There’s been a lot of buzz about BMI recently, due to the underlying conditions exceptions for Covid-19 vaccines. BMI stands for body mass index, which is a measurement that scientists use to determine how heavy you are relative to your height.
The controversy is over the accuracy of this measurement. Namely, are scientists able to determine whether or not someone is obese, and therefore qualified to get the vaccine, using this measurement?
First, let’s go over how to calculate BMI. You can use this link to calculate, or use this formula:
703 * (weight in lbs) / (height in inches)^2 = BMI
So, if someone is 5’5 and 150 pounds, they have a BMI of 25. Here are the categories:
- BMI below 18.5 = underweight
- BMI 18.5-24.9 = normal
- BMI 25-29.9 = overweight
- BMI 30 and above = obese
So, a BMI of 25 is technically “overweight.” There’s been an outcry over the inaccuracy of using this system, and for good reason. It doesn’t take into account what you’re made of. If you have tons of muscle and very little body fat, you could be considered overweight or obese. The measurement simply looks at how much you weigh on the scale.
This is also the beauty of BMI. It’s not intended to be accurate on a person-by-person basis. It’s made to measure changes in size of large populations. Think about it this way: you can calculate the BMI of every person in a country who either has a drivers license or passport, simply because height and weight are disclosed.
So, is BMI inaccurate? Yes, if it’s misused. If it’s used to measure changes in a large group of people, it’s surprisingly accurate. That’s why the government felt confident using it for vaccine purposes.