I’ve always considered BMI (Body Mass Index) an inaccurate measurement for assessing a person’s weight. I remember seeing a news report back in the 1990s that illustrated the flaw in this measurement by using Michael Jordan as an example. At the peak of his career, Jordan weighed about 216 lbs, and his height is widely known to be 6’6″. Here’s his BMI.
BMI = Weight in kg / Height in meters squared
BMI = 98 / 1.98 squared ≈ 98 / 3.9204 ≈ 25
That would place Michael Jordan, the picture of physical fitness in the 1990s, at the lower end of the overweight category. This brings me to an article in the Wall Street Journal discussing the origin of BMI, how inaccurate it is for assessing individual health, and what might be a better alternative for determining how healthy your weight is.
The major flaw in BMI is that it doesn’t distinguish between subcutaneous fat and visceral fat. BMI also fails to account for differences in muscle, gender, race, and age. While it originated in the 1800s and is useful for population-level data, it doesn’t fully reflect an individual’s health.
Visceral fat, which tends to be concentrated deep in the abdominal region around important internal organs and leads to weight gain around our belly, is the more concerning kind of fat. It influences our risk for developing problems like elevated blood sugar and blood pressure, which increase our odds of heart disease and Type 2 diabetes. Subcutaneous fat, which is the fat you can pinch just under the skin, is less detrimental to your health.
Wall Street Journal (free link)
Alternative methods to measure weight health include waist circumference, which provides a better sense of visceral fat, and a waist-to-height ratio. These methods may more accurately predict metabolic health, though measuring them can be challenging. Other tools, such as MRIs or DEXA scans, offer precise fat measurements but are impractical for widespread use due to cost and radiation exposure.
BMI’s effectiveness also varies by race and gender. For instance, Asians have more visceral fat, meaning their health risks increase at lower BMIs compared to other races. Women generally have more body fat than men, but their visceral fat increases after menopause, raising their health risks. Overall, BMI is just one number and shouldn’t be relied on to capture a person’s full health profile.
BMI’s usefulness can vary depending on your race and gender, notes Dr. Gitanjali Srivastava, a professor and co-director at the Vanderbilt Weight Loss Center in Nashville, Tenn.
For example, Asians are born with more visceral fat. As they age, they face risks for cardiometabolic diseases at a lower BMI threshold compared with people of other races, she says.
Wall Street Journal (free link)
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