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Body Fat Measuring Shootout: Calipers vs BIA vs DXA Scan

 

Body Fat, our nemesis. The bane of our existence.

 

As physique sculptors, body fat is something we all would like less of. It hides the beautiful granite, striations lurking below the skin. It’s the reason we choose to eat better. It’s the reason we exercise, sweat and keep active.

When we look in the mirror, we have an idea of when we are storing more or less fat, but we don’t really know where we’re at percentage wise.

You can snoop around on the net and find general pics and guidelines as to what certain body fat percentages look like, but they don’t accurately tell us what our body fat percentage is. We are left pretty much guessing. The good news is, we don’t have to.

 

We have the technology.

 

The most common ways to measure your body fat are:

 

          1) Body Fat Calipers – A hand held tool and the cheapest method to measure body fat. The good news is, you can do it at home though it has the reputation of being the least accurate method. We will soon find out.

 

          2) Bioelectrical Impedance Technology (BIA) – Two electrodes are used to send a low current through your body. The resulting resistance is then converted into a body fat percentage. It’s based on the principle that lean mass has a higher water content therefore a lower resistance than fat and bone. These can also be bought for home use and are usually in the form of a weigh scale, but are more expensive than the caliper route.

 

          3) DEXA Body Composition Scan – Low dose X-ray is used to determine lean mass, fat mass and bone density. It’s a medical grade test used on professional and olympic athletes and is the Gold Standard for body composition. This is the most expensive option, and would not be very economical to purchase one for home, unless you’ve got more money than you know what to do with.

 

I had a DEXA scan body fat percentage done and the result was 9.9% body fat.

 

 

This will be the standard to which we will compare the accuracy of the other two methods.

For accuracy purposes, all tests were done on the same day.

Let’s get to it!

 

First up…

 

Body Fat Calipers

The two types I used were:

1) Defender – It uses a mechanical pressure indicator that turns green when you have the correct fat pinch pressure.

I read the manual and measured each of the three spots (upper side pec, beside belly button, upper thigh) 3 times and came up with an average of 22, which corresponds to 7.8% body fat on the wheel chart that is included with the calipers.

Over 2% lower body fat than on the DEXA! Not very good, unless you enjoy bragging to the birds about how ripped the calipers said you are hahaha.

I tried a couple more times just to see if I was making any mistakes with the amount of pressure I was applying and skewing the result. NOPE. 7.8% was the highest BF percentage I got from the Defender. The lowest I got was 6.8%. So the readings varied by up to -1%. Not so good

 

2)  Fat Track II – This one has a digital read out and beeps when you have applied enough pressure for the fat pinch. I entered my simple profile (gender, age) into the unit, then it prompts you to go through the 3 pinch spots, then automatically calculates your body fat percentage.

Out of the 5 times I tried it, the lowest body fat it spit out was 5.8% and the highest I could get, trying hard to get closer to my ACTUAL body fat percentage was 8.0%. Not only was the closest I could get to my actual body fat 1.9% less, the range of readings varied a whopping 2.2%. Neither accurate nor repeatable. Not very good at all.

 

Second up to bat…

 

Bioelectrical Impedance Analysis

For this test I used the Tanita TBF-410 at my friendly neighbourhood Goodlife Fitness. The trainer showed me how to used it for the first trial. You must go in with bare feet.

You enter these values:

  • the approximate weight of your clothes
  • gender (and body type standard or athletic)
  • height
  • age

Then you step on the scale.

Here’s what I got:

Only 201.6 lbs for the weight and 11.5% body fat.

 

Take two was not much better:

My weight magically jumped up 1 lb and the body fat got even less accurate at 11.7%. On the bright side, at least the readings for this device were more consistent than the calipers, but the error was still quite high with an overshoot of between 1.6-1.8%. Quite significant.

 

Verdict

 

Neither the calipers nor the BIA device were very accurate when compared to the DEXA scan standard. Both calipers showed significantly lower body fat than than I actually had, and varied wildly in range depending on the placement of the device and pinch technique. The BIA device showed significantly higher body fat than what was measured via the DEXA standard, though the device seemed to be a little more consistent in its erroneous readings.

In my opinion, you can’t rely on accurate measurement with anything but the DEXA scan. There are too many variables that leave room for error in both other methods I tested. I suppose one could use the other methods as a way of gauging fat loss/gain as a general trend up or down, but you can’t accurately determine your true body fat percentage with anything but the DEXA scan out of the methods I have tested.

At some point I’m going to test the water floating method against the DEXA to see how it fares, but that will be at a later date.

Bottom line

If you’re serious about wanting to gauge your fat loss progress accurately, the only sure fire way is to buck up and pay for a little bit of radiation and find out EXACTLY where you are at in your fat loss journey.

 

That’s a wrap.

Happy shredding.

 

Yours Truly

Dreamscore

 

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