The Body Mass Index (BMI) is BS

BMI ComparisonThe body mass index (BMI), or Quetelet index, was developed between 1830 and 1850 by the Belgian polymath Adolphe Quetelet. The BMI formula is a measure of relative weight based on an individual’s mass and height.

It doesn’t take a rocket scientist to know that muscle weighs more than fat, so plenty of bodybuilders and athletes could easily be classified as “obese” according to this method. This is why trainers are more likely to measure your body fat percentage and throw the BMI out the window. According to my personal BMI, based on my height, I should weigh 135 pounds. I can assure you, I would look anorexic at that weight. I haven’t weighed that since my freshmen year of High School.

In early 2000, the American Journal of Clinical Nutrition published a study showing that body-fat percentage may be a better measure of your risk of weight-related diseases than BMI.


The BMI Formula Breakdown:

  • Very Severely Underweight: Below 15
  • Severely Underweight: 15 to 15.9
  • Underweight: 16 to 18.4
  • Normal (healthy weight): Between 18.5 and 24.9
  • Overweight: Between 25 and 29.9
  • Obese Class I (Moderately obese): 30 to 34.9
  • Obese Class II (Severely obese): 35 to 39.9
  • Obese Class III (Very severely obese): 40 and higher

Here are 2 reasons why I call BS to the BMI:

body fat percentage measurement1. The guy who dreamed up the BMI explicitly said that it could not and should not be used to indicate the level of fatness in an invidual.

When Mr. Quetelet introduced the BMI in the early 19th century, the fact is, he was a mathematician, not a physician. He produced the formula as a quick and easy way to measure the degree of obesity of the general population to assist the government in allocating resources. In other words, it is a 200-year-old-hack.

2. It is scientifically nonsensical and physiologically wrong.

It ignores waist size, which is a clear indicator of obesity level. It makes no allowance for the relative proportions of bone, muscle and fat in the body. Bone is denser than muscle and twice as dense as fat, so a person with strong bones, good muscle tone and low fat will have a high BMI. Again, why athletes and fit individuals tend to be classified as overweight and obese. The BMI cannot differentiate between The Terminator and The Pillsbury Dough Boy.

My Simple Conclusion: Stick with measuring your body fat percentage and toss the BMI in the dumpster.

Tristan "Lucky"

Written by: Tristan “Lucky”