Why BMI Is a Terrible Indicator of Health
As one would expect, we hear a lot about weight - many trying to lose it, a few trying to gain it. And one way we look at weight in the medical field (and otherwise) is BMI. For those who may not be familiar, BMI stands for body mass index. This index considers your height and weight and then, based on an equation, spits out a number, aka your BMI. If you're curious what your own BMI is, you can easily calculate it by one of the following equations:
Then based on that number, you fall into one of five categories:
At first glance, some of you might think this makes sense. If you weigh a lot for a certain height, you would be considered overweight, obese or severely obese. And if you weigh a little for a certain height, you would be considered underweight. So, what's the problem then?
There are a few, actually. First, BMI doesn't consider how your weight is distributed or how much or how little body fat you have. It only takes into account height and weight. This is problematic for a few groups of people, especially athletes (muscle is denser than fat) and pregnant women (for obvious reasons). Additionally, since some racial and ethnic groups may have more lean tissue per pound of body weight than others, BMI may wrongly assign some into the overweight or obese categories.
But the biggest reason BMI is a problem is that it doesn't consider overall health, habits or lifestyle, nor does it do a good job of predicting disease or mortality. A lot of people might technically be in the overweight or obese categories, but are perfect pictures of health. In fact, there is plenty of research like this study that shows overweight being associated with decreased risk of mortality, while being underweight associates with an increased risk.
So, if BMI is far from accurate as an health indicator or predictor, why do we use it so much? Well, in short, it's easy, inexpensive and quick.
But, those are not good enough reasons. That leads us to ask: what can you do about it? One simple thing you can do, especially if seeing or hearing your weight is a trigger, is to ask your doctor or practitioner NOT to weigh you; so many of our doctors' visits don't require that number on a scale. In for a suspicious mole removal? A sore throat? A hurt arm? A well visit? If you're feeling well, and if there hasn't been noticeable rapid weight gain or loss, you should feel free to decline that weighing. And if there IS a medical reason to weigh you, you can simply ask for them not to share that number with you. Some of our clients who have followed this advice report back decreased stress related to doctors' visits and increased feelings of freedom. Don't let a scale, which doesn't know what it's talking about most of the time, dictate even a minute of your emotional wellbeing.
Be well, everyone!