Why is abdominal fat bad?

DEAR DOCTOR K:

Why is abdominal fat worse for your health than fat around the hips and thighs?

DEAR READER:

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. (See illustration.) Ideally, waist circumference should be less than 35 inches for women and less than 40 inches for men.

Gut check

A tape measure is your best home option for keeping tabs on visceral fat. Measure your waistline at the level of the navel — not at the narrowest part of the torso — and always measure in the same place. (According to official guidelines, the bottom of the tape measure should be level with the top of the right hip bone, or ilium — see the illustration — at the point where the ilium intersects a line dropped vertically from the center of the armpit.) Don’t suck in your gut or pull the tape tight enough to compress the area. In women, a waist circumference of 35 inches or larger is generally considered a sign of excess visceral fat, but that may not apply if your overall body size is large. For men, a waist circumference of 40 inches or more indicates excess visceral fat. Rather than focus on a single reading or absolute cut-off, keep an eye on whether your waist is growing (are your pants getting snug at the waist?). That should give you a good idea of whether you’re gaining unhealthy visceral fat.

Illustration of how to measure waistline

 

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.