Ways to measure your health that aren’t BMI

What is the body mass index (BMI), why is it unhelpful, and how can you measure your health instead? Read more to find out.

The Flourish team
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What is BMI?

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 wasn't 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.

How do you calculate BMI?

Calculating BMI isn't 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.

Why is BMI wrong?

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 meant 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're worth so much more than that.

Better ways to measure your health that aren't BMI:

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:

  • Eating a lot and a variety of nutrient-dense foods
  • Drink lots of water
  • Get plenty of sleep to reduce stress and allow you to focus on self-care
  • Finding a community of people who align with your values and support your goals
Headshot of Claire Siegel
Claire Siegel
Co-founder, CEO
Claire Siegel is the founder and CEO of Flourish. Claire has made it her life’s mission to help women create a sustainable approach to their physical and mental well-being.
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