I have found that there is one constant in the exercise world. Regardless of gender, age, goal, or training status, e’erbody wants to know their body composition. Like, seriously, everyone. I have worked in several gyms and it is common for personal trainers to offer periodic events that are open to anyone and are free. Bar none, the best attended of these events are always when the body fat analyzers come out. Every single time I have held one of these events (or watched one of my staffers), I answer the same questions. Every. Single. Time. So, in this two part series, I bring to you the run-down of what’s what in defining your body composition.
Before I get started with the nitty gritty, though, a little bit of background. When we as fitness pros refer to body composition, we are referring to the relative amounts of lean tissue versus fat tissue that comprise your body. I think we all know that less body fat is better, but to a point. All of us need a certain amount of body fat to function. Fat is an important component of both our nervous and endocrine (hormone) systems. Some fat is also necessary to provide cushioning for our organs and so that certain vitamins and minerals work properly. Ladies, thanks to our awesome ability to conceive, grow, and nuture tiny humans, we need more body fat to help support those functions.
The other important thing to keep in mind about body composition is that the term “measuring” should be used with quotes. In other words, even on the best day, you are getting an estimate. And different methods might result in different estimates. Just as you (hopefully) do with the scale, please don’t let one number one time send you in to a shame spiral. You want to be aware of trends (i.e. are you holding, going down, or up?) Keep in mind that there is only one way to EXACTLY know your body fat percentage and it involves some Hannibal Lector style dissection and tissue classification. Ouch, and gross.
So, now I think we are ready to dive in. I am going to cover the two most commonly used methods to “measure” body composition in gyms or rec settings.
- Skinfolds or the Caliper Method. In this method, a fitness pro will mark several spots on your body. Sometimes three, sometimes seven. These spots are then pinched and the thickness of the skin is measured with a small machine or caliper. We know that between 1/3 to ½ of our body fat lies directly under the skin. Gives new meaning to the pinch an inch adage, doesn’t it? The thicknesses are added and that number is plugged in to a honkin’ long formula with your gender, age, and weight to estimate body fat percentage.
- Bioelectrical Impedance Analysis or the Body Water Method. In this method, said fitness pro will use a small machine to measure body water. Lean tissues (muscles, organs, nervous tissue, etc) need a lot of water to function properly. Fat does not. The machine, sometimes a scale-type device you stand on sometimes a hand held device, sends a very low level electrical current into one side of your body and clocks how long it takes to come through the other side. Why? Water conducts electricity well (same reason you shouldn’t stand in a puddle during a lightning storm), so the faster the current runs, the less body fat you have in theory.
OK, so you’ve been pinched or shocked and you have your body composition number, or your percentage of body fat. Now what? Again, please remember that at best this is an estimate. It is more important to look at what this number does over time. I usually recommend “measuring” body composition once per month. Anything more frequent is just showing you fluctuations and is bound to cause more stress than is necessary (just like getting on the scale every day will). Try to replicate the same situation, in other words, same time of day, same pre or post workout conditions, same amount of fluid intake, etc, for the best tracking info.
And because I know you are wondering what the ranges are, here is a handy little chart based on gender and age.
Stay tuned for installment two, when I will tackle common measurements that usually occur with body composition, but are actually very different.
