Body Mass Index may not be the best indicator of obesity or the most effective measurement of metabolic health because it makes too many generalizations, said Dr. Manisha Chandalia, assistant professor of internal medicine at UT South-western Medical Center.

"When we focus on obesity as an expression of fat mass, we are not taking into account a large body of literature that supports the notion that not all fat people are created equal," Dr. Chandalia told colleagues at her recent grand rounds, Metabolic Complications of Obesity: Inflated or Inflamed.

Dr. Chandalia recommends physicians focus less on the amount of fat a person has and pay more attention to adiposopathy, or sick fat, and its affect on the rest of the body. This is important because anyone who is unfit, has an unhealthy diet and makes poor lifestyle choices can develop adiposopathy.

BMI, which determines obesity by comparing body weight and height ratios, does not evaluate other factors important to metabolic health such as a person's fitness level, amount and location of fat, or risks for developing diseases linked to obesity.

As a result, Dr. Chandalia said physically-fit people with little unhealthy body fat are lumped into overweight and obese categories, undermining warnings to the public about obesity and its risks. For example, celebrities such as Michael Jordan and Will Smith are considered overweight based on BMI calculations while Tom Cruise and Mel Gibson are in the obese category, she noted.

On the other hand, many people with "normal" BMIs have adipose tissue dysfunction, or unhealthy fat. They are at risk for obesity-related illness such as diabetes and cardiovascular disease but often go undiagnosed.

"If we, clinicians and scientists, hope to control the epidemic of adipose tissue dysfunction then we must broaden our definition of obesity to adiposopathy," she said. "Our efforts in establishing markers to identify 'at risk' populations and finding newer therapeutic agents must focus on adiposopathy and not on obesity alone."

Dr. Chandalia said an effective tool for identifying people with adiposopathy might be measuring levels of a patient's plasma C-reactive protein (CRP): an inflammatory marker that correlates with type 2 diabetes, cardiovascular disease, waist circumference, LDL-cholesterol and other metabolic disorders.

Studies have shown that people with high CRP levels have a greater risk of diabetes, coronary artery disease, stroke, sudden death and other types of cardiovascular disease. The findings also seem to be consistent for many ethnic groups, while more conventional measuring guidelines do not always apply equally.