BMI, or body mass index, is a tool developed by Belgian astronomer Adolphe Quetlet in the 1830’s, originally known as the Quetlet Index. Quetlet wanted to know if the laws of probability could be applied to humans at a large population level. Basically, he wanted to know if the same rules of probability that apply to figuring out how likely you are to roll snake eyes on a pair of dice would apply to figuring out human health outcomes. It was meant to be a statistical tool, not a basis for medical diagnosis.
Quetlet determined the proportions for l’homme moyen, or the average man. To Quetlet, this was the perfect male body upon which to base his model. Anything else was “deform[ed] or disease[d]... or [a] monstrosity.” Keep in mind...this man was not even a doctor.
About a century later, it was rebranded as the Body Mass Index, and was used to classify people into “underweight”, “normal”, and “overweight” groups, largely understood at the time to mean “needs a little work”, “looks good”, and “oh no”, based solely on their weight.
Calculating BMI is not that difficult. BMI is your weight (measured in kilograms) divided by your height (in meters) squared. It’s really that simple, and really that unable to take any other factors into account. The Rock is 6’5” and 260 pounds, and his BMI puts him in the “obese” category. Insane, right? We all know the Rock is in great shape. That’s why we say BMI is an oversimplified ratio that can’t possibly represent all aspects of your health.
There are a number of issues with BMI as we currently understand it. One of the more obvious problems is that BMI only takes body weight into account, without correcting for activity level or other health markers--think cholesterol levels and blood pressure. Some studies have revealed that people in the “overweight” category actually have the lowest mortality risk of all groups.
Quetlet also exclusively used a white European male population to create his model, which means he didn’t account for genetic or ethnic differences in outcomes. It also didn’t account for gendered differences in health outcomes.
One of the wilder issues with BMI was its reset in 1988. The NIH suddenly changed the thresholds for the “overweight” and “obese” categories, causing millions of Americans to become classified as “overweight” overnight (without, ya know, gaining any weight). Around the same time, a doctor and the chairman of the NIH BMI research panel, Xavier Pi-Sunyer, also served as a paid consultant for a drugs and weight loss company.
In fact, J. Eric Oliver, in the 2005 book Fat Politics, noted, “It is very difficult to find any major figure in the field of obesity research… who doesn’t have some type of financial tie to a pharmaceutical or weight loss company”.
Perhaps the biggest issue with the current use of BMI is that we rely way too much on it to understand our worth. Our ratio of height and weight has no bearing on our value as human beings; we are worth so much more than that.
There is so much more to your health than just the number on the scale or your BMI (which are really almost the same thing anyway). Here are a few other, better ways to measure your health:
This is one of the major ways Flourish is designed to help you improve all aspects of your health! We’re here with expert advice, coaching, education, and a community to help you reach all your healthy lifestyle goals. Sign up for our waitlist today here!