A lot of attention has focused lately on how heavy Americans are becoming. In fact, almost 70% of Americans are overweight or obese, putting them at greater risk for cardiovascular disease, stroke, cancer, and diabetes.
Women with more than 32% body fat and men with more than 25% body fat are obese. To measure body fat, health professionals use a variety of methods, including underwater weighing, skin-fold calipers, bioelectrical impedance, dual energy X-ray absorptiometry (DEXA), and air displacement using a device called the Bod Pod. The most accurate methods are underwater weighing and DEXA, but these methods may not be easily accessible for all people. Calipers and bioelectrical impedance machines are widely used by fitness centers and weight-loss programs, but they may not be as accurate.
It's important to note that it's not just how much extra body fat a person has, but where it is stored on the body that determines how risky the extra pounds are. People who are apple-shaped carry their excess fat mostly around the waist. This type of obesity consists of a different type of fat, associated with severe disorders of metabolism. These people who are apple-shaped and obese are much more likely to develop serious health problems than people who are pear-shaped and carry extra fat mostly in the hips and thighs. People who are pear shaped have a type that does not lead to severe metabolic abnormalities, like diabetes, heart disease, or high blood pressure. Overweight and obese conditions, however, regardless of fat distribution, markedly increase risk for disease and increased mortality when compared with people of optimal weight.
Scientists refer to having an apple shape as "central obesity." Its characteristic potbelly indicates that the internal organs are surrounded by fat, which poses a high risk for obesity-related diseases. Waist circumference is an indication of central obesity. A woman's waist should be less than 36 inches around and a man's less than 40 inches.
Central obesity can be a sign of a condition called metabolic syndrome. People with metabolic syndrome may have elevated blood pressure, high triglycerides, insulin resistance, and low levels of HDL ("good") cholesterol. This combination of factors creates an especially high risk for stroke, cardiovascular disease, and diabetes.
In addition to waist circumference, calculating body mass index (BMI) is a simple way to determine if body fat is in the healthy range. BMI is based on height and weight and correlates well with body fat level. A healthy BMI is between 18.5 and 24.9. A BMI of 25 to 29.9 is considered overweight, and 30 or greater is considered obese. To calculate BMI online, visit the CDC website. People who know they would benefit by losing weight should cut calories, keep portions small, and exercise. Lifestyle changes aren't always easy, but without action, people with excessive body fat face a future of poor health.