BMI, a 'flawed' measure of health

In what could be the death knell for that once-vaunted measure of health known as Body Mass Index (BMI), a new study has revealed that it incorrectly categorizes millions of "obese" people as unhealthy.

The study led by UCLA psychologists has found that using BMI to gauge health incorrectly labels more than 54 million Americans as "unhealthy," even though they are not.

Lead author A. Janet Tomiyama said that many people see obesity as a death sentence, but the data show there are tens of millions of people who are overweight and obese and are perfectly healthy.

The scientists analyzed the link between BMI, which is calculated by dividing a person's weight in kilograms by the square of the person's height in meters and several health markers, including blood pressure and glucose, cholesterol and triglyceride levels, using data from the most recent National Health and Nutrition Examination Survey.

The study found that more than 30 percent of those with BMIs in the "normal" range, about 20.7 million people, are actually unhealthy based on their other health data; more than 2 million people who are considered "very obese" by virtue of having a BMI of 35 or higher are actually healthy.

Tomiyama noted that there are healthy people who could be penalized based on a faulty health measure, while the unhealthy people of normal weight will fly under the radar and won't get charged more for their health insurance. Employers, policy makers and insurance companies should focus on actual health markers.

Co-author Jeffrey Hunger said the research shows that BMI is a deeply flawed measure of health, adding that this should be the final nail in the coffin for BMI.

The study appears in International Journal of Obesity.