Body Fat: The Definitive Guide (Part 2)

Body Fat: The Definitive Guide (Part 2)

In the first part of this series, we talked about the physiology of body fat, its different forms and locations found on the human body. This time, we will learn more about why it’s so necessary to keep our body fat down and how to measure it via the most popular scientific methods. On top of that, we got tips at the end as a bonus!

The benefits of having low body fat levels

Health Benefits

First of all, being aware of anything wrong with your body, makes you accountable of things that might be wrong with your health.

Knowing that you’re above the healthy body fat range, drives you to do something to fix it. The fact that you might not do something right now may not matter, but still it constantly reminds you of the problem. It also makes you proactive. In a sense that if you are just above your accepted percentage, you know that you should pay a little extra attention to it for some time.

The main health benefits though are mentioned already. Excessive fat is linked to type 2 diabetes, insulin resistance and inflammatory diseases.

Your health should be priority number 1. Not your appearance, not your arm size or your booty curves. Period.

Psychological Benefits

We are all familiar with the following scene. A fat kid being bullied by the “jocks” of the school and girls making fun of him.

People can be very judgmental or cruel to other people just because they are above average in terms of weight. Now imagine getting all this psychological pressure while being on a diet, trying to lose fat. Psychology is a huge issue because it can make or break your whole effort of lowering your body fat.

The thing is you have to focus on the positive aspect of it. Think of how many looks you will get when you reach your target looks. Girls especially experience a whole new world when they are more attractive. Suddenly smiles are all over the place, people offering you drinks or even small favors for nothing. Guys get attention too, big shoulders and a small waist go a long way with girls.

Hold on to that, we will get to attraction benefits in a minute.

And if you thought being bullied is bad, there are some even greater pains in life. Many people cannot climb some stairs without taking a break to breath. That hurts a lot. It makes you feel inadequate and unable.

Other people are having difficulties playing with their kids or even having a basketball or a soccer game with them. If you are on the 40+ age range you can totally sympathize with what I am saying. These things could disappear, if you were just a little more fit. It all comes down to body fat once more.

Finally, the feeling of being able to try out all the kinds of clothes you want to go shopping without the feeling of embarrassment is magnificent. I know some ladies can totally relate to that.

What about the beach? Yes, the place where all of the weight resolutions are being set. My favorite sentence is “I will start dieting on Monday”. Every time I hear that, I burst into laughing.

There is nothing stopping you from reaching your goals other than yourself. You can totally reach the feeling of “achievement”, not by being indifferent about your weight, but by being mindful.

Fitness Benefits

I have a basic understanding of freedom, as a state of being able to do whatever you want, anytime you want. When I hear people complaining of not being able to endure a 30-minute run, I automatically feel that they are not free. It should be your choice and not your inability that directs your actions.

Everyone should feel free to run

An interesting fact is that even small increases in body fat can totally affect your performance. Take a racing horse as an example, it typically weighs more than 1000 pounds (450 kg) and has around 5% body fat. Did you know that even 5lbs (2kg) can make it lose a race? That’s only 0.5% of its total weight. I think you get my point.

Now let’s get back to attractiveness.

Attractiveness Benefits

There is a term used in social psychology that is called Reproductive Value (R-Value or RV). It describes the level of attractiveness or beauty of a person. We are constantly evaluating people around us based on their beauty. Not to mention we can even assign nonexistent personality traits just because they are pretty. Look up “Halo Effect” for more info.

So can you guess what’s a very important factor for the R-Value of a person?

Exactly, BODY FAT.

There is even a very scientific and rather deterministic metric regarding attractiveness. You probably have heard the term “aesthetics” and it means having a proportionate body.

The main metric is the waist circumference and more specifically the relation between waist and hips (regarding women) or waist and shoulders (regarding men). Although body fat is not explicitly connected to these circumferences, it relates as you will learn by reading the whole post.

Waist-to-hip Ratio

It is the ratio of the circumference of the waist to the circumference of the hips. It is an indicator of fecundity according to studies and that is its evolutionary reason of attractiveness. The cues that indicate a woman is attractive are directly related to her ability to give birth.

Example: A woman with a 25’’ (63,5cm) waist and 38’’ (95,6cm) hips is having a 0.65 ratio.

Waist-to-shoulder Ratio

It is the same with WHR although instead of hips we measure shoulder circumference.

Example: A man with a 34’’ (86.3 cm) waist and 45’’ (114 cm) shoulders is having a 0.75 ratio.

As we have already mentioned, girls tend to store fat on the lower section of the body while guys mostly on the belly.

Therefore, the ideal woman should have a slightly bigger hips size compared to her waist and the ideal man should have a relatively smaller waist compared to his shoulders, the Adonis Index. Remember the V-shape for men and the “hourglass” figure for women.

In case you are a nerd like me and you have a thing for numbers, there is an “ideal” number for those ratios. Its 0.618 or 1.618.

The ideal VShape

Get your measure tape out.

I hope you didn’t get bored with all the benefits of a better body.

How about we dive into some more practical stuff regarding body fat?

Measuring your body fat

There are many ways that we can measure our body fat. We are going to learn about the most popular of them.

Bioelectrical Impedance Analysis (BIA)

This method is based on the premise that fat-free tissue is a good conductor of electrical currents while the fatty tissue is a bad one. So the impedance to current flow is inversely related to the fat-free mass and body water.
In simple words, the more fat you have the less electrical current can push through your body.
The way it works is very simple. A small, harmless, electrical current passes through your body and measures the resistance. Then your weight, height, age and sex are taken into consideration and an approximation of your body fat percentage is calculated.
There is a protocol that must be followed in order to have more accurate results.

