How Should You Measure Your Percentage of Body Fat?

When it comes to measuring your body fat percentage, the best option is a magnetic resonance scan, although these aren't generally used for this, given their price and availability. So, what other options are there?
How Should You Measure Your Percentage of Body Fat?

Last update: 11 April, 2021

There are various methods available to measure your body fat percentage, although not all of these methods are as reliable as others. Understanding your body’s current composition can be important when it comes to knowing whether you need to make lifestyle changes or not.

The majority of the methods for measuring body fat can actually be slightly inaccurate. These tools can be useful to track changes over time, but you shouldn’t take just one isolated measurement as the whole picture.

Anthropometry: using skin thickness to measure body fat percentage

This is one of the most common methods used around the world to measure the percentage of body fat. Anthropometry is the science of measuring the human body. Here, it involves using skinfold calipers to measure the thickness of your skin.

After you take your measurements, you can put the results into a calculator that has a specific equation. It’ll show you a prediction of your total body fat. This method of calculating your body fat requires a certain amount of experience. Therefore, it’s best to see a certified professional so you can avoid any errors.

In an article published by The Indian Journal of Medical Research, this method is explained in greater detail. Remember that it’s a complex process. You have to take the measurements at specific points on the body, not just anywhere.

Depending on which equation you use for the body fat calculation, you’ll also get slightly different results. That of course makes this method a somewhat inaccurate way of testing body fat. At any rate, this method is useful for measuring the changes in an athlete’s body composition over a long time, for instance.

Bioimpedance to measure body fat

A pair of scales.

Currently, there are various methods available that use mathematical models. They allow you to calculate your body fat percentage. One example of these methods is bioimpedance.

This method is based on applying an electrical pulse to the body using electrodes. The machine will measure the time the pulse takes to travel through the body’s tissues (how much it resists or opposes the current). Since the speed that the current will pass through a fatty or a lean area of the body is different, you can obtain an estimate of the body fat and muscle mass.

A study published in the magazine Meat Science gives further information on the method, including details on its precision. Keep in mind the fact that this isn’t a foolproof method. However, you can use it to determine body composition changes over a period of time, as with the previous method.

Magnetic resonance imaging (MRI)

This is the most reliable method to measure the percentage of body fat, although it’s also the most expensive. In fact, it’s generally not used for this purpose, since it’s more for diagnosing diseases and injuries.

MRI, however, is very effective. It makes a digital map of the body’s tissues, using a strong magnetic field and radiofrequency currents. These stimulate the body’s protons and the machine measures how fast these protons react to the currents, using these speeds to differentiate between different types of tissues. MRI is a very complex technology, but it’s also extremely accurate.

A man about to have an MRI.

MRI is viewed as the ‘gold standard’ for accurately measuring body fat. However, remember that it’s not used very often for this purpose. Generally, only hospitals have MRI machines, and long waiting lists are common.

It’s possible to measure your body fat percentage

As we’ve seen, the most accessible methods for measuring your body fat are also the most inaccurate, since they’re only providing estimations. To get the most accurate results possible, you should use reliable skinfold calipers and see a professional. The margin for error is large.

However, if you consistently use the same method, it can be very useful to track your progress over time, as well as providing a guide to the efficiency of a diet or a specific physical activity. Professional sports teams tend to use these more accessible methods. Meanwhile, MRI has other more specific uses, such as diagnosing structural injuries.

It’d be ideal to use these methods with the help of a specialist or professional. In that way, you can minimize any errors and enjoy a reasonably accurate result. Of course, the specialist will help you to draw conclusions from the results.

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All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Kuriyan R., Body composition techniqes. Indian J Med Res, 2018. 148 (5): 648-658.
  • Moro AB., Pires CC., Silva LP., Dias AM., et al., Prediction of lamb body composition using in vivo bioimpedance analysis. Meat Sci, 2019. 150: 1-6.

The contents of this publication are written for informational purposes. At no time do they facilitate or replace the diagnoses, treatments, or recommendations of a professional. Consult your trusted specialist if you have any doubts and seek their approval before beginning any procedure.