Body Fat %: What is it, why is it important and how do I measure it?

Hopefully everyone had a good Memorial Day and a long weekend. And now that everyone has stuffed their face with food and booze, let’s talk about that stubborn fat you cannot wait to get off. I’m nice like that.

In the industry that most of us are in, and with such a focus on ‘being lean’, it is no surprise that everyone is curious as to what their body fat % is. Some of us have an idea about we’re we are and where we want to go; however, there is a gross distortion of what body fat usually is!

I got this question a lot around the gym this weekend (yes I still worked during the holiday weekend, somebody has to do it), “What is this [points to fat] and why is it here?” My response is always the same, “That’s excess body fat.” After that I usually remain quiet because the inner sarcastic person in me always wants to say, “…and that’s because you ate too much and didn’t leave your couch.”

Jokes aside, high body fat % has been a problem here in ‘Merica. I’m sure you’ve all heard from most news and educational sources about how bad the epidemic has become; and you know what, it’s our own fault. However, lately we have laced the f up and begun to change. In today’s post I will briefly describe what body fat is, why it is important and give you some comparable data.

Basic Definitions and Concepts of Body Composition

Body composition refers to the makeup of lean tissue and fat tissue in the body. So:

1. Lean Tissue – Also called free fatty mass (FFM). This is composed of muscle, bone, organs, glycogen, blood volume, water, hair, nerves and a few other bits and pieces. Basically everything but fat.

2. Fat Tissue – Composed of two different categories: essential fat, and storage fat.

a. Essential fat – Required for life and physiological functioning. This is fat stored that is part of nerves, bone marrow, the organs (heart, lungs, liver, spleen, kidneys, and intestines) and also the muscles. There is thought to be ~ 8-12 % in females and ~ 3-5% in males. The reason for the difference is essential fat between the sexes is the job this fat does. The extra ‘fat’ that is essential for females is thought to be due for reproductive requirement for babies, hormones (and no that doesn’t mean you can blame your mood changes on essential fat) and such. It is essential RESERVE fat found in breast tissue and lower body stores. In males, essential fat plays a role is hormone transport and balance but that’s mainly it. *Any decreases past these points can have grave consequences on body function*

b. Storage Fat – Generally divided into – VISCERAL fat (around organs and in the abdomen) and SUBCUTANEOUS fat (under the skin). Females have less subcutaneous fat than males. This type of fat that has created the problem for the past decade. Excess storage fat, obesity, has been linked to a variety of diseases: hypertension, type 2 diabetes, heart disease, sleep apnea…I can keep going. It is also this type of fat that we use as fuel during exercise (in conjunction with carbohydrates) so fear not, we can always decrease this number.

Well Josh….how do we measure this? Well glad you asked, let me show you.

Measuring Body Fat %

There are many, many ways to find out your body fat percentage, and these all vary in accuracy and availability. Generally speaking – the more accurate the method, the more expensive and ‘unobtainable’ it is. Going from MOST accurate to LEAST accurate:

•DEXA Scan – This involves a full body x-ray like that used for bone density scans. This is the most accurate method; however, scan can get costly and only highly specialized places have a DEXA as each one cost around $55K per machine.

•Underwater/ Hydrostatic Weighing– (also called water displacement) An individual is submerged and weighed under water, with all the air blown out of their lungs and a percentage of fat and fat-free weight is calculated from body density. This method plays on Archimedes’ principle (look it up I’m not explaining it). Very accurate method and probably the best to use if available. Only takes a few minutes and results are usually given on the spot.

•The Bod Pod – Similar concept to underwater weight, but the individual is placed into a small chamber and the amount of air displaced is measured by sensors and calculated into a BF %. Also accurate, but not widely available because the concept is fairly new. Also people who can become claustrophobic should stay away from this.

•Skin-fold measurements/ calipers – Folds of skin are measured with a caliper. The measurements are used in equations that link the thickness of skinfolds to percent body fat calculations. It can be done via ‘3 sites’, ‘4 sites’ and ‘7 sites’. It is simple and available, but needs to be done by someone who is trained and there are wide variations in accuracy.

•Bioelectrical Impedance (BIA) – These are scales or hand-held devises that run an electrical current through the body to determine water content. They vary in accuracy according to the specific device (some brands are better than others), the number of attachment points (foot and hand electrodes are more accurate than hand held or scale devises), and the user. Example: if you use a SCALE only – the electrical impulse takes the path of least resistance – so travels up one leg, and straight down the other. Thus, it basically measures LOWER body %. If you use a hand held device, it only measures UPPER body %. Similarly – As they are based on WATER content – fluctuations in hormones/ hydration throw values out. So – the best results are obtained first thing in the morning after emptying bladder/ bowels, with no alcohol consumed for 2 days prior, and no exercise the night before, and – hormone free.

•Tape measure method – There are a number of formula based on several body measurements taken with a tape measure. It can be roughly accurate, but it does depend upon your ability to accurately measure as well as body shape/ type. Although LEAST accurate – it is especially useful for tracking yourself over time as it is readily available.

Body Fat % in Females

Ok ladies, let’s spend some time talking about you. Generally speaking – most athletes range between 12-20%. Most fit females in the general community are 15-22%. As of 2010, the average American female is anywhere from 22-25%. In females, the lowest values for body fat correspond to the essential fat content (about 8-12%). This level of fatness is extremely low (professional bodybuilder on stage). And once a female reaches <12%, especially for prolonged periods, they will run into issues with health (lack of periods, decreased immune function, decreased recovery, decreased bone mass, etc).

Body Fat Categories for Women:

8-12% – Essential Fat

13-20% – Athletic Fat Levels

21-24% – Fitness Fat Levels

25-29% – Acceptable Fat Levels

>30% – Obese

There are many…MANY factors that play into body fat % that I will discuss in later post. For now this is a general overview of what makes up body fat and how to measure it. This Saturday, I’ll talk about exercises that will help you lose that stubborn fat and get that muscle definition you’ve always wanted.



3 responses to “Body Fat %: What is it, why is it important and how do I measure it?

  1. Pingback: MrMary Responds to: Why It’s Okay To Be Fat by Golda Poretsky | ASpoonfulofSuga·

  2. This is spectacular information. I’m generally very happy with my body, but am having great difficulty losing what is probably 3 lbs of lower abdominal fat. Pushups…crunches…eating excess fiber…drinking more water/green tea…nothing I’ve done in the last month has budged it! It looks ridiculous on my otherwise slim stomach, so here’s hoping I’ll learn how to get rid of it here. 🙂

  3. Keep it up! with the correct exercise and diet, you’ll be getting to your goals in no time. if need be, ramp up the intensity in the weight room, incoorperate more circuits and interval training into your program.

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