; you can lose that spare tire, experts say. But there's no secret formula.

"There is no magic bullet, diet plan, specific food, or type of exercise that specifically targets belly fat. But the good news is belly fat is the first kind of fat you tend to lose when you lose weight," says Michael Jensen, MD, a Mayo Clinic endocrinology specialist and obesity researcher.

Whether you're an "apple" shape with excess belly fat, or a "pear" with wide hips and thighs, when you lose weight, you'll most likely lose proportionately more from the abdominal region than elsewhere.

"Ninety-nine percent of people who lose weight will lose it in the abdominal region before anywhere else -- and will lose proportionately more weight from the upper body," says Jensen, also a professor of medicine.

And why is that? "Visceral fat, the kind tucked deep inside your waistline, is more metabolically active and easier to lose than subcutaneous fat under the skin, especially if you have plenty of it," explains Penn State researcher Penny Kris-Etherton, PhD, RD.

And the more weight you have to lose, the more quickly you're likely to start losing your belly fat, experts say.

"People who are significantly overweight may see quicker results in their belly than someone who has less to lose in that area, such as a postmenopausal pouch," says Georgia State University nutrition professor, Christine Rosenbloom, PhD, RD.
Can Whole Grains Help You Lose Belly Fat?

A recent study in the American Journal of Clinical Nutrition showed that a calorie-controlled diet rich in whole grains trimmed extra fat from the waistline of obese subjects.

Study participants who ate all whole grains (in addition to five servings of fruits and vegetables, three servings of low-fat dairy, and two servings of lean meat, fish, or poultry) lost more weight from the abdominal area than another group that ate the same diet, but with all refined grains.

"Eating a diet rich in whole grains while reducing refined carbohydrates changes the glucose and insulin response and makes it easier to mobilize fat stores," says study researcher Penny Kris-Etherton, PhD, RD, a distinguished professor of nutritional sciences at Penn State University.

"Visceral fat is more metabolically active and easier to lose than subcutaneous fat, especially if you have plenty of it and the right conditions are met, such as the ones in our study."
When you eat refined foods like white bread, it triggers a series of events, starting with elevated blood sugar levels followed by an increased insulin response, which can cause fat to be deposited more readily. But eating a diet rich in whole grains (which also tend to be higher in fiber) helps improve insulin sensitivity. This, in turn helps the body more efficiently use blood glucose, lowers blood glucose levels, and reduces fat deposition.

The U.S. Department of Agriculture's 2005 Dietary Guidelines recommends that half of your grain servings come from whole grains.

"Eating whole grains exclusively may be difficult and unrealistic for many people," says Rosenbloom. Instead, she recommends, "work toward consuming more whole grains, as they tend to be high in fiber, which satisfies hunger for longer periods and helps you eat less than refined grains."
Can Monounsaturated Fats Banish Belly Fat?

A recent diet book called The Flat Belly Diet posits the idea that you can lose belly fat by eating a 1,600-calorie diet rich in monounsaturated fats.

Most people will lose weight on a 1,600-calorie diet. And there is little question that when it comes to choosing fats, the monounsaturated fatty acids (MUFAS) found in avocados, nuts, seeds, olives, soybeans, chocolate, olive and canola oils are among the best choices, with proven health benefits, such as reducing the risk of heart disease.

But these are not magic foods capable of targeting belly fat, experts note. While the MUFAS are healthy fats, they are still fats, with nine calories per gram -- more than twice that of carbohydrates and proteins, which have four calories per gram.

"Fats have to be controlled, because it is easy to overeat nuts or guacamole -- which can undo the health benefits by packing on the pounds," cautions Rosenbloom.
Can Exercise Flatten Your Abs?

Hundreds of crunches each day won't flatten your belly if you need to lose weight. If your abdominal muscles aren't covered with excess fat, strengthening them can help you look tighter and thinner. But spot exercises won't banish belly fat.

"If you want to lose weight and keep it off, you must eat a healthy, controlled-calorie diet and get regular exercise -- around 60 minutes a day of moderate activity, like brisk walking," says Rosenbloom.

And the harder you exercise, the more belly fat you may lose. Jensen suggests that people who engage in high-intensity aerobic exercise tend to be leaner around the abdomen.
The Risks of Excess Belly Fat

Why is it important to lose belly fat? Carrying around extra pounds in your midsection is serious business. Extra weight in your midsection is more dangerous than fat around your hips and thighs, as visceral fat is worse for your health than the subcutaneous fat that sits under the skin.

"Extra weight around the midsection is associated with inflammation and a higher risk of health problems such as cardiovascular disease, diabetes, metabolic syndrome and more," Jensen says.

According to a recent study in Circulation, belly fat appears to boost inflammation and is linked to hardening of the arteries.
Is Your Middle Too Big?

Beyond the body mass index (BMI), waist circumference has been touted as a simple and reliable test to measure health, weight status, and hidden fat, says Rosenbloom.

To assess your risk, use a soft tape measure. Lie down and wrap it around your natural waistline, located above your hip bone and below your belly button. Take the measurement without holding your breath or holding your stomach in.

If your waist is larger than 40 inches (for men) or 35 inches (for women), you have too much belly fat and are at risk for heart disease and other conditions. And one of the best things you can do for your health is to lose weight, says Rosenbloom.
The Bottom Line About Belly Fat

So what's the bottom line about belly fat?

Most scientific evidence suggests that a calorie-controlled diet rich in fruits, vegetables, whole grains, low-fat dairy, beans, nuts, seeds, lean meat, fish, eggs, and poultry is the foundation for a diet that provides all the nutrients you need while helping to whittle your waistline.

The real secret to losing belly fat is to lose weight on a balanced, calorie-controlled diet and exercise at least an hour a day.
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View Article Sources Sources

SOURCES:

Penny Kris-Etherton, PhD, RD, distinguished professor of nutritional sciences, Penn State University, State College, Pa.

Christine Rosenbloom, PhD, RD, nutrition professor, Georgia State University, Atlanta.

Michael Jensen, MD, professor of medicine, Mayo Clinic, Rochester, Minn.

Katcher, H.I. American Journal of Clinical Nutrition, January 2008; vol 87: pp 79-90.

WebMD Medical News: "Why Belly Fat Hurts the Heart."

WebMD Medical News: "Whole Grains Fight Belly Fat."
Reviewed on March 04, 2008

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