More women than men experience an increase in this type of fat, especially in the time following menopause. It is often responsible for the change in a woman’s body to an apple shape. In men, it may manifest itself as a “beer belly.”

Sometimes referred to as abdominal obesity, this fat is more dangerous than the subcutaneous fat that lies just under the skin. Fat cells produce hormones, including ones that can cause insulin resistance and type-2 diabetes. Visceral fat is also thought to increase the risk of heart disease, metabolic problems, and high blood pressure. It has also been linked to breast cancer.

It is quite possible for a person with a healthy weight and relatively trim waistline to have significant amounts of visceral fat. It can be hard to see because of where it lies; in some cases it can only be detected with an MRI.

According to the Mayo Clinic, lack of exercise and low metabolism isn’t necessarily the culprit. The problem, they say, may be genetics. If your family has a history of gaining weight around the middle, it may be a challenge for you, too. In women, hormonal changes during menopause also may cause a change in how fat is broken down and stored.

Rather than calculating your BMI, Mayo Clinic suggests simply measuring your waistline. A waist measurement of 35 inches or more, the clinic says, indicates an unhealthy concentration of abdominal fat.

One of the best things you can do for your body is exercise regularly, and, luckily, visceral fat responds well to working out. Daily moderate exercise along with strength training may be your best bet to battling the bulge.