Measuring body fat %: which is the most accurate method?


Health and Wellbeing / Wednesday, December 19th, 2018

If you’d have asked me a couple of months ago what my body fat percentage was, I wouldn’t have had a clue, or known much about the best way to measure it. Recently though, I’ve been on a fat loss program in preparation for a photoshoot, and to track progress, I’ve been keeping a close eye on my body fat and measuring it every 1-2 weeks.

If you’re interesting in knowing more, my blog ‘Body fat vs. weight’ – explores some reasons why you’d measure your body fat percentage rather than just weigh yourself when tracking fitness progress. But, now we’ve covered the ‘why’, let’s look at the ‘how’.

How do you measure body fat % and what is the best method?

There are loads of ways to measure body fat – all with different levels of accuracy. Since I’ve been monitoring my body fat almost every week, I thought I’d try a few different methods, and compare my results / experiences. Here’s what I found last month from trying out 3 different widely-used methods:

Callipers / Skin folds test

This is the method my coach – James Piper has been using to measure my body fat. True to its name, this method requires you to take measurements of various skin folds in areas around the body (pinching with callipers and separating fat tissue from surrounding tissue to measure the fat). These measurements are then put into a formula to estimate overall fat percentage in the body.

The downside to skin fold testing?

  • It’s pretty awkward being pinched in intimate areas of your body by anyone, never mind someone you don’t know that well.
  • As it’s measured manually – human error always comes into play in these sort of situations so the more trained the tester the better.

What are the benefits of skin fold testing?

  • You can test in different sites on the body so you know where you are losing fat from proportionately rather than as a whole sum.
  • The tools are accessible from most gyms and fitness institutes.
  • Cheap, and regarded as one of the more accurate methods of measurement.

Skin fold testing – yay or nay?

Once you get over the initial violation of someone pulling your fat from your body and pinching it with a cold metal instrument (if you bruise easily like me, that’s an added bonus :D), it’s actually a great way to track changes in body composition and proportion of fat in different areas of the body.

Tips for skin fold testing

  • Make sure you do a 9-site test for a more accurate estimation and representation.
  • Make sure a professional is doing the testing, and that they’re getting the same spot each time for consistency. 
  • Assess the callipers being used. A good set of callipers can retail for around $400 or more – and some PTs might be using cheap ones that aren’t as accurate.
  • Try not to kick the tester in the face if they hurt you while pinching your leg 😀

Here are my results within a 4 week period:

You can see here that the body fat in each site of my body – biceps, chest, abs, thigh, triceps, subscapular (around the back near the shoulder), suprailiac (top of the hip joint), lower back, and calf – has slowly and linearly decreased, showing a reduction of around 2% in that period.

 


Skin folds November 15 result: 19.92% body fat at 56.2kg


DXA / DEXA scan

A DXA or DEXA scan is traditionally used to measure bone loss / bone density and diagnose things like osteoporosis using X-ray technology. They’re now commonly used to measure fat, muscle and bone composition in the body. In my visit, I lay down and was scanned by the technology within minutes before discussing my results with the practitioner.

DEXA scan – what are the benefits?

  • The DEXA scanner is widely regarded as one of the most accurate forms of measuring body fat %. It measures the density of every square cm of your body to determine its composition as opposed to other methods like impedance measurements.
  • It can therefore detect muscle, fat and bone regions that other methods can’t, and provide detailed composition information on different areas of the body including arms, legs and torso.
  • It measures bone density as well as visceral fat (fat around the organs), so can help detect health risks.
  • With my particular experience at Measure Up – an exercise physiologist sat down and gave me a detailed overview of the results with suggestions for goals going forward. There’s also the option to be given more detailed training plans based on results.

Why wouldn’t you want a DEXA scan?

  • The scans are pretty expensive (around $150-$250 in Australia) so unless you’re loaded with money, they’re not that accessible for the general public.
  • Despite giving details about limbs and torso, this particular scan doesn’t show results for the chest or back areas, unlike the skin folds method.

