Body Fat Calculator: Measurement and Control

There are several ways to determine your body composition. You could step on a scale with a body fat calculator function or use record some body measurements and do a little math to determine it yourself. Measurement is important for determination of body type, which is, in turn, key to the setting of realistic goals and control of body fat which is, in turn, important for determination of progress and sustained good health.

Body Types

Dr. William H. Sheldon proposed his somatotype theory in the 1940s. It held that there are three basic body types, or somatotypes:

  1. Ectomorph
  2. Mesomorph
  3. Endomorph

Each of these types defines a structural profile based on

  • height,
  • weight, and
  • skeletal measurements from several different regions of the body.

Ectomorphs have a comparatively short upper body with narrower shoulders and shallower chests; longer neck, arms and legs; and very little fat storage with thin muscles. Ectomorphs have a more delicate bone structure with shoulders and hips that are approximately the same width. They will usually have a very hard time gaining any kind of weight, regardless of whether it’s fat or muscle, despite eating high-calorie foods at any time in large amounts.

Mesomorphs have larger chests and longer torsos, shoulders of greater breadth than hips, and solid muscle structure set on moderate sized bones. Mesomorphs can gain and lose weight, either from muscle or fat, without much trouble and their fat storage is moderate.

Endomorphs exhibit a generous but softer musculature, bigger bones and joints, thicker hands, a fuller face, and higher fat storage. These curvy mean and women often have hips at least as wide as their shoulders. Persons with this body type generally have a hard time losing excess body fat.

Make the Best of It

Our body structure is based on the genetic blueprint assembled from our parents’ DNA; our basic body structure will never be changed by diet or exercise. Sheldon’s theory has since been refined and we know most people exhibit characteristics of more than one of the body types, i.e., endo-mesomorphic, ecto-endomorphic, and so forth. One thing hasn’t changed: all we can control with diet and exercise is our body composition, that is, the amount of fat on our bodies versus the amount of muscle. This being the case, we must all make the best of our body form’s structural design.

To achieve your desired results, it is so important to evaluate your body type and proceed with your workouts accordingly. Many strive to be as mesomorphic as possible because this is overall the most robust, healthy, and fit type. It may be difficult but, with the proper diet and plenty of exercise, it is not impossible to change your body composition and maintain a more mesomorphic condition.

Body Fat Calculator Options

The most accurate, if not the most accessible and cost effective, ways to determine body fat percentages are through a dual energy x-ray absorptiometry (DEXA) scan or through hydrostatic weighing.

Dual energy x-ray absorptiometry (DEXA) scanning is an expensive clinical method using low energy x-rays passing through bone, fat, and lean tissue. Hydrostatic weighing calls for a water immersion tank to capitalize on Archimedes’ displacement principle.

Two reasonably accurate and reasonably common ways to determine body fat are bioelectrical impedance and pinching of skin folds with calipers.

Bioelectrical impedance is the principle used by the integrated body fat calculator on some household and commercial, digital scales. Impedance is opposition to the flow of electric current. The impedance of a person’s body can be measured by passing a small current through the feet. Impedance will vary depending on the body’s percentage of fat compared to muscle and other tissue as well as bone. The scale should include the specific instructions on how to use the function; but, the basic process is to enter a few important body measurements before stepping on the metal contacts of the scale.

Pinching of skin folds with calipers is very simple. A pair of calipers is used to grab hold of loose flesh like the “love handles” around the waist. Pinching of skin folds with calipers is also inexpensive and accurate; some caliper manufacturers claim to be within 1.1 percentage points of hydrostatic weighing results! Calipers can be purchased through a retailer and most personal trainers at a fitness club will have a pair. The reading on the calipers is then compared to a chart for a determination of body fat.

For anyone not standing on a body fat calculating digital scale or in possession of calipers, there is a manual method. It is the least expensive but still delivers a good estimation of body fat. With a tailor’s tape – one of those highly flexible measuring tapes for fitting clothes – in hand, some paper, and a pen or pencil, you can be your own body fat calculator.

Taking Measurements

To figure out your body fat, you will need to take few simple measurements and then perform some easy math.

Start by standing with your feet slightly less than shoulder width apart. Relax and breathe normally. Measure the following:

  1. X1, the circumference of the middle of your upper arm as it hangs extended and relaxed by your side
  2. X2, the average circumference as measured from two points at your waist, the first being around the belly button and the second being the abdomen at its smallest part (i.e., skinniest part around your stomach; this should be somewhere above your hips and below where your ribs fully connect at the front of your chest); let’s say 30 inches when taken around the belly button and 28 inches when taken at the skinniest part, so the X2 would, in this example, be 29 inches
  3. X3, the circumference of your forearm at its widest part as it hangs with your palm facing forward.

Take this last measurement as well if you are a woman:

  1. X4, the circumference of the top of your thigh a half inch below your buttocks

These measurements will be useful for entry into a body fat calculator built into a scale as well as formula that can be resolved on paper.

Calculating Body Fat on Paper

If you’re like most Americans, you measure everything using English units. In that case, you will need to convert the measurement from inches into centimeters. Remember, 1 inch is 2.54 centimeters.

Plug your measurements (in centimeters) for the variables X1 through X4 into the body density formula for your gender.

The body density formula for men:

D=1.12619-(0.00357 * X1) - (0.00127 * X2) + (0.00524 * x3)

The body density formula for women:

D=1.4465-(0.0015 * X1) -(0.00105 * X2) + (0.00448 * X3) - (0.00168 * X4)

When you have a value for body density, Db, plug your body density value into Josef Brozek’s formula for body fat percentage:

% Fat = 457/ D - 414.2

The limitation of the formulae and other like them (Siri’s, Schutte’s, Wagner’s, etc.) is that they are based on the assumption that the density of fat-free mass remains constant across a diverse population of people. In reality, it varies. In other words, a young and athletic person will tend to have bones and muscles more dense than an old and/or infirm person, which may lead to an underestimation of body fat percentage. The old and infirm, in contrast, may have comparatively porous bones and soft muscles, and that can lead to an overestimation of body fat percentage.

As a body fat calculator, the formula provide reasonable estimates. If you want more precise and more convenient measurement means and results, you might consider investing in calipers or a digital scale.

Add Comment

0 Items