There's a saying about what matters in real estate: location, location, location. The same holds true for your personal real estate. When you look in a mirror, where do you see extra pounds?

Weighing too much is harmful, but the location of those extra pounds can worsen the risk. Simply put, extra weight around your middle puts you at greater risk for heart disease.

"For both men and women, abdominal fat carries the greatest health risk," says James M. Rippe, M.D., associate professor of medicine at Tufts University School of Medicine and author of 26 health and fitness books, including The Healthy Heart for Dummies. He says the so-called apple-shaped body is more dangerous because abdominal fat cells cause greater metabolic changes. Those changes can include insulin resistance (a forerunner of diabetes) and a faster heartbeat.

The body mass index (BMI) has become the standard way to learn the healthy weight for your height. In general, BMI can accurately determine if you are of normal weight, or if you are overweight or obese, but the calculation is not perfect. If you are very muscular but with little body fat, for example, your BMI may wrongly indicate that you are overweight or obese. Other people might have a normal BMI, but still have excess body fat.

Dr. Rippe says there's a less technical way to find out if you're too fat, and it's backed by a study he co-authored in a supplement to the journal Obesity Research. "Waist circumference is the best predictor of risk for heart disease," he says.

Here's all you need to learn your waist circumference: a plastic tape measure and a half-naked body. "It's an easy measurement to take, but less than 1 percent of doctors take it," Dr. Rippe laments.

Regardless of height, if your waist measures more than 37 inches for a man and more than 31.5 inches for a woman, it's time to think about a weight-loss program, Dr. Rippe says. "You don't have to wait for it to get to that point," he adds. "The higher the numbers, the greater the risk. There's no free pass if it's slightly under."

Measuring your waist

• Place a plastic tape measure around your waist. That's not where you wear your belt -- your actual waist falls an inch or two below the navel for most people.

• Stand normally. Don't suck in your gut.

• Measure the largest circle around your body between your belly button and your hips.

If your waist is more than 37 inches for a man or more than 31.5 inches for a woman, ask your doctor about weight loss options.