Ahhhh, the wonderful BMI scale.
This method of measurement has shown us how serious the obesity epidemic has becoming in the United States and other western-influenced countries.
For the general public, the BMI is mostly good, there are only a few exceptions where a BMI can paint a false reality to the actual health of a person.
BMI stands for Body Mass Index. It can be defined as a way of relating weight to height. You simply take your weight in kilograms and divide it by your height in meters squared.
(Or if you’re in the USA and laugh in the face of the metric system, you take your weight in pounds, divide it by your height in inches squared and multiply it by 703.)
The formula looks like this:
Like stated earlier, this is a convenient tool for medical professionals because it provides a simple and quick way to categorize someone as being healthy or overweight.
Here is the chart that is used to determine what category of weight someone fits into:
The simplicity of the BMI makes it super simple to look at the world population as a whole and determine where everyone roughly stands in terms of being underweight, healthy, overweight, and obese.
There is, however, one problem when using the BMI...
BMI Doesn't Account For Lean Body Mass
This is easily the most common problem with using the BMI. Since it only looks at height and weight, BF% and LBM (Lean Body Mass) aren't factored in.
Lean Body Mass is everything that isn't fat in your body (muscle, bones, organs, blah blah blah....) Here is an example of what a higher LBM would look like using the BMI scale:
I was around 12% body fat whenever I weighed 180 pounds in mid/late 2012 when this photo was taken
Most people would agree that 12% body fat was a healthy body fat to have as a young adult, and it's pretty clear that I am not overweight, at least not by much of the Western World's standards.
However, BMI told a different story....
According to the BMI Chart above, at 5’11” and 180) pounds I have a BMI of 25.
By BMI standards, I would be considered overweight!
People in the fitness industry often raise their middle finger at people who use the BMI, but like I said earlier, the MAJORITY of the world's population isn't carrying around extra LBM.
On the contrary, they may have less than what is ideal...
BMI May Be Underestimating Obesity
BMI fails to address individuals with high LBM (muscle mass), but its also skewed in the other direction, for people with very little muscle mass.
A study in 2008 by Romero-Corral et al. looked at data from the United States Third National Health and Nutrition Examination Survey. They discovered that when using the BMI, 21 percent of men and 31 percent of women met the requirements for being obese.
However, when looking at those same participants body fat %, they found that 50 percent of men and 62 percent of women were considered obese. (Edelson, 2015).
So not only can the BMI overestimate whether someone is overweight or not, it can also underestimate!
The takeaway here should be that the BMI is inaccurate for people with abnormally high or low amounts of LBM (in comparison to the rest of the world's population.)
On a side note: If the BMI had an enemy, it would TOTALLY be Christian Bale... look how he has swung from one extreme to the other!
If I didn't love literally every movie Christian Bale was in, I would write him a very wordy, detailed letter of complaint...
Now, you may be asking yourself:
"If the BMI is so bad, then how should I track my progress?"
Well, there are a couple of ways that I have found to be much more accurate for tracking your body progress, especially if you are building muscle.
Track Your Body Fat Percentage
Tracking your body fat percentage is much more reliable when determining your body composition. This is because it looks at your lean body mass (LBM).
So someone could be 6 feet tall and weigh 185 pounds but be totally healthy if their body fat percentage is within a healthy range.
The same applies for someone who is 6 feet tall and weights 165 pounds. They would be healthy according to BMI (looking at their height and weight), but their body fat percentage may show they are overweight because they have little muscle mass.
Here is a chart showing what different body fat percentages correlate with being healthy, overweight, etc.:
Track Your Waist Measurement
This route is the easiest and most affordable. It might even be more accurate.
I have found that tracking my waist measurements in comparison to my height to be one of the best ways to track progress.
Fun Fact: There is actually science behind attraction and ratios in the body. This is known as the Adonis Belt.
If you’re a guy and you want to have the "Hollywood Look", you’ll want to have a waist to height ratio of around .44-.45. (for a 72 inch guy, this could be achieved at a 31-32 inch waist measurement.)
As you can see, The BMI is helpful for addressing a large population, but may not be so on a person to person basis.
If you are currently losing weight and working out at the gym, don’t focus on getting to a healthy BMI range. Instead, you should shoot for a healthy body fat percentage, or more simply, a healthy height to waist ratio.
I actually got the idea of tracking my height/weight ratio by following the Kinobody "Greek God" program. In terms of building a great physique, I have yet to find a more simple and effective approach to building lean muscle.
Don't let the name scare you away, building the body of a Greek God doesn't have to be something crazy and unobtainable. Take this photo of Ryan Gosling from Crazy, Stupid Love:
I remember seeing this photo when I was younger and thinking he was freaking ripped! He is definitely in shape, but his physique is absolutely attainable for anyone to achieve.
...and I am not sure of any girl who would say Ryan Gosling has a bad body...
Here's the program if you're interested.