To Explain what Body Composition is and how to measure it, we have to look at what it replaced and why that was not working accurately enough.

Body Mass Index (BMI) - The Outdated Method

Body mass index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. It is determined by dividing a person’s weight in pounds (lbs) by their height in inches (in), squared and then multiplied by 703.

The formula: BMI = weight / [height (in inches)]2 x 703

A healthy BMI is considered to be between 18.5 and 24.9 kg/m2. If you have a BMI of 25 to 29, then that’s considered to be overweight. At a BMI of 30 or above, you are considered to have obesity. Refer to the chart below to see what your BMI is.

Why is BMI so commonly used, and what are its shortcomings?

It estimates body fat based on a person’s height and weight, and does not take into account age, genetics, race, muscle, or fat distribution.

The important thing to understand is that it’s not just excess fat that affects a person’s BMI. So equating BMI with body fat is not a good practice.

Muscle mass: For individuals with more muscle mass, (Athletes, BodyBuilders) BMI isn’t a good measure of body fat. They may have a “higher than normal” BMI due to the increased density of Muscle
Age: People tend to lose muscle mass and gain fat as they get older. Because of this, older adults’ BMI often suggests that they have lower body fat than what they actually have.
Sex and race: BMI was created using data from Caucasian (white) men, so the scoring does not work as well for women and non-white people. Women often have more body fat than men with the same BMI. In Black people, BMI often overestimates body fat, while in some Asian people, it commonly underestimates body fat.
Fat Distribution: BMI also doesn’t tell us anything about where the fat is located. This is an important shortcoming, since it is clear that people with fat around the middle abdominal area (visceral fat) have a greater risk of health problems than people with fat in their arms, bottoms, or thighs.

Body Composition - The New Method

Body composition refers to the two different types of mass that your body is made up of, body fat and non-fat mass.

Body fat - is located around your organs (which is known as visceral fat) or under your skin (subcutaneous fat).

Non-fat mass - refers to the rest of your mass that isn't fat, including muscle, water, bone, tissues, and organs.

Why is Body Composition Important?

Body composition is the best way to tell if you are losing body fat or gaining muscle.

Oftentimes people will find that they aren’t losing weight early into their health and fitness journey, which leads to frustration and giving up. This is common if you rely on the scale as the best way to measure weight loss. However, the scale doesn't give you the full picture. Just because you aren't losing pounds doesn’t mean you aren’t losing fat. More often than not, you are experiencing changes in water weight or potentially gaining muscle and losing fat at the same time. This is where body composition testing comes in clutch.

The scale can tell you how much you weigh, but body composition tells you where that weight is coming from (aka fat, muscles, or bone).

What is a Healthy Body Composition?

A healthy body composition depends on your gender, age, and fitness level. The "normal" range can also vary depending on the accuracy of the body composition assessment you choose. Generally speaking, you can use the following chart to assess your body composition status.

Blue - Below Average

Green - Average

Orange - Overweight

Red -Obese

In Summary, The Old method of BMI was not a reliable enough way to measure body fat. Even though it has been used for many years, it is far from perfect containing no adjustment for age, genetics, race, muscle, or fat distribution it can give wrong impressions about total body fat when used incorrectly. Body composition tells individuals the exact makeup (Body fat vs non-fat) that their body contains. It is a more reliable way to see exactly what percentage of your body is Fat mass.

Measuring Body Composition

There are multiple ways to Measure Body Composition. We will go over a few here, noting some of the Pro’s and Con’s of each.

Tape Measure (US Navy Circumference Method)

A Tape Measure is one of the most affordable ways to measure Body Composition. The US Navy Circumference method helps estimate body fat percentage by taking the circumference of certain areas of the body using a soft tape measure, and then plugging those numbers into a formula.

What formula, and body parts, you measure will be dependent on your sex.

Women

Body parts: neck, waist, and hips
Formula: 163.205 x log10(waist + hip – neck) = 97.684 x log10(height) – 78.387

Men

Body parts: neck and abdomen
Formula: 86.010 x log10(abdomen – neck) – 70.041 x log10(height) + 36.76

A calculator can help with this. Here’s one from the U.S. Navy to get you started.

Tape Measure Pros

Affordable way for anyone to get their estimated Body Composition.
Easy to Find at multiple stores.

Tape Measure Cons

Can be difficult to measure your own body, You might want an extra set of hands.
With Calculations, there is always room for User error. Double Check your numbers!

