Measuring fat percentage

Geschatte leestijd: 10 minuten When you are engaged in fitness or strength training, you quickly come into contact with the term: body fat percentage. But even when you want to lose weight or are simply conscious about your health, then body fat percentage is probably not an unfamiliar term or number. A common question is: how can you measure your body fat percentage? Measuring your body fat percentage can be done in various ways. There are different methods where the body fat percentage is measured with a skinfold caliper and special scales. Below you can read more about measuring body fat percentage.

Body Weight

Measuring body fat percentage is a precise way to determine the body composition. The most commonly used number for measuring someone’s health is still body weight. But in fact, the number on the scale says very little. It’s a composite number of everything contributing to your body weight: bones, fluids, muscle mass, and fat mass. No distinction is made between these variables. This way, someone with higher muscle mass can easily weigh too much. Another number that takes into account someone’s height is the Body Mass Index, also abbreviated to BMI.

Body Mass Index

One of the most well-known terms for expressing weight in relation to height is the Body Mass Index, or better known as BMI. The Body Mass Index is an index number where the weight is expressed based on the individual’s height. Based on the outcome, you are compared to an average group, and there is a good chance that you will end up at the top or bottom of that group. The BMI number also says nothing about the composition between muscle mass and fat mass. However, BMI is still used as an indicator of overall health. So, in news reports where the Dutch population is classified as overweight or not overweight, BMI is still used as a benchmark. BMI is probably still widely used because of its simplicity of calculation. If you want a better understanding of your body composition, measuring body fat percentage is a better approach, where you can calculate lean body mass.

Why Measure Body Fat Percentage

To get a better understanding of body composition, body fat percentage is a better measure. Body fat percentage says more than body weight or Body Mass Index. When you are specifically training towards a physique, you want to measure your progress as accurately as possible. If you want to lose weight, you also want to know if you are actually losing fat or just losing water.

Best Method to Measure Body Fat Percentage

The only time you can measure your body fat percentage accurately is when you no longer care. This can only be done accurately when you are dead and the amount of fat in your body can be determined exactly. Apart from that, there is no method that is entirely accurate. Therefore, it is best to use two different methods, which in practice makes it more difficult again [2]. The most important point to take into account is that there is no “gold standard” for measuring body fat percentage in living people. The problem with all other methods is caused by two things [2]: 1: The accuracy of the measurement itself 2: The assumptions in the calculation that should indicate the body fat percentage with these measurements. So, how the data is collected and how this data is then converted into a number that represents your body fat percentage.

Measuring Body Fat Percentage with Skinfold Calipers

With skinfold measurements, you determine your body fat percentage in the most accurate way. How does this type of measurement work? First of all, you need a skinfold caliper. With this skinfold caliper, you can measure the thickness of the skinfold at various locations on the body. These locations are used as an estimate for the total fat mass of the entire body. So, the thickness of your skinfold at various places on your body determines your body fat percentage. If you want to systematically work on your goals and make progress, measuring your body fat percentage is an essential part. Based on your body fat percentage, you can calculate your lean muscle mass. If you know these data about yourself, you will know if the workouts and nutrition you are currently doing are actually having the expected effects on your body. A skinfold measurement is the best method to measure the development of body fat percentage across different parts of the body. You measure the thickness of the skin at various points. If consistently performed, these measurements show little deviation from measurement to measurement. The accuracy of the measurement itself is therefore quite high [2]. However, these measurements must then be converted into a nice number that represents your body fat percentage, and that is where things can go wrong. There are different calculations based on different target groups (young/old, overweight/not overweight) [3 to 7]. As long as the correct calculation is applied to the right target group, these seem suitable. However, in practice, the same calculation is often applied to everyone. Furthermore, the amount of body fat can influence the accuracy of these calculations [7,8].

Measuring Points with Skinfold Calipers

Body fat percentage can be measured in various ways, with the most well-known method being skinfold measurements. It is a measurement to determine how the body composition in terms of lean muscle mass is and how the ratio with fat mass is. Essential for bulking and cutting. Body weight and Body Mass Index, or BMI, do not provide insight into this. There are various skinfold calipers available, where the goal is to measure skinfolds at various places on the body and add up the millimeters. There is the four-point skinfold measurement and the seven-point skinfold measurement. With the four-point skinfold measurement by Durnin and Womersley, the skinfold measurement is performed in the middle of the biceps and in the middle of the triceps, under the shoulder blade, or the subscapular fold and on your side, the supra-iliac fold. While with the seven-point skinfold measurement, the skinfolds of the chest, abdomen, and thighs are also measured. You then look up the total in the skinfold measurement table, which roughly indicates your body fat percentage. As mentioned, with a skinfold measurement, the thickness of the skinfold at various places on the human body is considered. These places are:

