Should I Care About My BMI?
Sort of. You should take an interest in your health, and BMI can give you a mini gut check on “at-risk status.” It’s probably fairly rare that someone learns something new from their BMI, though — if your BMI is high enough to be important to your health, you probably know.
What BMI Is Good For
BMI is good for statistical work on information about large groups. This is what it was designed for — a cheap, easy proxy suitable for aerial views of populations.
BMI is good as a cheap, numerical screener in places where lots of individuals are seen regularly. We are seeing this more and more. You visit the doctor, and your BMI appears in your chart. This isn’t necessarily bad, although what happens next can be.
What BMI Is Bad For
BMI is bad for making definitive statements about health or body fat. BMI just can’t do that. It’s a cheap estimate — just as stepping on a weight scale is just one (small) part of the health (and even weight!) story. Like weight, BMI is just a guesstimate about likely body fat, not a measure of it.
BMI is bad for tracking individual progress. There is no ideal BMI — the healthy range is wide. If your BMI is extremely high (like 40), it may be a helpful item to monitor, but your main focus should almost always be on different questions. Like whether you are getting regular exercise and good nutrition, and still keeping total calories in a good place.
What Should I Track?
Maybe your weight, and maybe even your BMI, but maybe not. This is where goals come in. If your doctor has called attention to your BMI and recommended you lose weight, ask about health issues you can track together (like cholesterol or blood sugar stability). A small weight (fat) loss can move those in the right direction, and that focus means you can work on something that helps you personally, instead of serving a more abstract idea that weighing less is usually better.
At any point, you should think about goals that don’t involve the scale at all — like having more energy, keeping up with your kids, or getting better at an activity you enjoy.
Do you have a favorite nonscale victory?