A body fat test is a great tool for determining your fitness profile. It provides baseline data on which to measure the quality and progress of your workouts, diet, and lifestyle. Ultimately, it will help boost your motivation and training efficiency.
What is a Body Fat Test?
A body fat test measures your fat mass divided by your total body mass. Before I discuss the importance of this, let’s look at the components of this equation.
Your fat mass is generally divided into two categories: essential fat and storage fat.
Essential fat is necessary for many aspects of your health and survival. It’s critical to organ function, cellular development, immune responses, and other biological tasks. Low levels of essential fat have been linked to memory loss, vision problems, mood swings, and ultimately organ failure (PubMed).
Storage fat (also called nonessential fat) is the type that develops when you eat too much pizza. A certain level of this fat is beneficial, as it provides energy, insulation, and protection. This is especially important for athletes. That being said, too much storage fat will put you at risk for a myriad of health and appearance issues (NIDDK).
Total Body Mass
Your total body mass refers to every component of your body (including your fat mass). Water is the largest component. On average, it represents nearly 60% of a person’s weight (USGS). Other components include muscles, bones, connective tissues, and organs.
What About BMI?
You’ve likely heard the term BMI, which stands for Body Mass Index. This is typically the source of popular statistics like “more than one-third of U.S. adults are obese”. The BMI is also used by medical professionals during routine check-ups. If you’re curious, you can calculate yours through the CDC.
BMI is a popular tool because the formula is simple and based on accessible information (height and weight). For this reason, it’s often used by organizations that are attempting to estimate the health of an entire population.
However, the BMI has many shortfalls. Most importantly, it does not distinguish between healthy weight (i.e. muscle) and unhealthy weight (i.e. fat). Therefore, someone who has significant muscle mass (and is otherwise healthy) will likely be considered as overweight or obese.
As an example, Jay Cutler of the Chicago Bears has a BMI of 29.1 (6’3 / 233 lbs). He’s a healthy, professional athlete, but the BMI classifies him as overweight. For this reason, a body composition test is the most reliable option for assessing your individual profile.
Interpreting Your Body Fat Test
Interpreting your results can be a little tricky, as several variables impact a person’s body fat percentage. These include gender, age, fitness level, and even genetics. As a result, there is no “ideal percentage”.
That being said, you can get a general indication by comparing your results to the following table. You’ll note a significant difference between men and women. The primary reason is that women need extra fat to support the child birth process.
While this table might satisfy your curiosity, a body fat test is best used as an indicator of your progress. In other words, don’t worry about comparing your percentage to others. Rather, use it to establish a baseline on which you can measure individual progress.
Before we dive into the four testing types, I want to mention two things that will help you achieve the best results:
First, consider scheduling multiple tests throughout the year. While a single test may satisfy your curiosity, it doesn’t offer the ability to measure progress, customize your workouts, or other key benefits. Many services in Chicago provide discounted packages for this purpose.
Second, it’s important to recreate the same circumstances of each test. Target a consistent time of day, water intake, food intake, etc. Otherwise, these factors may impact your results from test to test.
The skinfold test is the most traditional method of determining body composition. In this test, calipers are used to measure the width of certain areas of your body. These include the triceps, thigh, abs, and chest. The measurements are then plugged into a formula that calculates your body fat percentage.
The skinfold test is very popular, as it can be done by yourself, in any setting, with minimal equipment. However, the results are largely dependent on your ability to perform the test and interpret the results. For that reason, the margin of error is ±3%, which is higher than other body fat tests (UAA).
If you’d like to perform the test yourself, you will need the resources below. Otherwise, you can ask your local gym or personal trainer if they provide this test. Most services are about $20.
- Calipers. These generally range in price of $10 to $300 and are easily found on Amazon.com.
- Test guide and formula. This information is usually contained in the caliper manual. Otherwise, you can refer to the operator guide provided by Beta Technology.
The skinfold body fat test will take approximately 30-45 minutes to perform and interpret.
This test is often considered the gold standard of body composition tests. The procedure consists of the following steps.
- Your weight is measured on dry land.
- You are placed in a large tank of water and positioned on a special scale.
- You are lowered underwater and asked to expel the air out of your lungs.
- At this point, a technician will determine your body fat percentage based on the Archimede’s principle. In simple terms, your fat “floats” and the rest of your body sinks.
This body fat test is reliable and accurate, with an average margin of error of ±1.5% (GSU). However, it is time consuming and may cause anxiety in some individuals.
UIC Human Performance Lab in University Village offers this service for $45. In addition, the facility provides fitness assessments to measure flexibility, strength, lactate threshold, and resting metabolic rate.
Air Displacement Plethysmography (ADP)
ADP is the technology behind the Bod Pod. The science of this technique is similar to that of hydrostatic weighing. The machine uses a series of pressure changes between two chambers to accurately determine body fat percentage.
The Bod Pod usually agrees within 1% of hydrostatic weighing tests (BYU). It’s slightly more expensive, but only takes 15 minutes and doesn’t require you to get into a tub of water.
East Bank Club on the Near North Side provides a Bod Pod test for $65. The gym also has technology to measure VO2 max, fat burning efficiency, and other health indicators. The total package is $300 and includes a personal training session.
DEXA is a relatively new technique in the field of body composition. It uses x-rays to determine body fat percentage, fat mass, bone mass, and lean mass. These calculations are generally available for each region (arms, trunks, and legs).
The procedure is simple and quick – you just lay on a table for about 10 minutes while the machine scans your body. The test has a similar margin of error to the other techniques, but provides much more information. That being said, it’s usually the most expensive option.
DexaFit in Lakeview provides a scan for $100, in addition to other services such as VO2 max and resting metabolic rate. They also offer discounted packages for a full assessment.