Dental Health Topics

Do You Know Your BMI?

Do You Know Your BMI?

Your body mass index, or BMI, is a derivative of your height and weight. It’s a number that can be helpful if you know the history and how to interpret it.

Let’s dig in!

Calculating BMI
To calculate your BMI, first convert your weight from pounds to kilograms. Then divide that by your height (in meters), squared.

Alternatively, you could divide your weight in pounds by your height in inches (squared), then multiply by 703.

Or, you can use an 
online calculator!

The resulting number slots you into one of four categories: underweight (under 18.5 kg/m squared
), normal weight (18.5 to 25), overweight (25 to 30), or obese (over 30).
Ok, so if you’ve done the math, you now know your BMI.

But what exactly does that tell you? Are you in an underweight or obese category but don’t think you should be? You’re not alone.

The BMI is helpful for population studies, but not necessarily individual health. Let’s explain.

A History

The BMI formula was developed in the 19th century by mathematician and astronomer Adolphe Quetelet, whose work centered on creating a picture of the ideal or average person. He came up with the BMI for his own purposes – so the figure wasn’t even created to be a reflection of individual health.

Starting in the 20th
 century, insurance companies began noticing that their heaviest clients had the highest death rates, so finding a way to determine their insurability became important. And thus, they started the cascade of everyone from epidemiologists to your family doctor, to now you, calculating your BMI.

What Doesn’t BMI Tell You? 

It doesn’t tell you how healthy you are at any given moment.

It doesn’t tell you how much muscle mass you have.

It doesn’t tell you how much fat mass you have, or where that 
fat is distributed on your body.

Quite simply, all BMI tells you is where your height and weight fall on a spectrum.

That means an Olympic athlete can be classified as obese, but a couch potato as normal or healthy. This despite the athlete being in much better shape. 

BMI Can Still Be Useful

So, let’s say you calculate your BMI today, and then in 10 years, it’s higher. Assuming you haven’t grown in height, that tells us you’ve gained some weight, which many people do as they age.

But weight gain in adulthood (if the gain is in fat tissue alone), can indicate a 
higher risk for chronic diseases. So, this increase in BMI might be telling you to prioritize your health a little more. Or, it can tell you you’re now in a healthy weight range where you might have once been underweight. Or, conversely, that your healthy baby steps are paying off!

Bottom Line 

Tracking your BMI can be an important step in calling a spade a spade. That is – if you know you need to work out more, then work out more. If you know you should cut down on the nightly cocktails or daily dessert, then do that.

But don’t let it trip you up if you’re already living a healthy lifestyle. And if you need help stopping 
overeating, know that you’re not at all alone, and there are resources to help.