How to Calculate Body Fat Percentage
Posted by Brad Campbell
14
Jan, 2010
An Advanced Fat Loss Post About Measuring Body Composition…by Brad Campbell
Hi lean body lovers…hope everyone’s chillin’ like a villain. Me? I’m livin’ like Thanksgiving. Okay, now that I’m all out of clever intro lines, let’s talk about how to calculate body fat percentage. I’ve been getting a lot of questions on this the past two weeks and I promised several readers that I’d do an in-depth post on the subject.
As you learned in my body composition post, using strictly body weight to measure your fat loss and/or muscle building results is lame and could actually do more harm than good. However, using body weight combined with body composition analysis and girth measurements, will give you a very clear picture of how your physique is progressing from week to week.
Therefore, to really track your body transformation well, you’ll need several things:
—> A scale for measuring your body weight (no more than once weekly PLEASE)
—> A tailor tape measure for tracking girth measurements (I recommend taking these once monthly)
—> SOME WAY of calculating body fat percentage, which we will use to calculate fat mass and lean body mass (these are referred to as body composition measurements)
* The first two items everyone should already have, but the third item is where everyone gets stuck and for good reason. This brings us to today’s topic – how to calculate body fat percentage.
What is body fat percentage? Body fat percentage is the weight of your body FAT divided by your total body weight. Makes sense, right? Body fat percentage is so important because it’s really the only way we can assess your health/fitness level on an individual basis, without regard to your height and weight. We also need to know your body fat percentage before we can calculate fat mass and lean body mass.
Here’s where the problem arises…most people have no clue how to calculate body fat percentage, nor do they know what tools they would need or how to use those tools if they did have them. So let’s take a look at some of the most popular ways to calculate body fat percentage…I’ll arrange these in order of most practical to not-so-practical.
Common Methods Used to Calculate Body Fat Percentage:
—> Bioelectrical Impedance Analysis (BIA) – In my opinion this is the most practical, convenient and consistent way of calculating body fat percentage. BIA uses two conductors that send an electrical current through your body (no, it does NOT hurt and you don’t feel anything, I promise).
Because your fat tissue, muscle tissue and skeletal tissue all have different resistance levels to electricity, the BIA device can determine what percentage of your total body weight is strictly fat.
One downside is that because water is very conductive, your hydration state will have an impact on the body fat percentage that is calculated. In other words, if you drank lots of water before taking a body fat measurement, you could get an inaccurate reading. Same thing goes if you’re dehydrated or even if you just got out of the shower.
There’s an easy way around this problem, though. Just make sure to use your BIA device under the exact same conditions (especially in regards to hydration state) every single time. I suggest using this BIA method to calculate your body fat percentage once weekly, on the morning of your cheat day, BEFORE eating, showering or drinking anything and AFTER going to the bathroom.
As long as you use this method under consistent conditions, I’ve found it to be very accurate and extremely consistent. Okay, so you probably want to know where you can get your hands on your own BIA device and how much one of these babies is going to set you back. I’ve got good news…
There are lots of different types of BIA devices, the most common of which are scales (included in a body weight scale) and hand-held devices. I recommend getting a hand-held device, as my experience has shown them to be WAY more accurate.
I ordered an Omron HBF-306CN online for like $30 and it works great.
This is what I use to measure my own body fat percentage and it’s what I used to measure my in-person personal training and boot camp clients. Never had any issues or inaccurate readings, so long as the above conditions were followed strictly.
A hand-held body fat monitor like this is great because it’s inexpensive, you can use it at any time and it requires no technical skills whatsoever.
—> Girth Measurements With Body Fat Calculator – This method of calculating body fat percentage is my second favorite. Basically, you use your tailor tape to take a few measurements and then simply plug those measurements into an online body fat calculator.
The benefits of this method are clear – it’s quick, easy and doesn’t cost a dime. If you want to use this method, just do a Google search for “body fat calculator.”
The downsides to this method are that it’s way too easy to mess up your girth measurements. If you’re not careful about measuring in the exact same spot every single time, this will throw off your body fat percentage results. It’s also pretty easy to pull the tape too tight or allow too much slack, as compared to previous girth measurements.
Plus, almost all of the online body fat calculators I’ve checked out use different variables, different measurements and different equations to determine your overall body fat percentage. Obviously, this leads to the question of which one is the most accurate…and honestly, I don’t have a clue.
So again, it’s a quick and dirty method to determine your body fat percentage, but don’t get super excited or super bummed if the result is more or less than you anticipated…because it might not be all that accurate to begin with (bummer, I know).
—> Skinfold Test Using Calipers – This is probably the most common way of determining body fat percentage, but it’s a pain in the butt and still has lots of room for error (inaccurate body fat percentage results)…so it’s basically last on my list of “doable” methods.
Basically, this tong-looking tool (referred to as caliper) is used to precisely measure subcutaneous fat thickness at multiple points throughout your body. These measurements are then used to estimate a body fat percentage, after being plugged into an equation. The upside to using a skinfold test with calipers is that when done correctly, this can be extremely accurate.
The downsides are that most trainers have no freakin’ clue what they’re doing when using calipers…and even if you did find someone with superb caliper technique, you’d have to go to that same person every time you wanted your body fat retested, which is very inconvenient and unlikely to happen.
On top of that, different equations require a different number and location of skinfold measurements, which can lead to inconsistencies if you repeat the test in the future with a new equation. Lastly, skinfold measurements don’t take into account other types of fat, such as visceral fat, that is further internal and surrounds your organs.
Calipers can get pricey in a hurry, too. With all of the negatives I pointed out about using calipers to determine body fat percentage, it’s surprising this method is used so often by personal trainers and other health professionals.
An option would be to hit up a local gym trainer and see if they’d give you a caliper skinfold test, but remember that the accuracy of the resulting body fat percentage is dependent on the skill of the operator (which is usually lacking).
The three options just mentioned are really the only practical ways for the average person to calculate their body fat percentage.
—> Other methods include underwater weighing (probably the single most accurate method, but also the most costly and inconvenient), DEXA scan (potentially as accurate as underwater weighing, but still pricey and a pain in the butt to track down and have done) and infrared light (no clue where you’d even get this done or how much it’d cost…I think it’s pretty old school).
There you have it. That’s my story on how to calculate body fat percentage. Any of the first three methods will be your best bet and feel free to try out multiple methods and compare the results if you’d like – this may give you a better idea of which one is the most accurate and/or consistent.
I’ve had real good luck with my hand-held body fat monitor and it’s totally convenient and affordable, which is why using a BIA device would be my top recommendation. Just remember to keep the testing conditions exactly the same, especially with regards to water intake.
If you still have any questions on how to calculate body fat percentage, just hit me up in the comments section below. Hope this helped break it down and you now have a good understanding of the pros and cons associated with each method.
Bottom line is you’ll definitely want to figure out your body fat percentage and track it from week to week, regardless of which method you end up choosing.
Your Coach,
Brad Campbell
PS – The dude abides.
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