Everyone is familiar with the scale. You know, the one you step on to see your body weight. We have been using a scale since before we could even step on one. Everyone is weighed when they are born, and at every check-up after that.
Body weight is used as a health metric in many methods. The most popular metric is the Body Mass Index (BMI). The BMI is a proportion of body weight to body height. In the BMI, numbers correspond to levels of health found in the grid of intersecting body weights and heights.
As we look at this chart, we see the X-Axis is weight and the Y-Axis is height. The numbers in the colored squares increase as you move from the lower left to the upper right. This shows a relationship of decrease in health as the ratio of height in inches to weight in pounds decreases.
This particular example gives us a rich color effect. Moving from the lower-left to the upper-right, we see a change from blue, to green, to yellow, to orange, to red. Interestingly, hazard colors progress this same way, from safe to hazardous.
The BMI assumes an optimal ratio of height to weight. Given any height, the BMI suggests a weight range a person of the selected height should fall in.
Ratios are important to determine a general range for health, but the BMI falls short in two ways.
First, the BMI does not account for density.
Density, in terms of the body, accounts for the compactness of tissues and bone. Both bone and muscle can increase or decrease in density depending on a person’s lifestyle.
Dr. Gordon, my HPE teacher in college, used Adrian Peterson as an example to thwart the accuracy of BMI. Peterson, a future NFL Hall of Fame running back, is 6’ 1” tall and weight 220 pounds. According to the BMI, he is overweight. If we look at Peterson, we do not see someone we would consider overweight. He is very fit with a single-digit body fat percentage. He also has amazing physical health due to the training to stay competitive in the NFL.
The reason Peterson is inaccurately portrayed on the BMI is his high bone and muscle density. He has large amounts of lean muscle mass and a healthy bone structure. AP's densirty throws the ratio off under its assumption of a general correlation between height and weight. The ratio simply does not account for fitness in terms of muscle mass and bone density.
Second, the BMI does not account for body ratios.
Everyone has a ratio of upper body to lower body, torso to arm length, and hip to shoulder width. These anatomical differences account for different sizes of bone and length of muscles. When someone has long legs and arms and a relatively short torso, he or she has a different density potential than someone with a long torso and relatively short arms and legs.
Everyone is shaped differently, and the BMI does not account for these differences. Yes, there is a buffer built into the system, but the buffer just suggests a weight range and does not look at individual build.
Take me for example. I am 5’ 8” and 160 pounds. I am around 9% body fat. The BMI categorizes me as borderline overweight. Yes, I can lose a small amount of body fat, but if I gain muscle mass, I will be tipped into the overweight category.
The problem we face here is psychological. We have used parameters for health measurements, such as the scale and BMI, to dictate health at the psychological detriment of many people.
Many people are fixed on the scale and do not believe change occurs unless the number on the scale goes down. We coach our clients to observe how clothes fit, how much effort is required for daily tasks, and mood improvement as better indicators for progression.
Some even see the scale go up in the first three months. If desire is to see the scale go down, weight gain can be psychologically damaging. The person feels like he or she is going backwards when he or she is dramatically improving health by increasing bone density and muscle mass.
Muscle mass and bone density directly correlate to longer life and better quality of life. Period.
It’s time to go to war with the scale.
Let’s stop using a damaging and inaccurate means for improving health. Get in the gym, get moving, and eat well. Over time, you will learn to use better metrics to see your improvements.