Body Composition
By: Mark Shields
Before covering various methods of testing body composition, let’s talk about the scale. Many people track their progress by pounds lost or gained. Imagine this scenario: you weigh yourself and it shows 130 lbs. Now wait a minute! We’re going on a field trip to the moon. We hop in our rocket ship with our scale in hand. Once on the moon you jump on the scale. I think it’s safe to say you weigh less. Did your appearance change? Do your clothes fit better? What is the reason for this, if the scale reads less? The fact is a scale measures your body under the control of gravity. It can’t distinguish if you’re losing water, muscle (which diets do quite effectively), or fat. So why judge your progress on something that can’t possibly tell you how much fat you’ve lost?
It seems the right thing to do is to have your body composition measured (body fat %). Hold on, not so fast. The problem with body composition tests is they’re not 100% accurate. Don’t get me wrong, skinfold measurements, can be extremely valuable in helping you track how much fat you’ve lost and muscle gained.
That is why it’s important not to get focused on the exact percentage you get. This will give you a baseline measurement to compare to later on. Let’s take a young man, we’ll call him Tim, for example. He weighs 185 lbs. Oh no; didn’t I say earlier scales aren’t that smart? Bear with me for a moment. Then he has a skinfold measurement and is estimated at 23% body fat. Six weeks later Tim comes back and is measured again (by the same tester, to insure consistency) and has come down to 182 pounds with 20% body fat. At first glance Tim has only lost three pounds in six weeks. However, after doing some calculations from his first visit (bodyweight x body fat percent) this means Tim was carrying 42.5 pounds of fat on him. After calculating his new measurements Tim has 36 lbs of fat tissue. So, while he has only lost three pounds on the scale, Tim has lost six and half pounds of fat while gaining three and half pounds of muscle. Why is this important? Muscle is the site on the body where fat is burned thus aiding him in long-term successful fat loss.
There are various methods of body fat testing. Each have their advantages and disadvantages. The one most valued by qualified trainers is the skinfold caliper. This is just a handheld device that acts like a pincher to measure the thickness of the skinfold. When done by the same tester it has a high level of consistency. That’s what we’re really going for is a consistent way to track progress.
Another popular method is a handheld device or scale that sends electric pulses through the body (electrical impedance). Electricity travels faster through water than fat and since muscle is predominantly water, the faster the signal returns the lower the reading. However, consistency and accuracy are definitely a concern since hydration levels, sodium intake, and fat distribution can alter readings from one given time to another. However, this method can be useful for those who do not have access to skin-calipers.
Hydrostatic weighing is considered the gold standard for body fat testing. However, this is often an impractical approach. Basically, you’re dunked under water and asked to expel all of the air from your lungs. This can be a frightening experience for most people. Error lies in the fact that not all of the air is expelled plus you can still have air in the digestive tract. Also, not everyone has access to such a facility and equipment.
The important thing to remember is to never rely solely on the scale to judge progress. It can’t possibly distinguish between water, muscle, or fat. Have a qualified trainer perform skinfold measurements, preferably from several sites on the body. Once you have your baseline measurement you will have an excellent way to see if you’re making positive progress. Some of the best ways to track progress are going to be; how your clothes fit, how you look in the mirror, how others see the changes in you, and your increased energy levels.