• Biceps – the front middle of the upper arm
• Triceps – the back middle of the upper arm
• Subscapular fold – below the shoulder blade
• Supra-iliac fold – just above the thigh

Reliability of Skinfold Measurements

Measuring body fat percentage with a skinfold caliper remains the most reliable form of body fat percentage measurement. In recent years, many other meters have come on the market that determine body fat percentage based on the resistance in your body. Of course, this can help determine your starting point, but in practice, we see varying results with these impedance meters. For example, the amount of water you drink during a workout can be decisive for the result. Therefore, we always recommend measuring body fat percentage with a skinfold caliper.

Average Body Fat Percentage

Every human needs fat to survive. In general, women have a higher body fat percentage than men. What are the guidelines when measuring your body fat percentage? See the table below for that.

Description	Women	Men
Essential body fat percentage	10–13%	2–5%
Athletes	14–20%	6–13%
Fitness	21–24%	14–17%
Average	25–31%	18–24%
Obese	32%+	25%+

Bioelectric impedance analysis

In addition to skinfold measurements, you can also use bioimpedance measurement, also called bioelectrical impedance analysis (BIA). This is done by standing on a scale where the hands and feet make contact with the electrodes. The scale then sends a small electric charge through your body. Tissues with a lot of water, such as blood and fat-free muscle mass, conduct this electric charge very well, while fat mass does not conduct well. The higher the fat-free muscle mass, the greater the conductivity of your body. Conversely, the higher the fat mass, the lower the conductivity. This is a good way to measure your body fat percentage, but the electric charge sent through your body can vary greatly based on many variables, such as the amount of fluid in your body at that time. Therefore, skinfold measurement is often chosen over bioimpedance measurement. This simple but certainly not the most accurate method is the bioelectric impedance analysis (BIA) and is known from, among others, Tanita scales. Simple: you step on it, enter your weight (and that of clothing) and height. Then all your data is neatly printed on a piece of paper. However, this method has several pitfalls. Simply put, an electrical impulse is sent from electrode to electrode via the shortest path. Based on the resistance it encounters, your body fat percentage is calculated. With the Tanita scales, this is from one foot, along one leg, your pelvis, and back via the other leg to the other electrode under your other foot. So, your waist and upper body are not included. The scale makes assumptions based on the measurement in your legs. Not useful if most of the fat is, for example, in the abdominal region or not [9]. Other methods include from foot to hand. Better but still very error-prone. BIA makes assumptions based on your fluid balance. Muscles contain more fluid than fat mass and therefore offer less resistance to the electric impulse. A varying fluid balance can therefore strongly influence the outcome. The fluid balance can vary greatly from moment to moment and from person to person. To take this into account, you enter your height, but this only partially limits the susceptibility to errors.

DEXA Scan

There are other methods that are more accurate, but are difficult and/or expensive in practice. Especially if you want to perform these weekly to measure progress. One of them is Dual energy x-ray absorptiometry, abbreviated DEXA. A DEXA measurement is actually intended to measure bone density. X-rays are used to measure the density of bones and therefore must also be able to measure the density of surrounding tissue such as fat and lean mass [10,11]. DEXA can also show deviations based on characteristics of the individual such as age, body fat percentage, and in some cases disease [12]. Bone density is accurately displayed but the measurements of the tissue around it can still show deviations. So it is not a “gold standard” although this is claimed by many providers. Because there is no method to compare the accuracy with. At most, you can speak of the most accurate method. A DEXA scan has various disadvantages. One of them is the price. Depending on where you have this done, it can cost around 50 euros. Quite expensive if you want to have a measurement performed weekly. Another disadvantage is that you have to lie still for 20 minutes. “`html See the table below for that.

