Body mass index a flawed measurement, US scientists say

By Barry Eitel

SAN FRANCISCO

An equation for diagnosing obesity commonly used by doctors for decades is actually a flawed measure, according to new research released Friday by scientists.

Body mass index (BMI) is a simple method used by doctors to decide if a patient is overweight by comparing a weight to height ratio.

But millions of Americans who would be considered overweight or obese by BMI are, in fact, “perfectly healthy” claims the new research conducted by scientists at the University of California Santa Barbara and the University of California Los Angeles.

The report find that 34 million Americans considered overweight by BMI standards are healthy, as are another 20 million considered obese by virtue of their BMI. “In the overweight BMI category, 47 percent are perfectly healthy,” Jeffrey Hunger, co-author of the study, said in a statement.

“So to be using BMI as a health proxy – particularly for everyone within that category – is simply incorrect. Our study should be the final nail in the coffin for BMI.”

Most doctors and experts believe obesity has ballooned into a massive global health crisis, although much of the statistics use BMI as a yardstick.

The World Health Organization reported last year that worldwide obesity has more than doubled since 1980, and that nearly 2 billion adults are considered overweight by BMI, including approximately 600 million who are considered obese.

The new analyzed BMI statistics alongside health markers such as blood pressure, cholesterol levels and blood sugar. Researchers found BMI to be a poor indicator of a person’s overall health, even though it is still often used by government agencies and health insurance companies, for example.

“Not only does BMI mislabel 54 million heavier individuals as unhealthy, it actually overlooks a large group of individuals considered to have a 'healthy' BMI who are actually unhealthy when you look at underlying clinical indicators,” Hunger continued.

The findings were published in the International Journal of Obesity.