My thoughts on the DEXA scan

I found it really interesting to see a visual description of my body composition and also get some more details and advice from a professional. I’d recommend the DEXA scan to anyone who might be interested in their bone density and whether they might need to tweak their training to improve it. The DEXA scan is seen to be very accurate, but my overall readings are very similar to my skin fold test done on the same day. So, the average gym-goer on a budget might be better off just trying the skin fold method.

A snapshot of my DEXA  body fat % results:

The results give a breakdown of fat and lean tissue mass in the left and right arms and legs, and the torso. The exercise physiologist explained that I had no significant imbalances between limbs. My visceral fat and bone density were both healthy readings.

 


DEXA scan November 15 result: 19.4% body fat at 57.3kg

(I had eaten breakfast and lunch by this point so weight had increased)


Body fat reader on a scale or hand-held device

In my last blog I spoke about how tracking only your weight (and not body fat %) can be an inaccurate portrayal of progress. Saying that, some scales do have body fat readers built in – called Bioelectrical Impedance Devices. There are also devices that you can grip with your hands that have the same technology. The idea is that they send a gentle electric current through the body, distinguishing where the fat is because it has a different electrical resistance than other tissues.

The theory sounds good, but what are the issues?

  • Factors like hydration status can change the reading – so if you measure yourself after a workout when a bit dehydrated, you may end up with a lower % than if you had measured before the workout, for example.
  • Different types of devices can give different readings. If you use one on a scale, the electric current will go through your legs, and with a hand-held device, your arms. Depending on where you hold fat, this could cause inaccurate results.
  • The reading only gives an overall percentage and doesn’t specify any sort of breakdown across your body.
  • Results just generally tend to vary with this method. My results using the scanner on my scales were around 2% higher than the other methods I tried.

Not the best write up. Why would I use a Bioelectrical Impedance Device?

  • It’s cheap, and very easily accessible either in your own home or at a local pharmacy.
  • Like any measurement, if you consistently use it – even if the results aren’t completely accurate – you can still track change. If the numbers are going down (even if they’re not right) – you still know you’re going in the right direction.

Bioelectrical Impedance Devices – the verdict

My experience is that they’re not reliable. I’d even guess that some of the machines are actually just taking an average of your height as a body fat estimate (maybe a bit of speculation from me). But, if you don’t have access to any other method, they’re probably an OK plan B (or C, or D).

Tips for using a Bioelectrical Impedance Device

  • Keep conditions consistent each time for the best results – use at the same time of day, before breakfast for example, and if you’re a woman, at the same time of month (so any factors such as the menstrual cycle won’t vary between readings).
  • Take the results with a pinch of salt 🙂

 


Bioelectrical Impedance Device November 15 result: my scales gave me an estimate of 22% body fat at 56.2kg

Over 2% higher than the other methods


The final verdict on body fat % measurement methods

I’ll start by saying that no method of measuring body fat is 100% accurate – although some are more accurate than others – and from experience it’s quite difficult to get access to the more accurate tools. If you have the extra cash and are curious about your bone density / the details of your body composition – get a DEXA scan. If you have access to callipers – I think this is a great method to pursue for an overview of your entire body and one used by lots of fitness professionals – but it needs to be performed by someone who knows what they’re doing. Failing access to these, a more generic Bioelectrical Impedance Device is better than nothing.

Whatever method you use, the key is to stick to the same one throughout to maintain consistent results – and ensure the conditions are consistent too. The actual reading might not be completely correct, but if the numbers are still going down, you know you’re making progress. And progress is the main thing – no one really cares whether you’re 13% body fat unless you’re competing, let’s be honest!

 

Any questions on cutting, nutrition, fitness or anything else – feel free to slide into my DMs or send me an email at hello@katebrown.blog.

 

Leave a Reply

Your email address will not be published. Required fields are marked *