The Sliding Scale: What you need to know about BMI calculations


Personally I don’t remember ever seeing a BMI chart in my doctors office until I was in high school.  Back then though I was playing basketball in school and soccer in the off season so it didn’t really make sense for me to pay attention to anything that had to do with my weight.  I knew I slimmed down during a sport and got a little more weight on in the off season.  It’s amazing how simple it all was back then!

Strangely, as I started to research, the BMI scale has been around since a guy named Adolphe Quetelet developed what he called “social physics”. However it didn’t gain momentum in popularity until a paper by Ancel Keys was published about it in the July 1972 edition of the Journal of Chronic Diseases.   Keys was an American scientist who studied the influence of diet on health.

What is BMI?

BMI or Body Mass Index is a chart used by doctors to determine if you are underweight, normal, overweight or obese using measurements of your height and weight.

The BMI is an attempt to quantify the amount of tissue mass (muscle, fat, and bone) in an individual, and then categorize that person as underweight, normal weight, overweight, or obese based on that value. – Wikipedia

The idea of the scale is that there is a target weight range that you should be in, not a specific weight you should be at.

Pros if BMI

BMI shows a simple measure of a person’s thickness or thinness. This straight forward gauge allows health professionals to discuss weight problems more objectively with their patients.

The “normal” weight for a person is a range which is helpful because no person weighs the exact same weight every day of their lives.  If you gain a few lbs or lose a few lbs, but stay within your ideal weight range, it’s ok.

Cons of BMI

BMI was explicitly cited by Keys as appropriate for population studies and inappropriate for individual evaluation. — Wikipedia

If Keys opinion is right, it seems that the BMI  number is not specific enough to be good for an individual to make use of.

My thoughts on BMI

My medically suggested ideal weight  is about 30 lbs lighter than I am now.  I think, having been that skinny in the past, that I look and feel a bit anorexic at that weight.  I know that when I was my ideal weight I was playing high school and college basketball 20 hours a week.  The second time I was that weight I was living out of state and became so depressed that I stopped eating and technically probably really was anorexic. (Luckily moving home cleared up the depression and I put the weight back on.)

Normal people, even fitness conscious people, can’t keep up a schedule of 20 hours a week unless they are super dedicated.  I like to think of myself as fairly dedicated, but not sure I could do that many hours of activity continuously into my later years.  I feel like maybe 20 lbs lighter is about my ideal and according to BMI I’d still be in the “normal” range if I got to that weight.

As I’ve gone through my fitness journey over the last two years my BMI has dropped from 31.9 to 26.6.  Sadly that number still makes me overweight but I’m down from obese!!!  I hate that word by the way, especially for my body type.  I knew that I was overweight, but the picture I have in my head of an obese person is someone very much larger than I have ever been.

I guess that’s why the BMI is there because by just looking at someone you can’t tell where they are on the scale.


For an online BMI calculator click ==> HERE !