Who knows what BMI is? Show of hands?
Body Mass Index (BMI) is the number doctors and other health professionals use to classify people into health categories. BMI is also a height/weight ratio, which means it doesn’t mean jack in terms of health.
To figure out your BMI, you divide your weight in kg by the square of your height in meters. Or you can just click here and let a website do it for you.
The number you get lumps you into a classification:
* Underweight = <18.5
* Normal weight = 18.5-24.9
* Overweight = 25-29.9
* Obesity = BMI of 30 or greater
Here’s the problem with BMI: say you have a male bodybuilder that is 5′6 and weighs 200 pounds. He works out every day, has no health issues, crazy muscle mass and almost not body fat. Then you have another man- a sedentary couch potato who is also 5′6″ and 200 pounds, but has almost no muscle, excess body fat and type II diabetes. Since both of these men are the same height and weight, they would be lumped into the exact same health category, based on their BMI.
Something’s wrong here.
So when people try to tell me that being overweight is unhealthy, the first thing I say is “what is your definition of overweight?” and the second thing I say is “according to who?” If they use a BMI overweight classification to back it up, that doesn’t take the quality of your body mass into account, I’m not convinced. The majority of experts aren’t convinced either.
A growing number of professionals believe that a person’s genes and lifestyle dictate their health- not their dress size.
As with anything, extremes are never good. Someone with a BMI of 35 is going to be obese and unhealthy about 99% of the time. On the flip side, someone with a BMI of 10 is dangerously underweight, and is also 99% likely to be unhealthy.
The inbetween is where it gets cloudy, and where these calssifications are false. Someone who is 20 pounds overweight (by doctor’s standards) is going to have a higher BMI than someone who is at the ideal weight for their height, but does that mean they are more healthy than the first person? Maybe. What if the ‘overweight’ person competes in triathlons and eats a clean diet, while the ‘healthy’ weighted person has never broken a sweat in their life and gets their 3 squares from a drive thru?
In Good Health,
Kelly Turner is a Seattle area ACE Certified Personal Trainer, health and fitness writer and editor of the fitness website, PhysiqueSpeak.com. To contact Kelly with any questions, you can email her at firstname.lastname@example.org.