Body composition is an analysis of the percentage of stored fat in a body as compared to lean mass. In this lesson, learn more about body composition and tests to measure it.
What Is Body Composition?
Have you ever thought about your weight? Or perhaps, you've made resolutions to get into better shape. Many people are consumed with issues surrounding weight, obesity, self-image, and health. There is certainly pressure to be thin and look like the celebrities and models who adorn magazine covers. However, an obsession with the number on the scale is often a misguided way of thinking about general health. It is more important to ask, what is that weight made up of?
This is where the concept of body composition comes in. Body composition is exactly what the name states: what our bodies are composed of. Now, it could be said that in a general sense we are all made up of the same parts. It is true that every body contains muscle, bone, organs, tissue, and fat. However, proportionately, fat in particular varies immensely from person to person. And, this is the primary focus of body composition: the percentage of stored fat in a body versus lean mass. In this lesson, we'll take a closer look at this comparison and explore the ways in which body composition is determined.
Fat vs. Lean Mass
Let's take a look at the concept of fat versus lean mass. First of all, it is important to understand the different types of fat in a body. Not all fat is the enemy. Everyone has some fat, and we all need a certain amount of fat for our bodies to function properly, known as essential fat. Stored fat is the culprit. Stored fat is that extra layer of fat that is found under the skin in places such as the stomach and rear end. A spare tire around one's waist is stored fat.
Lean mass is essentially everything else found in a body, including bones, muscles, tissues, and organs. It will come as no surprise that a healthy body has less stored fat and more lean mass. You may be getting a better understanding of why considering only a person's weight is not always an accurate measure of good health. You can put two people side-by-side that weigh exactly the same, but one may have a higher percentage of fat versus lean mass. So, how can you find out your specific body composition?
Tests and Examples
There are several ways to measure a person's body composition. These are non-invasive and fairly accurate assessments. Because body composition measurement involves internal tissues and body parts, there is a degree of estimation that takes place.
The first test involves skin fold measurements. This is a way of assessing amounts of stored body fat under the skin. In this scenario, skin is pinched and pulled outward in specific areas of the body such as the abdomen, thighs, and triceps. Calipers are then used to determine the thickness of the skin fold. You may not have calipers at home, but you can get a general idea of how this works by pinching and pulling on your own abdominal skin. Equations are then used to calculate body composition. This method is considered most accurate for those individuals with an average amount of body fat.
Another method of measuring body composition is a technique known as bioelectrical impedance analysis, which involves passing a very low electrical current through the body to assess the total amount of body water. Since water is a conductor of electricity, the areas of the body containing more water will move the current more quickly. Since lean mass contains more water than fat, fat tissue will be areas that impede the electrical current. From the assessment of total water, an estimate of lean mass versus body fat can be made.
A newer and more high-tech measurement method is called the BOD POD, a structure that looks somewhat like an upright submarine and uses principles of air displacement to determine a person's general volume. Have you ever used water displacement to find the volume of an object? You might have put a block into a measuring cup of water, and you saw the amount of water that was raised indicated the object's volume. The BOD POD uses the same principles. A person sits in the pod, and sensors detect amounts of air that are displaced by the person's body.
Once volume is determined by the BOD POD, mass (or weight) is also found using a very precise scale. Then, density of the body can be calculated using the formula D = M / V. This number is then used to determine the proportions of stored fat versus lean mass in that individual. Finding body composition using the BOD POD is considered to be a very accurate measurement.
In this lesson, we learned about body composition and how it's measured. Body composition refers to the amount of stored fat in a body compared to the amount of lean mass. Stored fat is extra, nonessential fat. Lean mass, on the other hand, includes muscles, bones, organs, and tissues.
There are several ways to measure body composition. Skin fold thickness tests involve pinching skin and measuring the thickness of the skin fold. Bioelectrical impedance analysis involves running a low electrical current through a body to measure total body water. The BOD POD is a device that measures body volume, which can then be used to find density. All of these tests use additional calculations to find total body composition.