Doctors Say Body Fat Percentage Offers a More Accurate Health Picture Than BMI—Here’s Why
Learn why traditional BMI readings may be misleading
For many people, no matter what doctor you’re seeing, the routine is essentially the same. You enter the room, sit down on the medical exam paper, get your blood pressure taken, then step on the scale. When you log on to whatever digital health platform your doctor’s office uses, you’ll find a log of your height, weight and body mass index (BMI) score. But how effective is BMI in gauging your health? New research suggests that your body fat percentage may be a better bet—here’s why.
What BMI readings reveal—and why they’re falling out of favor
BMI measures a person’s body weight relative to their height, according to the CDC. And some elevated BMI numbers reflect an association with health issues. For adults, a BMI between 18.5 and less than 25 is considered healthy. Readings from 25 to less than 30 mean a person is considered overweight, while a BMI of 30 or higher indicates obesity.
BMIs that land in the obesity category mean that a person is carrying excess weight for their height, the CDC reports. That may increase the risk of high blood pressure (hypertension), high cholesterol and other chronic health conditions.
Woman's World Answers
While some people view their BMI score as the ultimate metric of health, others, including doctors, have recently taken to social media to call out issues with using BMI scores as a predictor of health. A more accurate measurement poised to take its place? Body fat percentage.
BMI vs body fat percentage: What the research shows
A new study published in Annals of Family Medicine in June followed more than 4,000 adults aged 20 to 49 for 15 years to assess whether body mass index (BMI) or body fat percentage (BF%) better predicted mortality risk. Researchers found that body fat percentage was a significantly stronger predictor of heart disease mortality and overall risk of death compared to BMI.
“BMI can lull people into a false sense of security.” —Hector Perez, MD
Why is that? “Body fat percentage tells us how much of a person’s weight is actually fat, which is far more relevant to long-term health risk than weight alone,” explains Will Haas, MD, MBA, Founder & CEO of VYVE Wellness. “Unlike BMI, it reflects the quality of weight, not just the quantity.”
Hector Perez, MD, Lead Bariatric Surgeon at Renew Bariatrics, says that he’s seen the difference in the two health metrics directly in his work.
“BMI is a blunt tool, simply being a height-weight ratio that ignores the actual content of that weight,” says Dr. Perez. “As a bariatric surgeon, I’ve treated countless patients with a normal BMI who still have dangerously-high visceral fat.”
The limitations of BMI readings
“BMI doesn’t distinguish between fat and muscle, which means someone lean and muscular can score as ‘overweight’ while someone with high body fat and low muscle may appear ‘normal,’” says Dr. Haas. “This study reinforces that relying solely on BMI can obscure true metabolic risk.”
As Dr. Perez adds, “this study directly challenges the assumption that BMI is a valid proxy for health risk. It shows that BMI can miss ‘normal weight obesity’ and overestimate risk in athletic individuals.”
Although some people may have a normal BMI score and look healthy, our experts say that doesn’t necessarily mean they’re healthy on the inside.
“We call it TOFI: thin outside, fat inside,” says Dr. Perez. “A young woman might be a size 6 with a BMI of 22, but have 35 percent body fat and visceral adiposity surrounding her liver and pancreas. I’ve seen such patients present with PCOS, fatty liver or prediabetes despite looking fit. BMI can lull people into a false sense of security.”
That’s especially important for women over 50 to keep in mind. “Older adults experience sarcopenic obesity, where they lose muscle but maintain or gain fat,” says Dr. Perez. “Body fat percentage and waist circumference become even more relevant as muscle loss masks metabolic risk. I’d wager that if the study followed older cohorts, the findings would be even more stark.”
Should you get your body fat percentage checked?
It goes without saying that not everyone with a normal BMI will also have a sneakily unhealthy body fat percentage, but experts say it could be worth checking if you have any symptoms.
“Don’t be fooled by the number on the scale,” says Dr. Haas. “If you’re tired, inflamed or noticing metabolic issues, it’s worth asking your doctor to check body fat percentage and waist circumference to get a clearer picture of what’s going on.”
While BMI is still widely used as a metric for health, Dr. Haas says the shift in moving away from BMI alone is already happening.
“As access to better tools improves, we’ll likely see a shift toward metrics that actually reflect metabolic health—like body fat percentage, waist circumference and even muscle mass—as the new standard for risk assessment,” says Dr. Haas.
