Hormones from fat cells cause damage throughout our bodies
DEAR DOCTOR K:
Why is abdominal fat worse for your health than fat around the hips and thighs?
When it comes to body fat, location counts. Fat above the waist (the "apple" shape) is much more dangerous than fat in the butt and thighs (the "pear" shape).
In most people, about 90 percent of body fat lies in a layer just beneath the skin. The remaining 10 percent -- called visceral fat -- lies out of reach, deep within your abdomen. It's found in the spaces surrounding your liver, intestines and other organs. It's also stored in a flap of tissue that lies under your stomach muscles.
Visceral fat is a key player in a variety of health problems, including cardiovascular disease, dementia, asthma, and breast and colorectal cancer.
What makes visceral fat so dangerous? Research over the past 20 years has completely changed our understanding of what fat is. We've always known that fat is composed of billions of cells called fat cells. We used to think that fat was just a layer of insulation to keep heat inside our bodies during cold weather. We didn't think that fat, and fat cells, really did anything more than provide insulation.
However, we've discovered that fat cells -- particularly fat cells inside the abdomen (visceral fat)-- are little hormone factories. They are constantly producing substances that get into the blood and travel to other parts of the body, where they can have profound effects.
For example, some of the hormones produced by fat cells affect your appetite, your metabolism, even your blood pressure. Researchers at Harvard have discovered that visceral fat secretes a molecule that increases insulin resistance (raising the risk of Type 2 diabetes). In addition, visceral fat cells make certain proteins that trigger low-level inflammation. This is a risk factor for heart disease.
You can estimate your visceral fat by measuring your waist circumference. (I've put an illustration explaining how to do this on my website, AskDoctorK.com.) Ideally, waist circumference should be less than 35 inches for women and less than 40 inches for men.
To keep visceral fat at bay:
-- Keep moving. Exercise can help you reduce your waist circumference, lose visceral fat and gain muscle mass. Engage in at least 30 minutes of moderate-intensity activity most days.
-- Eat right. Choose a balanced diet that helps you achieve and maintain a healthy weight. Avoid products that encourage belly fat, including trans fats and fructose-sweetened foods and beverages.
-- Don't smoke. The more you smoke, the more likely you are to store fat in your abdomen rather than on your hips and thighs.
-- Forget the quick fix. Liposuction doesn't reach inside the abdominal wall to your visceral fat. You may change your appearance with liposuction, but you won't improve your health.
(Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.)
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