Skinfold Tests

On the market there are many devices that can Measure Body Fat using the Skinfold Test.

Below are a Few Examples of some Calipers that we have at Fit-Lab:

Perhaps the most accessible method for measuring body composition, this method uses skinfold calipers to pinch the body in specific areas to measure the skinfold thickness. This can be done through a 3-point measurement or 7-point measurement. These measurements are then combined with a person's age and gender are input into a specific formula to provide a percent body fat estimate.

While a skilled person with a decent knowledge of anatomy can guesstimate a fairly accurate body fat percentage this way, an unskilled person might end up being much less accurate.

Using skin calipers is the cheapest and most accurate method for average lifters to check their body fat percentage. However, it requires a skilled individual to make correct measurements. It requires a person to use calipers to measure the amount of fat in various areas of the body. In order to get an accurate reading, multiple measurements will need to be taken from different spots. This is because different people store fat differently, so taking various measurements will correct this as it will give a better picture.

Skinfold Test Pros:

Relatively inexpensive: Calipers are around $10 per pair and can be used again and again.
Accessible: Can be completed anytime or place.
Speed: Test is Quick and Painless
Attire: You can wear normal Workout clothes (Shorts and T-Shirt) while getting measured
Simplicity: Just Use the tool, Write down the measurements. No settings or machines

Skinfold Test Cons:

Accuracy: Body fat distribution can factor into the accuracy of each site.
Human error: It takes practice to get consistent results.
Repeating: Each Site should be measured 5-7 times and then averaged. With 7 Sites that can be 49 Measurements. The most important thing is to use the exact same spots every time.
Partner Friendly: It is strongly encouraged to have a buddy to help you measure, meaning that its more difficult to do alone.
Limited: It only measures subcutaneous fat (fat below the surface of the skin) and does not do a full body assessment. Not everyone stores fat in their body the exact same way.

BIOELECTRICAL IMPEDANCE ANALYSIS (BIA) Tests

Bioelectrical Impedance Analysis (BIA) uses a low electric current that travels through the body to estimate fat free mass.

Since electricity can only travel through water, and each bodily tissue contains varying amounts of water, the flow of the electric current is impacted by the conductivity of each tissue type. For example, muscle holds more water than fat, so the flow of the current becomes less interrupted (low impedance) when a person has more lean mass and more interrupted (high impedance) when they have more body fat.

BIA Pros:

Painless: The current is low enough that it does not “Shock” you
Many types of BIA tools available: Bathroom Scales, Portable machines and handheld devices.There are also more advanced BIA machines that use electrode placement on the body.
Inexpensive: You can easily get an at home BIA scale or handheld machine for $30 to $50 and perform a body comp test any time you need.
Easy to Operate: Users need little to no previous practice, Since this technique requires little more than pressing a button.
Quick: Measurements can be done in a matter of seconds.

BIA Cons:

Not always Accurate: Depending on food and fluid intake the measurements can vary.
Not Viable after workout: Exercising can effect the Results
Margin of Error: for BIA body composition analysis is 3-8%, however this number is likely increased when using at home scales

For the most consistent reading, take readings at similar times during the day in the same conditions.

3D Body Scan

3D body scanning is another method that you can measure your body composition. This equipment utilizes infrared sensors in order to generate a 3D model of your body. This method has the individual either standing on a rotating platform or standing still while sensors rotate around the body.

3D Body Scan Pros:

Accuracy: A typical tape measure can only offer 0.5-1 inch accuracy and repeatability, whereas a 3D body scanners can have errors as low as than 0.1 inches.
3D Visuals: Make a difference in helping people visualize their shape and how it may be responding to your fitness or training program.
Easy to track Progress: You are able to Scan every day, allowing you to frequently track your progress and find small changes you wouldn’t normally notice.
Multiple products: There are different scans on the market that come at varied prices.

3d Body Scan Cons:

Clothes: You have to wear tight, Form-fitting clothes for the most accurate scan. Same Clothes recommended for comparison
Hair: Hair has to be up and out of the way for proper measurements.
Movement: You have to remain still during the process (As you spin around) for the most accurate results.

In Summary, There are multiple methods to determine Body Composition. With all of the methods on the market everyone should have some indication of their Body Composition. Choose the best or most accessible for your needs/location. Once you have the data, you can track progress towards your Health and Fitness goals!

If you are near Fit-Lab and want to try out the different methods, Book an Appointment Today

~Christopher

What is Body Composition and how to measure it?