The BMI Chart is Antiquated and Misleading, Scientists Say
There are better ways to assess health, especially when financial penalties are at stake
The Body Mass Index (BMI) was invented in the 1800’s and became the international standard for weight and health by the 1980’s. Current BMI standards were approved by the National Institutes of Health (NIH) in 1998. But the BMI scale is considered antiquated by many, including doctors, scientists and nutritionists.
A study supports the conclusion that the Body Mass Index is outdated and provides misleading data. This means more than 34 million Americans may have been wrongly told they are either overweight or obese when they are actually healthy individuals.
The BMI is a measure of body fat based on a person’s weight in relation to their height. The index applies to most adults over age 20. For kids, BMI percentile is considered the best valuation of body fat.
According to the chart, the entire roster of the Broncos AFC football team is considered overweight, despite being some of the healthiest men in the world.
“This should be the final nail in the coffin for BMI,” says lead author A. Janet Tomiyama, a psychologist at UCLA.
According to study author Jeffrey Hunger, 47% of people deemed “overweight” by the chart are perfectly healthy.
“So to be using BMI as a health proxy – particularly for everyone within that category – is simply incorrect.”
This also means many people who are considered by the chart to be of healthy weight aren’t healthy when you look at underlying clinical indicators.
“The public is used to hearing ‘obesity,’ and they mistakenly see it as a death sentence,” says Tomiyama. “But obesity is just a number based on BMI, and we think BMI is just a really crude and terrible indicator of someone’s health,” says Tomiyama.
The findings published in the International Journal of Obesity could have major ramifications for patients, doctors, companies, and insurers. The U.S. Equal Opportunity Commission recently proposed rules that would make it legal for employers to penalize employees for up to 30% of their health insurance costs if they don’t meet 24 health criteria, including meeting a specific BMI. If the chart continues to be used, millions of people could be unnecessarily penalized.
The UCLA researchers sought to determine whether BMI correlated with actual markers of health by analyzing data from more than 40,000 people who participated in the 2005-2012 National Health and Nutrition Examination Survey. The team considered respondents’ blood pressure, triglycerides, cholesterol, glucose, insulin resistance and C-reactive protein data — markers that are linked to heart disease and inflammation, among other issues.
The team discovered that nearly half of overweight respondents and 29% of obese ones were healthy, from a metabolic standpoint. About 30% of individuals of “normal” weight were found to be unhealthy.
In other words, by BMI standards, 7.9 million adults in the U.S. have been incorrectly assessed, including 34.4 million people who are considered overweight, and 19.8 million people who are considered obese.
Tomiyama told the Los Angeles Times:
“The reason I think people rely on BMI is because it’s easy; if you know someone’s weight and you know someone’s height, then out pops this magical number. But getting blood pressure is pretty easy too. It takes maybe 20 seconds if you have the machine. And so I really think focusing on better health markers like blood pressure is a better way to go about it — particularly when we’re talking about financial penalties.
“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.”
Julie Fidler is a freelance writer, legal blogger, and the author of Adventures in Holy Matrimony: For Better or the Absolute Worst. She lives in Pennsylvania with her husband and two ridiculously spoiled cats. She occasionally pontificates on her blog.