What does your BMI say about your health? (Photo: Alan Cleaver, Flickr)

All of us feel more comfortable when we’re able to put labels on the things in our lives. Not all labels we give or receive are fair or tell the whole story, but the world is a confusing place. Our minds prefer order to chaos, so we summarize and label the world around us, even if those labels themselves are sometimes wrong.

In terms of our physical and mental health, there’s been a tug-of-war lately concerning everyone’s body mass index, or BMI. The national average has been steadily going up for decades, and being overweight has become, in a way, the "new normal." So can you have a higher BMI but still be just as healthy as a person with a lower BMI?

How do you calculate BMI?
The easiest way to calculate BMI is to go to this website and enter your height and weight. However, a more accurate reading and description are found here. It includes measurements of waist, wrist, hip and forearm circumference to help you get a better understanding of your real body fat percentage.

What is BMI, exactly?
BMI calculates your size relative to your height and weight. It is calculated differently for children and teens. From age 20 onward, though, BMI categories remain the same for both men and women. Here are the BMI categories for anyone 20 or older: A BMI under 18.5 is underweight. BMI between 18.5 and 24.9 is normal weight. BMI of 25 to 29.9 is overweight, and a BMI of 30 or more is obese.

I mentioned this in an article I did last year, but it bears repeating. BMI is, in theory, meant to roughly calculate the amount of body fat a person has. Probably 90 to 95 percent of the time, a man who’s 6 feet tall and weighs 250 pounds is obese and has a dangerously high amount of body fat. However, someone like Dwayne "The Rock" Johnson isn’t what you would consider obese, is he? Therein lies the problem.

People with a higher BMI really have more health risks.
The reason I’m bringing all of this up has to do with this recent study. The study comes out of the University of Glasgow, Scotland, and it includes nearly 120,000 participants. I like to draw attention to these bigger studies, because they're likely to give us more accurate and reliable information.

Normally, when scientists take into account BMI of people they're researching, what they find is correlation between negative health effects and a higher BMI. It makes sense to them and to us that a person who is morbidly obese has a greater chance of having a heart attack, right? This correlation makes sense. The problem has been that there hasn't been enough research into if there's a direct causation between these side effects. We've long assumed higher BMI is a risk factor for heart disease, but this study looks at that risk directly.

What did these researchers do differently? They looked at their test subjects independent of age, sex, alcohol intake or smoking history. These are most commonly the concentration of other studies, so it was important to not focus on their related health effects. What the researchers found is that a higher BMI alone shows a significantly higher risk of hypertension, heart disease, Type 2 diabetes and high blood pressure (both systolic and diastolic). Essentially, on average, a higher BMI alone does make us more likely to suffer from one or more of these side effects.

But what about being "fat and fit"?
Bodybuilders like The Rock are in a class of their own. They may not suffer from the same risks as the people in the above study, but that’s because their body fat percentage is significantly lower than even the average person's. Having more muscle weight is not necessarily a burden to our health, but again, it’s rare to find people who fit into this category.

The debate is still raging. Many think you can be fat and fit, and I don’t necessarily disagree. Some people, for a variety of reasons, simply have always and will always struggle with their weight, regardless of how well they eat or how much they exercise. So it is possible to be overweight and run a marathon or hike the Appalachian Trail. Our BMI or weight isn’t always everything.

However, keep this in mind.
Even though being overweight and fit is possible, that doesn’t mean you’re overweight and healthy. There’s a big difference between being in shape and being the picture of good health. I think that’s where we see a lot of confusion and misunderstanding. The words "fit" and "healthy" seem really similar to us. They’re often used interchangeably when discussing research or wellness topics, but they’re not really the same thing, are they?

Any of us can be one of the following: fat and unhealthy, fat and fit, normal weight and fit, normal weight and healthy. However, we can also be The Rock—theoretically (according to BMI) fat but still healthy!

Therein lies the problem. We’re all too likely to place labels on people and things that don’t quite fit. We try to make them work or explain nuance to suit our needs. For me, I don’t really like BMI calculations all that much, but I see their worth for the general public. Between you and me, the best way to know your own health risks is to do the work yourself. Take measurements, get an accurate calculation of your body fat percentage, check your blood pressure regularly, and ask your doctor as many questions as you can think of. 

Jay McKenzie loves soccer, history and feeling great. He's on a quest to eat better and exercise more, and he wants to share his experiences along the way. You can email him at [email protected] with comments or questions. The opinions expressed in this column belong solely to the author, not Nooga.com or its employees.