Weight Ain't Nothin' But a Number

References to questionable R&B artists aside, weight truly is just that – a number. 

For a handful of decades, weight has been the marker we’ve used to determine how healthy an individual is. BMI, the measurement traditionally used to classify people as overweight, relies almost exclusively on a weight/height proportionality formula. If you weighed more than you should based on your height, you were classified as overweight, and therefore unhealthy.

The tide is slowly turning when it comes to this way of thinking. Recent research is even concretely demonstrating that you can’t determine someone’s health simply by his or her weight. A study published in The International Journey of Obesity states BMI isn’t an accurate barometer of heart health: the research team found that 30% of people in the normal BMI range were at above-average risk of heart disease. At the same time, 48% of "overweight" and 29% of "obese" people were happily heart-healthy. This has startling implications for the overweight population. "Using BMI categories as the main indicator of health, an estimated 74,936,678 US adults are misclassified as cardiometabolically unhealthy or cardiometabolically healthy," the team concluded in the study. 

A second study conducted by a research team at Georgia Tech and published in the journal Obesity undermines the relationship between so-called “healthy” BMIs and longevity. In this study, researchers looked at data on about 400,000 people in the U.S. who were ages 50 to 71 at the start of the study, in 1995. The researchers followed up with them through 2009, and about 112,000 people in the study had died by then. The findings showed that the “best” BMI for the people in the study in terms of their lifespan was 26, on average – a BMI that typically indicates someone as “overweight.”

The thing that’s particularly startling about BMI – and is something I was completely ignorant about until delving into this issue – is that it originated as a means to measure population trends in the 19th century. While it has the ability to compare relative weights across populations, it wasn’t originally intended to measure individuals’ health. The idea that we’re actively misusing an antiquated tool to make judgements about individuals’ health is very troubling. 

Dr. Howard Karloff, one of the authors of the Georgia Tech study, is calling for a new, modern model of assessing health, and acknowledges that a one-size-fits-all approach isn’t going to land people in the best place. He claims that we have the ability now to create “personalized BMIs” – optimal weight ranges that are different for different people and are formed based on a variety of different factors. 

All of this new information can help us to start to reframe our definitions of what true health actually looks like. Instead of obsessively comparing our bodies to a supposedly optimal standard of health, we can start to create personalized definitions of health. Definitions that are ultimately more sustainable, because they’re based on our own individual needs – and no one else’s. 

EDIT: This amazing post about a young girl who schooled her teacher on BMI was sent to me by a 99% Fit reader. Check it out!