Ask Dr. K: Lose abdominal fat with smart food choices

The more visceral fat you have, the greater your risk of developing insulin resistance. This condition can lead to Type 2 diabetes and to an increased risk for cardiovascular disease. In women, it is also associated with a higher risk of breast cancer. (I’ve put on my website, AskDoctorK.com, an illustration showing where in the body visceral and subcutaneous fat are located.)

It requires expensive imaging techniques to measure the amount of visceral fat you have. But you can estimate your visceral fat by measuring your waist circumference. Ideally, waist circumference should be less than 35 inches for women and less than 40 inches for men.

Fortunately, visceral fat is likely to shrink when you lose weight. Here are a few tips for banishing this unhealthy type of fat:

— Limit candy, cookies and white bread. Sugar and refined carbohydrates create a spike in blood sugar, which is answered with a burst of the hormone insulin. This stimulates the production of visceral fat.

— Trim portion sizes. Serve dinner on a salad plate. At a restaurant, ask for half of your entree in a “to go” bag even before your meal is brought to the table, or split one entree with someone. That’s what my wife and I do almost always (but not on special occasions, and especially not at Thanksgiving!).

— Retool your diet. Emphasize fruits, vegetables, whole grains and lean protein. These foods not only are generally good for your health, they are also less likely to build up visceral fat than “bad carbs” (refined carbohydrates) and “bad fats.”

— Avoid “bad fats.” Switching to healthier fats won’t help you lose weight, but it will help lower your heart disease risk. Avoid saturated fats (found in meats and butter) and trans fats (found in fried foods and baked goods). Choose monounsaturated and polyunsaturated fats found in fish, nuts and certain oils (olive, canola, flaxseed).

— Stay active. Commit to 30 minutes of moderate-intensity aerobic exercise on most days, plus resistance exercise a few days a week. (Sit-ups tighten abdominal muscles, but they won’t decrease visceral fat.)

In addition to the distinction between visceral fat and subcutaneous fat, another distinction has become potentially important: the difference between white fat and brown fat. Some of you have asked about it, and I’m going to devote a column to it soon. White fat stores calories, whereas brown fat burns calories. Many research teams are working on ways to give us more brown fat, to help us keep a healthy weight.

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.