# Method in the Fatness



## AChappell (Jun 1, 2011)

*Method in the Fatness*

BSc (Hons), MSc Andrew Chappell

*Body Composition Analysis*

As bodybuilders, fitness enthusiasts, coaches and athletes we can become obsessed with facts and figures, counting everything from calories, and reps, some might even go so far as record the ketones in their urine. Weighing standards or something like biosigniture are twotools were a coach or athlete can rightly or wrongly become obsessed with things like height for weight or body composition. However such methods should always be taken with a pinch of salt, since performance doesn't always correlate with body composition. Runners or swimmers for example may wish to have a slightly higher bodyfat percentage (BF%) than that of a Olympic weight lifter or sprinter, is it sensible for them to remain at 5, 10, or 15% for the sake of training, while anomalies even in elite sport are often present.

So how much weight should we give to the idea that optimal performance can only be achieved at certain BF% levels? It doesn't take long browsing fitness forum or facebook, before you see people proudly boasting precise levels like 3.6% or shamefully admitting to levels of around 29%. In fact whole training programs and dietary guides are based on obtaining ludicrously low levels or maintaining a BF% for "optimal anabolic hormone balance". People can become obsessed, fearing deviation could result in injury or potentially diminishing returns. The single take home message from this article should be, how do these people actually know what their body fat actually is? And can you accurately measure body fat? The short answer is no, not really. What follows is a short summary of the two trips I made to the Human Nutrition Unit (HNU) Aberdeen to have my BF% measured by three different methods (air plethysmorgraphy, skin fold thickness and bioelectrical impedance) which I hope will Illustrate this point perfectly.

It's important to understand that any assessment of body composition, is essentially based on a two component model, unless a MRI is used. The body is broken down into two parts: fat mass (FM) and fat free mass (FFM), and that the equations used to assess BF% are based on the assumption that FFM density is the same between individuals and tissues. When you consider that the two compartment model assumes muscle, organs, and bone to be of similar density between individuals, already you should be questioning the accuracy of any BF% results. Air plethysmorgraphy like densitometry (underwater weighing) is based on this principle. Where density can be calculated by the mass (weight on the scale) divided by the volume (displacement of air or water). However it's almost impossible to account for things like GI tract volume and lung volume has to be taken into consideration, pressure and temperature can also affect the end results, as will the calculations used to correct for these factors.

Other issues become apparent when you consider that the Siri equations (1961) used to convert body density into a BF% were originally designed based on a non-athletic population. The story goes that they were in fact based on the weighing and measurements of cadavers. The Durnin and Wormesley skinfold calculations perhaps the most widely used formula for estimating BF% suffers from a similar problem. Errors can be confounded when comparing athletic with non-athletic individuals, or by a practitioners skill in when taking skinfolds. In fact if you even want to take skin folds for UK athletics for example ISAK accreditation is essential. Can you really trust a gym instructor with a cheap set of callipers to be reliable and accurate when comparing someone with a level 4 ISAK. Taking such measurements requires considerable practice and a methodology unfamiliar to most. Following your skinfolds UK athletics might not even bother with any equations and just use skinfold thickness instead to measure progress. A method like bioelectrical impedance makes similar assumptions to the previous two methods mentioned. It's based on the two compartment model, and a non-athletic population, although correction equations can also be used with varying degrees of accuracy that may or may not correlate with densitometry. Impedance is based on conductivity of a current through the body, where greater FM will impede the current. However simple things like your electrolyte and water intake can often alter the outcome and the method is often not regarded as reliable.

Anyway Here are the results of my BF% tests the 1st visit was performed 3 weeks out from the BNBF British finals the 2nd was 6 days out.



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The difference between the results are striking, with almost a 7% difference between the skin folds and bioelectrical impedance, and based on the limitations of each method who's to say skin folds are any less reliable than densitometry. Only a MRI would perhaps give you a more accurate estimate of BF% since something like DEXA is still based on similar principles. So is there method in the fatness, like I said no, not really and since it's difficult to really obtain accurate results, is BF% really something we should be concerning ourselves with?


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## JGSPT1989 (Jan 7, 2012)

Great article, the differences are astonishing, i suppose even though you will never get a really accurate bf% reading if you uses the same method of measuring it as long as its coming down your happy lol although as you have said certain things can change the results.


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## justheretosnoop (Jun 15, 2012)

Great article Andy.

To answer your final Q, is BF% something we should be concerning ourselves with? My answer would be a mixture of yes and no. No in that the exact level of BF itself doesn't really matter so long as you're in the condition you want to be in (for both competitors and general gym-goers) - you yourself know exactly how you need to look coming in for a show so i'm sure a BF reading of any sort wouldn't make too much difference. BUT...I do find regular readings using the same method a good tool in the arsenal to monitor ongoing progress. I couldn't particularly care what the reading may be at any given time, it's just used as a comparison to those from previous months so I can potentially review my diet/training accordingly. I would never rely on it alone though given the variables, it's just another piece to the jigsaw so to speak. Plus, if it's something I can bang in a spreadsheet then i'm game!!!!


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## Loz1466868022 (Oct 12, 2011)

I only rely on my sight as far as my own BF is concered, i can judge my body and the changes as i look at it with a critical eye on a daily basis and looking at the results over a period of time/photos, i am however amazed at the % diffrence, what would you say Andy is the most accurate in your opinion knowing your body better than others?


