Two University of Pennsylvania (UPenn) researchers want a better alternative to body mass index (BMI) because they said it is not accurate enough, the Los Angeles Times reported.
BMI has been a staple in determining health risks since a Belgian mathematician named Adolphe Quetelet invented the formula in 1832. Its simple premise makes it easy for anyone to calculate it with just a scale and a ruler.
All one must is divide their weight in kilograms by their height in meters squared. Any number over 30, the line of obesity, has statistically proven to increase one's chance of Type 2 diabetes, cardiovascular disease and some cancers.
"Most studies depend on BMI, and we know it's not a very accurate measure," study co-author Dr. Rexford Ahima, a medical professor at UPenn, in Philadelphia, told Live Science.
The study, published in the journal Science, said BMI does not take into account any other factors, like chronic illness. The researchers said a person with a higher BMI is more likely to survive a serious health risk because the added fat can provide energy reserves.
The conflict of study results in the health risks of obesity have prompted "a lot of sniping back and forth between different groups of researchers," Ahima said.
The researchers said BMI does not take into account where someone's fat is distributed in their body, which is important in determining risk of certain illnesses. Belly fat is more of a risk to cardiovascular disease and diabetes, but peripheral fat is more harmless, some studies suggest.
BMI also does not take race, gender or age into account, but Ahima said so many people use it because it is a simple measure. It is also unfair to athletes who gain weight with muscle and the elderly who can lose height.
Ahima said obesity is too complex of a condition to measure with one number and a formula. He said it is about starting weight, gender, genetics and other factors.
"What is it about being obese that makes one unhealthy or healthy?" Ahima said. "We need to understand the molecular mechanisms."
