We’ve said this before but I just want to be clear from the outset that we don’t have any affiliation with BodyScan and we don’t make any money from you guys using their services. We just think it may be a useful tool for some of you to incorporate.
What is a DEXA Scan?
DEXA is pretty much the gold standard for accurately measuring body fat percentage. It uses x-ray technology to pinpoint your fat tissue, muscle tissue and bone. DEXA scanning machines were originally developed to measure bone density in patients at risk of osteoporosis and you will find them in most hospitals.
What are the advantages over traditional skin fold measurements?
- DEXA is much, much more accurate. Skin fold measurements are prone to human error. Taking a measurement 1cm away from the correct site can result in markedly different results. Taking a pinch in a slightly different way has the same effect. What’s more, if you’re not already fairly lean (<18% for guys and <22% for women) this method works poorly (some of you have already seen this first hand!) and tends to massively under-report body fat %.
- Skin fold measurements only account for subcutaneous fat (the fat under your skin) and give no indication of fat beneath this layer, particularly visceral fat (the fat around your organs).Visceral fat is an incredibly important health marker, so having this data point is very useful.
- To give you an idea of the discrepancy between DEXA and skin fold measurements: I measured at 13.1% on DEXA and 8.5% on skin folds and I did the skin folds measurement when I was noticeably less lean than when I did the DEXA… I also have very low visceral fat so most of the discrepancy is actually in the accuracy of the measurement of subcutaneous fat (the fat that skin folds are supposed to capture!).
- DEXA scans give you much more granular data than skin folds. As you’ll see below, the DEXA scan tells you where exactly you are storing your fat, how this compares with population averages and how this distribution reflects your hormonal profile. You can also see how much lean muscle tissue you have so you can track how much muscle you have gained or lost. As I said above, you can also see your bone density and your visceral fat reading.
How can I get a DEXA Scan?
We have set up a special CrossFit City Road discount with BodyScan in Marylebone. To get booked in, email Phil at email@example.com copying in firstname.lastname@example.org saying you want to book a scan and that you are from CrossFit City Road.
The best thing to go for is two scans with no consultation.
How much does it cost?
2 scans without a consultation should cost somewhere around £170 though the price may vary (and I’m not sure on the details of why or how to be honest).
What do you get?
Below are my test results from a scan a while back.
- The table on the left shows your body fat % data. The overall score is under subtotal which is 13.1%. The Total reading is not traditionally used because it includes the head which is predominantly fat (your brain is mostly fat!). You can also see your percentages for different body areas. You can see here that my arms and trunk are a bit leaner than my legs are. This distribution will vary between people.
- Under Total you can seen the mass figures. You can see on that line that I am carrying about 12kg of fat (ewww!) and about 75kg of lean tissue (this includes bone).
- The figures on the far right of the table under %Fat Percentile show you how your body fat percentage figures compare with the general population. YN figures compare you with the “Young Normal” data set (i.e. the leanest data set) and AM figures compare you with your particular “Age Matched” data set, which for me is 28 year old white males (the data sets vary in age and ethnicity too). Here you can see that less than 2% of Young Normals and 1% of Age Matched individuals have lower body fat percentages than mine.
- The chart on the top right shows graphically how your body fat percentages compares with the population. The middle line is the mean value for body fat percentage and the two lines are two standard deviations above and below the mean. If you don’t like statistics all this means is that the coloured band represents 95% of the population. Clearly you want to be placed towards the bottom of this band and happily I am below the band.
- In the table below this labeled Adipose Indices the most relevant numbers are the Android/Gynoid ratio and the VAT (visceral adipose tissue). The Android / Gynoid ratio measures whether you are storing fat like a typical male or typical female. Guys want a number above 1 and women below 1. The number might help you determine if you have some atypical hormonal business to sort out. Much more important are the VAT numbers. The most relevant one is Est. VAT Area where ideally you want less than 100cm^2. I was very happy with what is apparently an extremely low 45!
- The final table is the Lean Indices table which shows you how you compare with the population in terms of how much lean mass you are carrying. You can see here that I have more lean mass than 87% of the population and more lean mass in my limbs (Appen. Lean/Height) than 93% of the population.
- There is less data on this page, but it is still interesting. The graph shows where you compare with the population in terms of bone density. I was pretty much off the chart on this measure, the band again representing 95% of the population. In the table, the relevant numbers are the Total under BMC, which gives the weight of your skeleton and your Z-score which tells you how many standard deviations you are away from the mean. My skeleton weights about 3.7kg (the typical male skeleton weighing apparently 2.5kg) and my Z-score was 2.7 S.Ds away from the mean (that’s a lot – remember 2 standard deviations includes 95% of the population and 3 includes 99.7% of the population!).
I hope this gives you guys a better idea of the usefulness of getting a DEXA scan. It is certainly not essential, but if you like data and you want to keep track of what is really going on, this is a great way to do it!