Ilona Maher's TikTok Reminds Us That BMI Isn't the Best Indicator of Health

Over the course of the Paris Olympics, we've seen athletes of all shapes and sizes competing at the top of their game. Although no two athletes look exactly alike, internet trolls have inevitably conflated thinness with fitness, defending these tired standards using antiquated indicators of health. At-home commentators take it upon themselves to criticize Olympic athletes — particularly women — on the basis of the Body Mass Index (BMI). But given what we now know about health and weight, is BMI still a relevant measure of health and fitness? And if so, why do some Olympic athletes have a higher BMI?

In a July 10 TikTok with over one million likes, Team USA rugby player Ilona Maher decided to address this topic head-on, responding to a comment speculating about her BMI. "I think you were trying to roast me, but this is actually a fact. I do have a BMI of 30. Well, 29.3 to be more exact," she said, adding that she's technically been considered overweight her entire life.

Maher went on to say that, after consulting with a dietitian, she learned that BMI isn't always helpful for athletes, since it doesn't account for lean muscle mass or physical activity. "BMI doesn't really tell you what I can do. It doesn't tell you what I do on the field, [or] how fit I am. It's just a couple numbers put together," Maher said. "So yeah. I do have a BMI of 30. I am considered overweight. But alas — I'm going to the Olympics, and you're not."

To get a better sense of how BMI relates to athletes, we spoke to experts about what it is, where it comes from, and what it's used for. Read on to see if BMI still matters (especially for athletes), or if it's time to retire the test for good.

Joanna Gregg, MS, RD, is a dietitian at MyFitnessPal.
Natasha Bhuyan, MD, is the vice president of in-office care at One Medical.

"BMI is used to estimate body fat based on a person's ratio of height to weight," says Joanna Gregg, MS, RD. The exact equation is weight (lbs) divided by height (in²) multiplied by 703. However, BMI has a problematic history that affects its overall accuracy. "BMI [is] based on a sample from the Netherlands, and it was actually based on higher-income white men," says Natasha Bhuyan, MD. "So that's not really reflective of the general population."

Issues with the BMI persist when it comes to athletes, and that's largely because the test oversimplifies health and fitness. "Many Olympic athletes might be labeled as being overweight or obese even though they lead a healthy lifestyle, they're clearly staying active and exercising, many will eat a diet [with] whole foods, and really it's because they have a high muscle mass," Dr. Bhuyan explains. Gregg adds that BMI uses weight compared to height as an indicator of fat mass, but makes no distinction between fat mass and muscle mass. This means that the BMI generally overestimates body fat in populations with higher muscle mass (athletes included). "Athletes tend to have a higher muscle mass than the general population which can put their BMI in the overweight or obese category," Gregg explains.

According to Gregg, BMI has previously been used to identify health risks and possible chronic conditions (higher BMIs have been associated with higher rates of heart disease, diabetes, and certain types of cancer, per the National Heart, Blood, and Lung Institute). Still, Dr. Bhuyan explains that BMI doesn't have any direct correlation to health outcomes, and there are plenty of ways to measure health more accurately. In fact, studies have shown that BMI can make inaccurate assumptions about health when compared to more objective measures like cholesterol and blood sugar levels.

"The bottom line is that you can have a low BMI and still have risk factors about your health that need to be addressed, or you can have an elevated BMI and be perfectly healthy," Dr. Bhuyan says. "Health and wellness mean different things to different people, but we want to know who you are, [and] what your lifestyle factors are. Are you drinking alcohol? Are you smoking? What's your family history? What do your other labs look like? I think that overall picture is a much more accurate reflection of someone's health."

No matter what TikTok commenters say, health is so much more than a simple equation. "We don't want people to feel shamed or labeled in healthcare, and that's what BMI does," Dr. Bhuyan says. "It inaccurately labels people and it actually leads to people engaging less with their health." For all those watching the Olympics, it's important to recognize that health and fitness looks like a million different things, and not just one specific body type (as Maher so beautifully explained). "Maintaining an active lifestyle and healthy eating patterns are always a good indicator of health," Gregg says. "All body types are different and should be loved and appreciated for all the things they accomplish."

Chandler Plante is an assistant editor for PS Health & Fitness. Previously, she worked as an editorial assistant for People magazine and contributed to Ladygunn, Millie, and Bustle Digital Group. In her free time, she overshares on the internet, creating content about chronic illness, beauty, and disability.