Kim Yawitz, RD
I can’t even begin to tell you how many of my prospective client calls start the same way: “I went to the doctor, and he said I had a 25.6 BMI. So I called you because I need to lose weight.”
And sometimes, that’s fairly accurate. Or, at least, these prospective clients have an opportunity to improve their health by losing a few pounds.
I have a TON of respect for physicians. But I gotta tell you–I often call BS on the notion that someone with a slightly elevated BMI must lose weight.
In this post, I’m going to explain what BMI is, how it’s interpreted in clinical settings, and why it’s not always the best measure of health in active populations.
What is BMI?
Body mass index (BMI, for short) is a quick screening tool that clinicians use along with other diagnostic tools to assess disease risk.
And when I say quick, I mean QUICK. Here’s how to calculate your own BMI in about 15 seconds:
BMI=(Weight (lbs)/height(in)/height(in)) * 703
So now that you have your score, let’s talk about how it would be interpreted in a clinical setting:
- <18.5 = underweight
- 18.5-24.9 = normal weight
- 25.0-29.9 = overweight
- 30.0+ = obese
So let’s say you have a 25.6 BMI (a number that I picked somewhat arbitrarily, FYI). By CDC standards, you’d be considered to have overweight. No, that’s not a typo. The preferred terminology is to “have overweight” or “have obesity,” rather than “be overweight” or “be obese.”
25.6 BMI: What’s It Mean for Your Health?
If you fall into the overweight or obese category, you might be wondering what this means for your health. And the answer is…it depends.
Lots of studies have linked higher than normal BMI with negative health outcomes, including heart disease, cancer, diabetes, stroke, and–more recently–increased risk of complications from COVID-19.
With that in mind, of course, your doctor would want to err on the side of caution if your BMI is a bit high (which would be the case if you have a 25.6 BMI). That’s why you go to the doctor, right? To keep you healthy?
That said, as a registered dietitian who works with a lot of strength athletes, I see a lot of prospective clients and clients who are just tiptoeing into overweight territory. And I generally don’t worry as much about a slightly higher than normal BMI in athletes.
BMI in Athletes
Think back to the BMI equation a few paragraphs up. Do you notice anything…fishy?
Well, I’ll tell you. BMI factors in two metrics and two alone: height and weight.
The problem with this is that strength athletes generally have more muscle and higher bone density than people who don’t work out. And, while muscle weighs exactly the same as fat (don’t let anyone try to convince you otherwise), it’s also denser.
What’s more, more muscle and more bone are GOOD things. Because people with more muscle generally have faster metabolism, being muscular can actually protect you against diseases typically associated with obesity. Yep, even if your BMI is a little high.
In fact, the stronger you are, the more likely you are to have a higher BMI.
Wait, So Now What?
Are you confused yet? I don’t blame you!
First of all, let me get a couple of key points out of the way.
One: I am in no way disrespecting the medical profession. If your BMI is a little high, it’s probably safest to assume that your risk might be a bit elevated and take stock in opportunities to improve your health until you have more data. This might mean getting some labs checked, implementing healthy sleep and stress reduction rituals, and working with a registered dietitian (like me!).
And two: When I say strength athletes, I mean STRENGTH athletes. Please do not dismiss any health concerns related to your BMI ever, but especially if you’re not consistently working your muscles hard. One set of bicep curls during your weekly Bachelor viewing does not a strength athlete make.
Now that that’s out the way, here’s what I’d suggest.
Again, gather more data. Don’t pass on other assessments your doctor recommends, including lab work, imaging studies, and sleep studies.
Second, grab a tape measure and check the following:
- Your waist circumference. Having a waist circumference grerater than 40 inches if you’re a guy and 35 inches if you’re a lady increases your risk of obesity-related complications.
- Your waist:hip ratio. To do this, you’ll divide your waist measurement by your hip measurement. You’d be considered higher risk if your ratio is greater than 0.85 if you’re a lady, or 0.9 if you’re a guy.
Alternatively, you can look at body fat percentage. We use InBody at 26 and offer free quarterly scans to our unlimited and 9x/month members. Non-members can come in and have a scan (which I help you interpret) for $20.
Interested in scheduling? Email firstname.lastname@example.org for more info!