Technically, belly fat is any fat tissue that lies between your breastbone and your pelvis. While excess fat in this region of the body has been linked to a greater rate of heart disease, diabetes, and metabolic syndrome -- as well as poorer longevity in general -- the dangers associated with belly fat seem more serious, depending on where exactly the fat lies.
Subcutaneous Fat: Fat in the abdomen sits either outside of, or within, the abdominal muscle wall. Fat that lies between the skin and the abdominal muscle is called subcutaneous fat. It's the fat you can see (if you have some extra), and easily pinch, whether you're standing or lying down.
Visceral Fat: Visceral fat is the second type of belly fat, and it's less visible because it resides within the abdominal cavity. It's necessary as an energy reserve, and for the maintenance of a proper core body temperature. Too much visceral fat is believed to be dangerous, however, because it appears to interfere with the body's ability to metabolize insulin, which can lead to high blood pressure, high triglyceride levels, and other serious problems.
Since a simple reading of body weight in pounds or kilograms doesn't reveal whether excess fat is of the dangerous belly variety, researchers have come up with a calculation called the waist-to-hip ratio. It compares the circumference of your waist measurement with that of your hips, and is considered a more accurate predictor of metabolic risk than either body weight, or Body Mass Index (BMI). Our Heart Disease guide Dr. Richard Fogoros describes the value of waist-to-hip ratios in this article.
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