Introduction to Body Composition

What Is Body Composition, And What Is Yours?

When judging the health of your physical body, many turn to superficial stats, like body weight and BMI.

But, these don't take into account what is actually making up your entire body. For example, if you take the Body Mass Index on a sedentary individual that weighs 200 lbs and a professional athlete that weighs 200 lbs, their BMI will be the same, assuming they are the same height.

See Related: Body Analyzer Scales

man climbing stairs

Clearly, these two individuals don't have the same body composition. For the sake of argument, they don't have the same health risks either.

Measuring your body composition is a better way to judge your health than simply stepping on the scale to read your body mass or calculating your weight-to-height ratio.

To get a good idea of your own body composition, getting your body fat percentage tested, through various means, is the easiest route.

Body Composition and Body Fat Percentage

dumbells and timer

While there are quite a few different tissues and substances that make up your physical body (organs, connective tissue, bones, water, etc) the most useful measurement for body composition for general health purposes is most likely your body fat percentage.

See Related: Does Muscle Weigh More Than Fat?

This is a simple measurement that accounts for the amount of fat on your body in relation to your total body weight. For example, a 150 lb individual with 20% body fat has 30 lbs of fat and 120 lbs of fat-free mass. In the human body, the weight of bones, liquids, and other tissues may fluctuate, but getting a good idea of how much body fat you have is a good indicator of health.

While it is true that BMI and waist-to-hip ratios are good enough indicators of disease risk, like heart disease, they fall short for those who have an above-average amount of muscle mass. For those of us interested in body recomposition, we are looking to put on muscle and lose body fat. This may mean the number on the scale doesn't even change. While your BMI calculation wouldn't change, your health risks would surely drop!

Factors Affecting Body Composition

two women planking

For the sake of this article, we are going to leave out a few factors that affect your body weight and composition:

  • Hydration levels & total body water
  • Bone mass¬†and bone¬†density
  • Blood volume
  • etc

We are simply going to look at putting on lean body mass through the accrual of skeletal muscle and losing subcutaneous fat through weight loss efforts. Doing these two things is known as recomposition. They can be performed at the same time or in alternating phases.

Percent Body Fat (PBF)

Perhaps the most common of body composition measurements is to find your body fat percentage. There are various ways to get this tested, all to varying levels of accuracy. It is simply the measurement of how much fat you have in your body.

Research has shown that high levels of body fat increase risk factors for all-cause mortality. Interestingly enough, this same study showed that low levels of BMI increased health risks as well, showing the importance of having healthy levels of muscle mass to go with healthy levels of body fat. Someone with a seemingly normal weight (aka "healthy") may not be so healthy after all.

This linked relationship shows how important recomposition is. For those suffering from obesity, it's best to lose fat and gain muscle for the best health benefits. For those who carry a little too much body fat but have a low BMI, gaining muscle and losing fat is the best path to better health. The pattern starts to show itself through the data:

Gain muscle and lose fat for better overall health!

Skeletal Muscle Mass (SMM)

So, we know that losing excess adipose tissue is a good way to get healthier. We also know that gaining skeletal muscle is just as healthy. Unfortunately, measuring your skeletal muscle mass isn't as easy as taking your body fat percentage. Most methods of measuring body fat don't delineate the rest of the tissue and it's simply labeled as fat-free mass.

However, fat-free mass is muscle, bones, water, and everything else in the body that isn't fat. So, if you somehow gain 5 lbs of water overnight and recheck your body fat percentage, your lean body mass appears to have gone up 5 lbs. But, that clearly isn't muscle mass.

One of the few reliable ways to measure your actual muscle mass is through an MRI, or Magnetic Resonance Imaging. Most other measurements are simply guessing at the amount of muscle mass you have.

Luckily, following the trend of lean body mass accrual through other measurement methods can show muscle gain over time, as you wouldn't expect to slowly gain lbs of other tissue in your body

Healthy Body Composition

Healthy body composition is truly dependent on the individual. However, many organizations have put together handy charts for those who want to get straight to the point. For example, Ace Fitness has a handy body fat percentage chart with average ranges in different categories.

Those seeking to be healthy should aim for the Fitness and/or Acceptable ranges. The Athlete range can approach unhealthy body fat levels that can alter hormone balances in the body if maintained for too long and the Obesity category is too high for a healthy body.

