Body Fat Percentage vs. Body Mass Index: Which One Should I Use?

Body Fat Percentage vs. Body Mass Index: Which One Should I Use?

If numbers are your measure of progress, you’ve probably measured body mass index (BMI) or body fat percentage before. The two are often used interchangeably when in fact – body fat percentage should be the go-to choice.


The differences lie in who should use it, what to use it for, and how to find it.



The formula to uncover your BMI is 703 x (weight in pounds) / (height in inches) x (height in inches). If you’ve ever measured your BMI, there’s a good chance that you’ve been shocked, or even disappointed – especially if you’re muscular. This is because those who are clearly lean and fit like football and basketball players may be deemed overweight and obese. Renowned Stanford mathematician, Keith Devlin of NPR pointed out how BMI is “physiologically incorrect”:


“It makes no allowance for the relative proportions of bone, muscle, and fat in the body. But bone is denser than muscle and twice as dense as fat, so a person with strong bones, good muscle tone and low fat will have a high BMI,” Devlin said in his opinion piece. “Thus, athletes and fit, health-conscious movie stars who work out a lot tend to find themselves classified as overweight or even obese.”


Not only is BMI inaccurate, it’s inaccurate and old. The formula is obsolete, dating back to the 1800s. It leaves out several key factors like muscle tissue, waist size, and gender – and solely accounts for height.


Body fat percentage

thrive body fat test

A much more useful tool than the scale, body fat percentage can tell you the whole story. With more context and fewer limitations, body fat percentage is much more beneficial for your health and confidence.


You can discover and keep track of this incredible tool with Thrive Fitness Atlanta’s Fit3D Body Fat Scanner. In only 40 seconds with our revolutionary technology, you can discover not only your body fat percentage but also your obesity risk, segmental muscle/fat ratio, basal metabolic rate, and much more.


Here are four reasons to consider tracking your body fat percentage and ditch the BMI:


Get the whole story.

Body fat percentage isn’t just a number like BMI – it offers an explanation with it. Unlike BMI, it can identify if you’re part of the “skinny fat” phenomenon – which is when thin people have high body fat percentages. BMI would consider someone who’s “skinny fat” to be of ideal health – when in reality, they’re subject to many health complications.


Stay on top of your goals.

If you’re looking for that summer six-pack – body fat percentage can be your best friend. All the crunches, planks, and Russian twists in the world won’t get you to your goal if you’re not focused on lowering your body fat percentage by incorporating more full-body workouts. By focusing on body fat percentage, you lose your tunnel vision and can expand your workouts.


Weight loss doesn’t equal fat loss.

If one of your S.M.A.R.T. goals is to lose weight, then body fat percentage is probably your best course to keeping track of your progress. Our Fit3D Body Fat Scanner stores your data so you can see how your entire body composition has changed, side-by-side. The scale can be misleading because a dip in the scale can translate to loss of water weight or muscle mass, not always fat loss.


Lower your risk of disease.

Body fat percentage stretches beyond just weight loss – it can lessen your chances of reaching the point of cardiovascular disease. The Mayo Clinic found that working toward a healthy body fat percentage can boost good cholesterol and remove bad cholesterol (LDL). Lower cholesterol levels mean less plaque buildup on the heart’s artery walls.
Avoid the restrictions and manipulations of BMI by contacting Thrive Fitness today. Schedule your Fit3D scan by emailing us today at

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