Adding a few pounds around the midsection during adulthood seems innocuous enough. It has its own catchy moniker ? middle-age spread ? and was once a sign of prosperity and success. Today it's a sign of trouble. Abdominal fat, also called visceral fat, contributes more to health problems such as heart disease and diabetes than fat around the hips and thighs.

A study in the July 2007 Diabetes Care showed that men and women whose waists spread over a nine-year period had corresponding increases in the metabolic syndrome. This constellation of risk factors ? high blood pressure, resistance to insulin, and worrisome cholesterol levels ? seriously increases the chances of developing heart disease and diabetes. A six-year study of nearly 73,000 women in China, published in the spring of 2007 in the Archives of Internal Medicine, shows that those with larger waists were more likely to die prematurely than those with smaller waists.

Measuring your waist offers useful information you can't get from stepping on the scale. Many people lose muscle and add abdominal fat as they go through midlife, and such changes may not affect weight. An expanding waistline, though, can warn of trouble brewing inside the body. National guidelines sound warnings when waist circumference is greater than 40 inches for a man or 35 inches for a woman.

Your waist circumference isn't your belt size. To measure your waist, wrap a flexible measuring tape around your abdomen where the sides of your waist are narrowest. This is usually even with your navel.

Use your waist as a kind of low-tech biofeedback device: A waistwise expansion over the years should be a wake-up call to re-evaluate your diet and physical activity level.

Smart diet and exercise choices may make the difference in your middle:

FOOD AB-FLATTENERS

Reduce animal fats and trans fats. Those who eat too much saturated and trans fats are more likely to overeat and be insulin resistant, have higher cholesterol and a larger waist size. So eat more fish than poultry or meats, and choose low-fat dairy. And eat plenty of fruit and vegetables, beans and whole grains.

Avoid alcohol. They don't call it a beer belly for nothing. Alcohol may be more likely to increase ab fat, possibly due to the effects of the alcohol, or possibly because every drink is an infusion of 200 to 400 calories (the equivalent of one to two candy bars), so several nights out a week can really add up.

Eat good carbs. Minimize eating processed, refined carbs like white bread, bagels, muffins, pasta, cookies and cakes; they are linked to larger waistlines. Eat whole grains (that means cooked brown rice, barley, quinoa and the like.) When that's not practical, choose the least processed versions of foods and try to enhance them. So, choose whole wheat pasta and sprinkle quinoa in the boiling pot, or choose whole grain (not just ?brown?) bread and add a layer of uncooked oatmeal to the fillings inside (you won't taste it but it will add fiber, nutrients and more chew to your sandwich or toast).

FITNESS AB-FLATTENERS

Do cardio nearly every day. Regular exercise will help you lose more deep abdominal fat, and cardio seems to work best since it burns the most calories per minute.

Work out at higher intensities. Get your heart rate up higher. One study at Duke University in Durham, N.C. found that 175 overweight men and women who walked at least 11 miles per week prevented increases in their ab fat over eight months. (So, about 45 minutes, four days per week.) But those who worked harder (walking fast or jogging) for 20 miles a week (about 60 minutes, five days a week) actually lost ab fat?and this was all without dieting!

Accumulate 60 to 90 minutes a day (or aim for that). Start walking or doing other types of cardio as much as you can. If you're a new exerciser, build up fitness first with 15 minutes of brisk walking or cardio activity every day and add more minutes every week. Work up to doing 60 to 90 minutes on most days of the week