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## AChappell (Jun 1, 2011)

Photo's in a the same light at the same location maybe just as good Loz, I think you've got the approach sorted. Most accurate in my opinion, I honestly couldn't say. my bf% is probably somewhere between the bodpod density method and the skin fold. This is my point though Loz unless you get a MRI you hav no idea what your BF% is it's simply guess work.


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## Loz1466868022 (Oct 12, 2011)

AChappell said:


> Photo's in a the same light at the same location maybe just as good Loz, I think you've got the approach sorted.


OOOhh lol i promise week 12s will be, no MRI soon then dont they cost a bomb? oh well guess work it is


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## roadrunner11466868009 (Mar 28, 2011)

I use calipers as a guide only it gives me some encouragement if the reading is reducing on a regular basis. That said for me the real test is the tape measure and the mirror.


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## AChappell (Jun 1, 2011)

Your standard MRI is around about £1000 a shot, you might get mates rates at around £800, while something like a DEXA can be about £400 a time. So measuring BF% accurately isn't cheap.

All you can do is simply use something like skin calipers as a guide. The tape measure is also a great way to track your progress and if your trying to lose weight, then something like the waist to hip ratio can also be useful.


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## EXTREME (Aug 5, 2005)

You can tell when your body fat levels are at an acceptable level when you are happy with how you look and feel confident.

Numbers mean nothing in my mind, it's how you feel within yourself as a person.


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## ElleMac (Sep 20, 2011)

I use the "jump and wobble" test- if I jump and it wobbles then it's fat!

I used a measuring tape and in 6 months (this was before I dieted for a competition too)- my waist went from 33" to 25" (It's still 25" off season) and my hips from 42" to 35". That's soooo satisfying, as with women, 2" is a clothes size!!

Sent from my HTC Desire S using Tapatalk 2


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## gingernut (Dec 11, 2006)

About 15 years ago I had what I consider my only accurate BF analysis,this was taking part in some sports science research looking into ammenorhea(sp?) in good level athletes. I was given a bone scan, then the same machine did a bodyfat scan. I was strapped down onto a table and some sort of lazer or scanner passed over every part of my body.Would this be a dexa?

The results I got gave me BF levels in each limb plus torso. It said I had an overall BF % of 21 which was mid range for the subject group they were testing.

Since then I have used Bio-impedance scales but once I get below what I believe to be 16 or 17% they no longer respond even on athlete setting. I rely on how I look most of the time, BF scales when I'm really out of shape and seems to work for me as a guide to how I'm doing.


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## AChappell (Jun 1, 2011)

lancashirerose said:


> About 15 years ago I had what I consider my only accurate BF analysis,this was taking part in some sports science research looking into ammenorhea(sp?) in good level athletes. I was given a bone scan, then the same machine did a bodyfat scan. I was strapped down onto a table and some sort of lazer or scanner passed over every part of my body.Would this be a dexa?
> 
> The results I got gave me BF levels in each limb plus torso. It said I had an overall BF % of 21 which was mid range for the subject group they were testing.
> 
> Since then I have used Bio-impedance scales but once I get below what I believe to be 16 or 17% they no longer respond even on athlete setting. I rely on how I look most of the time, BF scales when I'm really out of shape and seems to work for me as a guide to how I'm doing.


That machine your referring to Rose is a DEXA. I'd give up on the Bio-Imp post some pictures here and we'll tell you if your holding too much fat!


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## Plod (Nov 11, 2013)

Interesting reading

Jan '12 I was 26st 10lb, and then undertook a lifestyle change.

At present, I am 18st 5lb, but have plateaued in my weight loss. Whilst i'm not unduly bothered about this, as I believe my working out 6 days a week, must be reducing my BF and increasing muscle mass.

I was leaning towards somehow trying to measure BF to assess whether my above belief is indeed correct and i'm aiming in the right direction.

Since reading your post, I feel a bit more educated, and in my current form, i'll stick with the mirror and the tape measure.

I'm not in a position where knowing is that critical, it just would of been a nice indication.

I'm a long way from being where I need to be, so will keep plugging away, and as said, feel a bit more enlightened thanks to this thread


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## AChappell (Jun 1, 2011)

I'm glad you found the post useful, keep up the good work you've made fantastic progress just keep "plodding" away!


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## ronnie cutler (Dec 29, 2009)

I believe that I am somewhere in the range of 15-18% BF

but I had a skinfold test at my gym this week that resulted in a measurement of 11.57%!! Haha

I just laughed


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## AChappell (Jun 1, 2011)

Probably down an issue with the person taking the skin folds Ronnie, Skin Folds should be done a minimum of twice or 3 times if their out. Few personal trainers or instructors however are actually qualified to take such measurements correctly. yet more creedance to my original post. good numbers by the way, time to squat more though!


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## ronnie cutler (Dec 29, 2009)

hmm ... she did take 3 lots of measurements but how accurately I couldn't say

I'm not sure what benefit it is to know your BF though I suppose ... there's no contest specifically for the lowest BF!!


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## robinjohn12 (Feb 28, 2013)

great work done by you, because of this info lots of people get information related fatness.


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## AChappell (Jun 1, 2011)

What do you mean by information related fatness robin john?


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## daddy123 (Nov 30, 2012)

I use the calipers more as a guide to see if i am losing, but photo,s and the mirror can give you a better overall way of assessing your progress.


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## Piranha Smudge (Jan 16, 2011)

Extreme said:


> You can tell when your body fat levels are at an acceptable level when you are happy with how you look and feel confident.
> 
> Numbers mean nothing in my mind, it's how you feel within yourself as a person.


Ur not wrong Doug!!! Mirrors my friend!!


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