BMI of Obesity

One third of the American adult population is obese. According to the Centers for Disease Control and Prevention, obesity is defined as having a Body Mass Index---BMI---of 30 or greater. The term obesity refers to excess weight for a given height. This excess weight is associated with increased risk of developing certain diseases. BMI is a measure of the ratio of weight to height that generally correlates with body fat percentage. It can be calculated by dividing weight in kilograms---2.2 lb per kg---by height in meters squared---0.254 m per inch. This condition affects 35.7 percent of non-Hispanic Blacks, 28.7 percent of Hispanics, and 23.7 percent of non-Hispanic whites.

BMI Obesity Class I

The World Health Organization has further classified obesity by breaking down the obese BMI category into three classes. Obese Class I encompasses BMI values between 30 and 34.99. This classification represents an increased risk of developing diseases such as type 2 diabetes mellitus.

BMI Obesity Class II

Obese Class II is classified as those with a BMI between 35 and 39.99. The National Heart, Lung, and Blood Institute at the National Institutes of Health provides a BMI table so you can easily see where you fall without having to do the math. (See Resource) As your BMI increases, your risk of developing disease and disability increases. At a BMI of 35 or greater, bariatric surgery, such as gastric bypass surgery, is advised if all other avenues of weight loss have been pursued and failed.

BMI Obesity Class III

Obese Class III, defined as having a BMI of 40 or above, is considered morbidly obese. People in this class are at immediate risk for life-threatening health problems.

Associated Risks

Obesity is associated with increased risk of developing certain chronic diseases such as cardiovascular disease, arthritis and diabetes. In order to further assess health risks associated with high BMIs, the NHLBI recommends a physical examination by a primary care physician and measurement of waist circumference. High BMI and high waist circumference indicate a higher risk of disease than high BMI and low waist circumference, as the additional measurement takes into account distribution of fat.

Associated Benefits

It may be difficult to see any benefits of a BMI that indicates obesity, but there is a benefit in terms of treatment. Many insurance companies cover bariatric surgery, but include a BMI restriction. Generally, if your BMI falls into obese classes II or III, you may be eligible for coverage of bariatric surgery.