The Body Mass Index, much like counting calories, waist training and diet pills, has long been a highly contested fad in diet culture. Now it seems the science community has officially scrapped it as a method of measuring health, after new research found that almost half of people diagnosed as obese using BMI measurements are actually healthy.
The study, conducted by UCLA psychologists and published in the International Journal of Obesity, found that nearly half of Americans considered to be overweight – 34.4 million people – are actually “perfectly healthy”, as are 19.8 million people who are considered “obese.”
Typically, someone with a BMI below 18.5 is regarded as underweight, 25 or over as overweight, and 30 or more as obese. The index is reached by dividing weight (in kilograms) by height (in meters), and dividing the answer by height again.
For years it's been considered a direct indicator of a person’s health, used by life insurance companies to determine a person's eligibility, but the researchers analyzed the link between BMI and a number of other health markers, such as blood pressure, insulin resistance and cholesterol levels. Their conclusion: the index is misleading.
Janet Tomiyama, the study’s lead author, said in a press release:
"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."
Conversely, the paper found that 20% of Americans with “normal” BMI range were actually unhealthy once other health factors were taken into account.
With obesity levels constantly growing, the concern is that BMI is not an accurate predictor of future health. People can be at risk of diseases and health issues and still have a normal BMI, which gives them false hope.
While this may seem like trivial science news, it's actually a pretty big deal. The body-positive community has been making strides recently, with body diversity being slowly accepted, and this news is a sort of seal of approval from the science community.
As fat-shaming and body image disorders run rampant, especially in young girls, it's crucial to re-write the rules that dictate what is healthy and what isn't, and this news is a first step in the right direction.
Jeffrey Hunger, a co-author of the paper, declared “This should be the final nail in the coffin for BMI.”