Description	Women	Men
Essential body fat percentage	10–13%	2–5%
Athletes	14–20%	6–13%
Fitness	21–24%	14–17%
Average	25–31%	18–24%
Obese	32%+	25%+

Bioelectric impedance analysis

In addition to skinfold measurements, you can also use bioimpedance measurement, also called bioelectrical impedance analysis (BIA). This is done by standing on a scale where the hands and feet make contact with the electrodes. The scale then sends a small electric charge through your body. Tissues with a lot of water, such as blood and fat-free muscle mass, conduct this electric charge very well, while fat mass does not conduct well. The higher the fat-free muscle mass, the greater the conductivity of your body. Conversely, the higher the fat mass, the lower the conductivity. This is a good way to measure your body fat percentage, but the electric charge sent through your body can vary greatly based on many variables, such as the amount of fluid in your body at that time. Therefore, skinfold measurement is often chosen over bioimpedance measurement. This simple but certainly not the most accurate method is the bioelectric impedance analysis (BIA) and is known from, among others, Tanita scales. Simple: you step on it, enter your weight (and that of clothing) and height. Then all your data is neatly printed on a piece of paper. However, this method has several pitfalls. Simply put, an electrical impulse is sent from electrode to electrode via the shortest path. Based on the resistance it encounters, your body fat percentage is calculated. With the Tanita scales, this is from one foot, along one leg, your pelvis, and back via the other leg to the other electrode under your other foot. So, your waist and upper body are not included. The scale makes assumptions based on the measurement in your legs. Not useful if most of the fat is, for example, in the abdominal region or not [9]. Other methods include from foot to hand. Better but still very error-prone. BIA makes assumptions based on your fluid balance. Muscles contain more fluid than fat mass and therefore offer less resistance to the electric impulse. A varying fluid balance can therefore strongly influence the outcome. The fluid balance can vary greatly from moment to moment and from person to person. To take this into account, you enter your height, but this only partially limits the susceptibility to errors.

DEXA Scan

There are other methods that are more accurate, but are difficult and/or expensive in practice. Especially if you want to perform these weekly to measure progress. One of them is Dual energy x-ray absorptiometry, abbreviated DEXA. A DEXA measurement is actually intended to measure bone density. X-rays are used to measure the density of bones and therefore must also be able to measure the density of surrounding tissue such as fat and lean mass [10,11]. DEXA can also show deviations based on characteristics of the individual such as age, body fat percentage, and in some cases disease [12]. Bone density is accurately displayed but the measurements of the tissue around it can still show deviations. So it is not a “gold standard” although this is claimed by many providers. Because there is no method to compare the accuracy with. At most, you can speak of the most accurate method. A DEXA scan has various disadvantages. One of them is the price. Depending on where you have this done, it can cost around 50 euros. Quite expensive if you want to have a measurement performed weekly. Another disadvantage is that you have to lie still for 20 minutes.

Bioelectric impedance analysis

Then we have Hydrostatic weighing. To understand how it works, we have to go back to Archimedes. Archimedes discovered that an object submerged in water becomes just as much lighter as the amount of water displaced by it. Based on this, you can determine the density of that object (Density = mass ÷ volume). Because the difference between the density of lean mass and fat mass is known, the body fat percentage can be deduced. Hydrostatic weighing is fairly accurate but does not take into account the fact that the difference in fat-free mass and fat mass varies based on factors such as age and gender. Also, one must account for air in the lungs, so you must exhale all the air. Not pleasant when you are then submerged in water. Anyway, I wouldn’t fancy being dunked weekly to keep track of my body fat percentage. Moreover, the costs are relatively high, and the method is not available everywhere. What’s easier than hydrostatic weighing is the bod pod, or Air Displacement Plethysmography. This method works similarly to water displacement, but now the volume is calculated based on air displacement.

3D Bodyscan

A few years ago, we saw at the FIBO in Cologne a 3D body scanner that used the camera of the XBox Kinect. 3D body scanners are becoming more popular. They use various types of cameras and technology to map the body. Many of these scanners can also estimate body fat percentage. There is therefore little to say about the accuracy of the body fat percentage as they estimate it. The way they do this varies by type, both in terms of calculation and method of measuring body circumferences. I would therefore use the 3D bodyscan alongside another method of measuring body fat percentage and not for the fat measurement itself. Just like skinfold measurement, it can provide insight into the different parts of the body, but in an easier and more visual way. So, a nice evaluation tool.

Best method for you

In practice, it’s best to ask yourself which method is best for you. Why do you actually want to know your body fat percentage? To calculate your nutritional needs? Then consider that with your body fat percentage, a calculation is made that is only a best estimate of your needs. The perfect body fat measurement therefore does not lead to perfect nutritional advice. If it’s mainly about tracking progress, then the number itself isn’t very interesting. It’s more about how this number develops over time. Choose an easy method and perform the measurement under the same conditions as much as possible. Because what matters then is not so much that your measurement indicates 14% instead of 16%. What’s important is that this deviation is constant so that you know you’re doing well when your measurement indicates 12% a week later.