  • No exercise or sauna within 8 hours of the measurement
  • No alcohol 12 hours  prior to the exam
  • Use the bathroom, to get rid of any water
  • Try to avoid drinking much water prior to the measurement

Generally I don’t consider BIA a valid measurement for body fat, but it is a good indicator for tracking changes in your body fat. Try to think of it as a reference point and check your progress.

Underwater or hydrostatic weighing

The procedure is based on Archimedes’ principle.

“The buoyant force which water exerts on an immersed object is equal to the weight of water that the object displaces.”

The method is very simple. We calculate the density of the body based on the volume of water our body displaces and then we can calculate the body fat according to the equations by Siri and Brozek.

Siri (1956): Fat % = [4.950 /Density – 4.500]×100
Brozek et al. (1963): Fat % = [4.570 /Density – 4.142]×100

It has been considered for many years the definitive procedure for measuring body fat. It is a little bit unpractical as you have to immerse yourself in a water tank, but it is rather accurate.

Air displacement plethysmography (ADP)

You may have come across it as the “BOD POD” which is one of the models for air displacement measurement. It is a scientifically validated densitometric method. It is kinda the same with hydrostatic weighing, with the obvious difference that your density is measured against air displacement rather than water immersion.

You have to wear a tight swimsuit and a swim cap, sit inside the machine while breathing for several minutes and mainly that’s it.

Dexa Scan (Dual energy x-ray absorptiometry)

This method measures your body fat by first evaluating bone mineral density, lean mass and fat mass. Two x-ray beams of different energy levels are being sent through your body (while on a horizontal scan). Then you can determine the density of your body’s bones or soft tissue by the absorption of each beam.

Dexa scan is relatively safe, as it uses a much lower level radiation than the standard X-Ray examinations.

Skinfold Measurement

This method was introduced by Dr. Andrew Jackson and M. L. Pollock in 1978. They made a research and came to the conclusion that, since subcutaneous fat is the majority of body fat, it can be used to calculate your total body fat. Obviously this method cannot take into consideration the visceral fat.

This should preferably be done by a professional. This is for two reasons. The first one is that a professional is experienced in doing that and the second one is that you need always to be consistent in the way you are being measured. In case you want to try out for yourself, you can follow this guide of Skin-Fold Measurements where you can also find information about the equations used.

Circumference Measurements


This one is the easiest method, you don’t need any professionals and you can totally do it yourself in no time. The concept is that your body fat can be estimated (± 2.5%) by the circumference of 3 places on your body and your height. These places are different for men (neck, abdominal and hip) and women (neck, waist and hip). The formula was introduced by Hodgdon and Beckett in 1984 and was developed in the NAVAL HEALTH RESEARCH CENTER. A good calculator you can use and see the equations is this

So that was it about the body fat measurement methods.

If you need my opinion on that, it is very simple.

  1. Beginners or people with a serious fat problem:
    Circumference Measurements. Fast, easy and reliable for tracking your progress
  2. Athletes and enthusiasts of body recomposition:
    DEXA scans, most accessible method compared to water weighing and air displacement. Also, lets you know about the health(density) of your bones as well.

So how do we lower our body fat?

Ok, I am not gonna elaborate on that one, we may need at least a post to even start on the basics of fat loss. Although the obvious two things, that always need improvement, are nutrition and training.

So here are a few quick tips and at some point we will tackle this issue more thoroughly.


Psychology is probably the most decisive factor on following a diet plan. If you get your mind around it, you can achieve whatever you want. Trust me on that one.

A great read about that is called “A Guide to Flexible Dieting” by Lyle McDonald. He has mentioned that it’s his less popular book. According to me, it’s extremely useful and it gave me one simple tip that turned my whole approach upside down regarding sticking to a diet. Ready for it?

DIET BRAKES  or Maintenance Diet (on schedule)

Suggestion of the book:

  • 6-8 Weeks ON
  • 1-2 Weeks OFF (free, maintenance diet)

The concept, he is describing, is far from just that, so I strongly recommend reading his book “A guide to flexible dieting”.  It has a lot of options regarding your level in training or body fat.

He is a genius and he has written a lot of great books.



Strength training can do wonders for fat loss, as long as you don’t so silly things and hurt yourself. The way to do strength training is by practicing the Big Five exercises. Bench Presses, Barbell Rows, Deadlifts, Overhead presses and the elusive Squat. You should always overload progressively. Meaning start with a relatively big set, like 12-15 repetitions and then make your way to 4 or 5 repetitions. Again this is just a proposition for strength training, as you get more experienced, you will need to adjust accordingly.

Lower intensity works as well, as long as you take the time to reach the calories burned needed. I strongly recommend getting a heart rate monitor, for both strength training and lower intensity cardio. You get a good idea of how your heart works during these activities and you get a good idea of calories burned. If you find that your heart is starting to beat on a lower frequency during exercise, probably that’s good, you are getting fitter. But it also means you have to up the intensity a bit.

Personally I like to do both. Mainly strength training but every once in a while, when I feel tired or not in the mood to lift the whole world, I would do a cardio session of 1 hour at 130-150 bpm (approx. 650-700 cal).

Conclusion and takeaways

  • Make a habit of measuring your body fat. At least annually. Preferably, along with blood work.
    Very Important, try to always measure yourself under the same conditions every time. Even if your measurement is wrong, you still have the same factors affecting all measurements, so you know your progress.
  • A high percentage of body fat is associated with increased risk of serious health issues like hypertension, type 2 diabetes, depression, heart diseases, respiratory problems or even some cancers. You can minimize those risks by lowering your body fat.
  • You deserve to be free, try out all the clothes you want and feel attractive all the time. Do something for it!
  • DEXA scans can be very accurate, nonintrusive and accessible.
  • Girth circumference measurement is the easiest method to track your body fat percentage.
  • Make training and dieting a part of your lifestyle