The Truth Behind Your BMI
In the game of optimal health, there’s no real need to get fancy. You can stay honest with yourself by checking a few key parameters on a regular basis. One of which is scale weight, which is also the most obvious, and arguably the easiest.
But then you have Body Mass Index, or simply, BMI. If you want to get even more technical, BMI is a measure of a person’s size that can determine the risk for weight-related disease.
According to the Centers for Disease Control, a high BMI can translate to a high amount of fat on the body. However, this whole concept has holes in it.
If you have been told by your physician that you have a high BMI, do not worry too much until you have more insight into the reality of this measurement.1
How is BMI measured?
First of all, there is a bit more you should know about BMI. Doctors are the ones who tend to use this parameter most often because they are busy and don’t have time to go through the weeds of your body shape as much as say, a personal trainer.
So they sometimes need to make fast decisions as the basis for their assessments on you. This is where the BMI reading comes in. And the way to do the actual measurement is twofold.
There is an actual equation that can be used to determine BMI, which is weight in kilograms divided by height in meters squared. Although this appears to be a simple formula, it is actually tricky since it’s in the metric system.
The easier route is to find a website that has a calculator. In this case, you can choose either the Imperial or metric system, plug in your height and weight, and voila, you get your BMI. The BMI Calculator USA website is a good example.2
A physician will likely use the second method with access to his own calculator.
What are its limitations?
When it comes to the actual end number, there is a chart that is used as a reference. According to the World Health Organization, the ideal BMI for adults is between 18.5 and 24.9 kg/m2.3
It is alleged that, if your BMI should happen to be higher than 24.9, you are at a greater risk for disease. However, there are actually a lot of people who will read high on the BMI, but actually be in great shape.
Just look at certain football players. Or better yet, take bodybuilders into consideration. Someone who takes stage in the heavyweight division at 5’8” with a BMI of 26, might actually be a block of solid muscle. Yet, he will read high.
The problem is that the chart does not take into account lean body mass. In other words, the bodybuilder mentioned above could have a very low body fat percentage with a high amount of muscle.
In reality, he would be otherwise healthy, but the BMI chart would govern otherwise.And there is also one more flaw to be pointed out. BMI does not tell you where the body’s fat is distributed.
Obviously you can see fat on an individual. But without knowing what someone looks like, you would not know if the fat is centralized in the abdomen or more evenly dispersed throughout the body.
That can slightly throw a curveball at doctors, as belly fat is the dangerous type of fat that increases the risk for disease. If the doctor is just reading a chart before seeing a patient, they may assume that the patient is overweight or obese, and have a high amount of fat in the stomach. But when they meet the person, they may see that this is not the case.
Why body fat percentage is more accurate
When it’s all said and done, there’s nothing wrong with using BMI as a quick reference. But due to its lack of precision, body fat percentage is the best way to go. In fact, it's even better than relying on the scale.
This parameter gives you a true reading of what you want to know the most—how much body fat you have in relation to your lean body mass. For reference, lean body mass (LBM) is all the material in your body minus fat, which includes muscle, skin, hair, fluid, bones, connective tissue and so on.
If you have a lower body fat percentage, then your risk for heart disease, diabetes, cancer and all other forms of chronic disease is reduced. And THAT is what you are really after.
- Blog Contributor