It's time to throw this broken calculator in the garbage.
The BMI (body mass index) is BMI is a formula that allegedly measures your body fat. It is calculated by dividing your weight (in pounds) by your height (in inches). Already, that's a false dichotomy. Muscle is much denser than fat (by about 18%), so the same amount of muscle will actually weigh more. By design, that's something the BMI can't account for. But wait! There's more.
The BMI can't calculate how healthy you are.
It can't tell whether or not you smoke (which is almost guaranteed to make your life shorter), or how often you exercise (which is almost guaranteed to extend your life expectancy). The only thing the BMI can measure is your relationship with gravity relative to how far away your head is from the ground. It's a completely arbitrary number, and it's been used to support the myth that a heavier weight is automatically unhealthy.
Fat ≠ Unhealthy
Healthy lifestyle habits (such as regular exercise and a diet with lots of fruits and vegetables) are associated with a decrease in mortality for everyone- regardless of their BMI. Studies are finding that overweight and obese (aka fat) people were found to be at no greater risk of developing or dying from heart disease or cancer, compared with normal weight people, as long as they were metabolically fit (via). Weight isn't actually an indicator of health (for some illnesses, being what's considered overweight could actually prolong your life, like for patients with heart disease or other metabolic disorders). So the BMI is not just useless, it's actually harmful, when it comes to medical data. Which makes sense when you remember that the BMI was created by someone with ZERO medical background.
Yup. The BMI was created by Adolphe Quetelet. He was a mathematician, astrologer, and sociologist. He was not a doctor- he never studied medicine at all. And the BMI was created to study white people specifically. People whose bones tend to be less dense, which puts them on the lower end of the BMI scale. Why do we use the BMI scale again???
Yup. The BMI is making people a lot of money. Insurance companies use the BMI to set premiums, which means that people with higher BMIs end up paying a lot more (some studies suggest it's 22% more). In 1998, 29 million Americans became fat overnight when the guidelines used to define 'fat' changed on the BMI scale from 27.8 to 25. And the diet industry has been making millions off the 'epidemic'. It doesn't matter that body weight is not a permanently controllable factor. Who cares about bad science when you can get rich off fat peoples' existence?
Dear BMI: You've been dumped.
I'm going to focus on the things that are ACTUALLY going to make me healthy: Getting more exercise, no more cigarettes or heavy drinking, eating more fruits and vegetables- and not treating my body like crap just because some arbitrary number and bad science says I should. Because I DO love my body.