Females generally need about 7% more body fat than their male counterparts for hormone balance and general fat distribution differences between males and females.

The older you get, the higher your body fat percentage can be while still being considered healthy. That is because losing muscle as you age is a natural process. Adding

Methods of Body Composition Analysis

There are quite a few methods of measuring human body composition, including:

  • BIA, or Bioelectrical Impedance Analysis
  • Skinfold¬†measurements with Calipers
  • DEXA scans (aka DXA), or Dual-Energy X-Ray Absorptiometry
  • Air Displacement Plethysmography/BOD POD
  • Body circumference measurements
  • Hydrostatic weighing

All of these can be used to measure the amount of body fat and fat-free mass. Some can also measure bone mineral levels, body density numbers for various tissues, visceral fat, and much more.

While all of them can be used to track progress when losing fat and gaining muscle, the DEXA scans are touted as the gold standard for precision and accuracy. That's not to say that the rest are useless to take a body fat measurement, however.

All of these are useful for anthropometric data that can show trends of lowering levels of body fat and rising levels of lean body mass, which is the most important factor towards bettering your health. Knowing your body fat percentage as accurately as possible is nice, but knowing you are making progress towards recomposition through body composition changes is the true goal, which all of these body composition measurements can do.

Simply take a baseline measurement using your preferred measuring method and track regularly to ensure rising amounts of lean tissue and lower levels of body fatness. This will show positive progress, even if the scale hasn't moved up or down and you don't yet see changes in your whole body.

How To Recomposition

Those looking to reduce risk factors for serious ailments like cardiovascular disease, type 2 diabetes, and more should aim for body recomposition at all times. In simple terms, you want to combine muscle gain and fat loss.

The first step is to follow a proper diet, whether it be a clinical nutrition program or a healthy program you find online. You need to ensure that you are eating the right amount of calories, macronutrients, and micronutrients to allow for muscle gain and fat loss.

Next, you have to increase your physical activity levels. Resistance training is the most efficient way to put on lean tissue and aerobic training is a great way to boost fat loss. Using both in an exercise program will boost your fitness level the most.

As you gain muscle and lose adipose tissue, your total body fat percentage will steadily drop. Even gaining muscle without losing fat helps to lower your body fat percentage.

For example, a 150 lb individual with 20% body fat has 30 lbs of fat and 120 lbs of lean body mass. Say that person gains 15 lbs of muscle over time but doesn't change their fat mass. Now they are 165 lbs with 30 lbs of fat, meaning their body fat percentage dropped to about 18.2% body fat, all while gaining weight!

Or, if that individual used body recomposition effectively to lose 10 lbs of fat and gain 10 lbs of muscle while staying at 150 lbs, they went from 120 lbs lean body mass and 30 lbs of fat to 130 lbs of lean body mass and 20 lbs of fat, dropping their body fat percentage to 13.3% body fat with the number on the scale never changing!

Hopefully, it's clear now that putting on muscle and losing fat through recomposition is the best path to better health and longevity.


What is the difference between body weight and body composition?

Body weight is simply a measurement of your total body mass, while body composition shows the amounts of various tissues in your body, including skeletal muscle mass and adipose tissue.

How can I test my body composition at home?

Skinfold calipers and BIA devices like the Dara scale and handheld units that send an electrical current through your body to measure various tissues are the best choices to measure body composition at home. Calipers can be difficult to do by yourself, so BIA devices are usually preferred for ease of use. Electrodes are used to penetrate the body with electrical current to measure resistances from varying tissues in the body, including body fat.

How can you improve your body composition?

A well-rounded nutrition program, resistance training, and aerobic exercises all play a large role in improving your body composition through gaining muscle and losing fat.

What is a healthy body composition?

A healthy body composition features adequate amounts of muscle mass to not score low on the BMI scale with a body fat percentage that doesn't fall above the Fitness/Acceptable level through the ACE Fitness chart.

About Milo: Milo Martinovich is a freelance writer with years of professional experience in the fitness industry. In late 2012, he became certified as a Fitness Trainer and Specialist In Fitness Nutrition through ISSA and opened up a personal training studio with his soon-to-be wife. Read More