Methods Of Calculating Body Composition

By: Nick Izzo

Hey readers! Today I’m going to talk to you about the many ways body composition can be measured. The technique used depends on the availability of equipment, how well the staff is trained, the condition of the patient, location where the assessment will be done and also how much the assessment will cost.

One of the most basic ways to measure body composition is girth measurement. The only piece of equipment required is a tape measure. You take the measuring tape and measure your fat sites and muscle sites. So this includes stomach, arms, legs etc. A prediction equation can be used with the numbers you find to assess your body composition. Some problems with this technique is that the user has to be very consistent with measuring which can take some skill. Another issue is the areas you measure may not correctly depict fat distribution since everyone has their weight distributed differently. Although this method has some flaws it does provide pretty accurate estimations. Another way to measure body composition is BMI or Body Mass Index. This is the most common way and the one used by your doctor at your yearly check-up. A quick side fact about this technique is that it was invented by insurance companies in the 1940’s solely based on mortality statistics. They found that people with a higher BMI the more likely they were to die. This method is very simple to use; it only involves plugging in two numbers into a very simple equation. You take your weight, in kilograms, and divide that by your height squared, in meters. This method is proven to be just as accurate as the more costly and advanced methods. One issue with this technique though is it tends to over-estimate very muscular individuals. This is because their weight could be high but that’s because they have a lot of muscle, not a lot of fat. One interesting way of measuring body composition is hydrostatic weighing. This finds the density of the body which can be calculated to find percent body fat. This method uses Archimedes principles. This states that if the amount of buoyant force on an object is equal to the amount of water it displaces then you can divide a person’s body weight by the difference in body weight in air and underwater. This will determine the percent body fat an individual has. As accurate as this method is though, there are many issues with it. This technique requires specialized facilities which can be hard to come by. Also, when you are submerged underwater, you have to exhale as much as possible from your lungs. This can be very uncomfortable for the person being assessed which sometimes means people will opt out of doing it. Lastly with this method, it is very expensive and time consuming. So in the end why spend a lot of money and time on one method when using the BMI method is almost as accurate, costs virtually nothing and doesn’t take up nearly any of your time?

Here is hydrostatic weighing in action:

It's very important to find a method that works for you. If you have the money and time and are comfortable with being fully submerged under water for an allotted time then hydrostatic weighing is the method for you. If you want something more comfortable, affordable and less time consuming then BMI and girth measurement are very reliable methods. There are many more methods than the three listed and they all have their positives and negatives. Depending on cost, time and accuracy finding a method suitable to you shouldn’t be all too difficult.

References:

"Archimedes' Principle." Wikipedia. Wikimedia Foundation, 23 Mar. 2017. Web. 26 Mar. 2017.

“MSU- KIN 173 – Foundations of Kinesiology – Spring 2017”. Education.msu.edu. N.p., 2017. Web. 15 Feb. 2017.