Rugby Olympic medalist Ilona Maher is taking on BMI and winning

US women’s rugby center Ilona Maher helped Team USA win a bronze medal Tuesday in the rugby sevens competition against Australia in the 2024 Paris Games. (Christophe Petit Tesson/EPA-EFE/Shutterstock via CNN Newsource)

With her trademark red lipstick and a killer right arm that easily sweeps her opponents out of her way, US women's rugby center Ilona Maher ran Team USA toward its first bronze this week at the 2024 Paris Olympic Games.

But her reaction to hecklers who call her masculine and criticize her weight as "obese" is winning additional accolades from fans and critics alike.

"I used to get those comments all the time, people being mean or calling me manly or whatnot," she told CNN. "But now I have 2 million friends who will come after you and take you down if you try and say anything mean to me."

Before the Olympics began, Maher responded to one critic who commented, "I bet that person has a 30 BMI," which stands for body mass index, a controversial measurement the medical profession uses to characterize weight.

"I think you were trying to roast me, but this is actually fact — I do have a BMI of 30. Well, 29.3 (to be) more exact," she posted in mid-July on TikTok.

"I am considered overweight. But alas, I'm going to the Olympics, and you're not."

Maher has posted poignant videos about the pain that those hateful, often anonymous, comments accusing her of being overweight or on steroids can cause.

"As you can probably tell, I've been crying a little bit," she posted in December 2022.

"They think women should be fragile and petite and quiet and meek, but that's not the case," she said. "Women can be strong, and they can have broad shoulders, and they can take up space, and they can be big. I think I'm getting emotional because I feel very passionate about this. Don't let anybody try to define or dictate how you feel about yourself. You get to decide that."

The problem with BMI

As currently defined, a BMI between 18.5 and 24.9 is a healthy weight, between 25 and 29.5 is overweight, between 30 and 34.9 is obese, between 35 and 39.5 is class 2 obesity, and anything more than 40 is "severe" or class 3 obesity, which used to be called morbid obesity. People are considered underweight if their BMI is lower than 18.5.

Critics say the term BMI has become a societal judgment by lumping individuals into arbitrary categories that perpetuate misconceptions about body weight. Even with all the backlash against "fat-shaming," weight stigma against the seriously overweight or those who have obesity remains deep-rooted, according to research.

A BMI measurement can be flat wrong in some cases, Thomas Wadden, a professor of psychology at the Perelman School of Medicine at the University of Pennsylvania, told CNN in an earlier interview.

"Consider a young woman who is 5 feet 5 inches and 150 pounds. She would be on the cusp of being overweight with a BMI of 25," said Wadden, former director of Perelman's Center for Weight and Eating Disorders.

"But she may be incredibly muscular, and she may have most of her weight in her lower body, where it's not as damaging to her health as weight in the upper body," he said. "She could easily say, 'I am in perfectly good health, so just take your BMI of 25 and shove it.'"

That's exactly the scenario facing Maher. She posted about her BMI — and how little it reveals — in the mid-July TikTok.

"I'm 5 (feet) 10 (inches) and 200 pounds. And I have about — and this is an estimate — but about 170 pounds of lean mass on me," she said. "That BMI doesn't really tell you what I can do … how fit I am. It's just a couple of numbers put together, doesn't tell you how much muscle I have or anything like that."

BMI measurements can overestimate body fat in athletes and people with a muscular build or a larger body frame. Conversely, BMI can underestimate body fat in older adults and anyone who has lost muscle, according to the Harvard T.H. Chan School of Public Health in Boston.

There is a movement in the medical profession to move away from crude BMI measurements in clinical practice. In June 2023, the American Medical Association adopted a new policy suggesting other measurements, such as waist circumference, measurements of visceral fat, body composition, and genetic and metabolic factors, be used along with BMI to determine health risks.

"BMI is based primarily on data collected from previous generations of non-Hispanic white populations," the AMA wrote. And while it's "significantly correlated with the amount of fat mass in the general population," the association said, it "loses predictability when applied on the individual level."