Thoughts on Improving My Body Fat Data Collection

I have tracked my weight changes throughout my lifetime, and thanks to my baby book, various medical record requests, and information I kept in notebooks, I now have a lifetime weight history graph that I showed in my recent presentation at QS15.

Weight history purple and aqua2

For a long time, I have wanted to be able to track my body fat percentage in a reliable and detailed way, but my historical body fat data is sparse.  I have a few bioelectrical impedance (BIA) data points from 1998-1999 and a few recent caliper measurements.  I used the Navy method (a body circumference-based estimate of body fat) to estimate progress during various weight loss efforts, but that measure is also based on numbers derived from population averages and may not be accurate for all individuals.

I now use a Withings wireless scale each morning to monitor my weight, and it also utilizes BIA to estimate my overall body fat.  All body fat methods are known to be sensitive to body water content, which is why you will often see the suggestion to step on a BIA body fat scale only after 1) drinking a pre-specified amount of water, 2) waiting 30 minutes 3) urinating.  I prefer to eat and drink shortly after I get up, so following that protocol is not very convenient for me.  My hydration status and body water distribution changes from being in a prone position overnight definitely impact the accuracy of my morning body fat measurements.

I observe that my scale overestimates my body fat first thing in the morning, with a 3-4 point difference typical between measures taken upon waking (4-4:30 am) and measures taken slightly later (6-6:30 am).  In some cases, I have seen as much as an 8-10 point reduction when comparing an early morning fasted measurement to one taken several hours later. Granted, my scale is a few years old, but for me, it seems that these measurements are really only useful for monitoring general trends and not as absolute or accurate measures of my body fat status.

Better Methods for Body Fat Assessment

DXA (or DXA) and hydrostatic (underwater) weighing are known to be more accurate body fat estimation methods than calipers, circumference, or BIA measurements.  Unlike most other methods, DEXA also provides compartment-specific body fat percentage information with legs, arms and trunk broken out separately. This information about body fat distribution is one important factor that contributes to people looking different despite having the same overall body fat percentage.  Other factors include variation in bone structure, muscle size and shape.

The most useful information I  encountered on this topic is a pair of Venus Factor Immersion podcasts on the subject.  John Barban and Brad Pilon host the Immersion podcast series for their membership-based workout and diet program clients.  I’ve been using their workouts since 2011, bought access to the Immersion program in 2012, and have learned a tremendous amount from listening to their various podcast series.  In this two parter, Brad and John discussed working with various clients whose body fat distributions varied and how this impacted their look at lower body fat percentages.  Brad blogged about the topic here.

After hearing so much about DXA from Brad and John, I finally had a scan in early 2014 at UNC Wilmington with Dr. Wayland Tseh to assess my own body fat percentage. It revealed what I had long suspected from the imperfect data I had.  I’m on the high side for lean body mass, about 2 standard deviations over the mean for women of my height and weight at the time of the scan.  This is not very surprising given my body build and training history. I have always looked more athletic than most women my height and I have been weight training since age 13.

On the morning of my DXA, I only drank water before the test as instructed.  I weighed 127.5 and my Withings scale assessed my body fat at 25.6% at 4:50 am.  My DEXA just a few hours later measured my body fat at 17.5% at 127.4 lbs, which agreed exactly with a Tanita clinical-grade BIA scale at the lab. My body fat was surprisingly symmetrically distributed. My arms were my leanest part at 14.2%, my trunk was next at 15.4%, and my legs were my least lean area at 22.4% each. My left side had slightly more lean mass than my right, which I found surprising given I am right-handed, but Wayland said that was very typical.

Going forward, DEXA data in hand…

I don’t trust the body fat data that I have the most of (BIA), and all the other methods I have tried have inconvenient drawbacks, but as my maintenance period stretches on, I have felt more and more like I needed a way to collect better data on my body fat percentage. Cost and time prohibited me from heading to Wilmington to get DEXAs on a regular basis and I was hoping that eventually I’d encounter a tool that I could use at home. Enter the Skulpt Aim body fat analyzer, my new favorite toy!

I first came across the Aim online a few months ago, and was dying to buy one.  However, since I had just purchased a Fitbit Charge HR and Push Strength band, my husband forbid me to spend money on yet another tracking device.  (To be fair, I have been using both of those devices regularly since their purchase.)  But after I had the chance to try out the Aim at the Skulpt booth at QS15 last month, I finally convinced him!

There are many detailed reviews of the Aim out there so I won’t try to replicate those (one of my favorites is here if you are interested in more details). In short, the device uses electrical impedence myography (EIM) and claims to be comparable to DXA, more accurate than calipers, and much more accurate than BIA for testing body fat percentage.  It was initially developed to assess people with muscle diseases in the clinic. The Aim provides local body fat percentages and region-specific muscle quality (MQ) scores, which greatly interest me as an additional measure of change over time.  When you’ve been training with weights as long as I have, any metric that can give you insight into incremental progress becomes extremely useful!

Unfortunately, i’s been a bit of a saga keeping a Skulpt in my hands to use reliably so I have only been collecting data for a few weeks.  Below, I share what I learned from the experience of getting my device in the hopes that you can avoid some of the mistakes I made.

Lesson #1:  check carefully for the best available price before you order.  I recommend checking for referral links on Twitter to find the lowest price.  I checked Skulpt’s site first, and they listed a price of $199, same as Amazon (although I have seen it for as much as $240 on Amazon recently).  I decided to order it Aim #1 from Amazon, but the day after I ordered it, I visited the Skulpt site and saw they were now offering a special deal for $149.

Amazon didn’t price match so I ordered Aim #2 from Skulpt and a return label from Amazon.  Later on that day, I found a referral link for the Aim direct from Skulpt on Twitter for the lower price of $129.  Skulpt won points with me by honoring the lower price and refunding me $20.   (With the $70 I saved, minus $6 return shipping to Amazon, I purchased a Bluetooth-enabled Polar H7 heart rate monitor for measuring heart rate variability (HRV), but I’ll save that topic for a later post!)

(By the way, if you want to get a good deal on an Aim, you can use my referral link here to purchase.  It’s a definite win-win.  You get a lower price, and I get a $20 Amazon gift card!  You also get your own referral link when you purchase.)

I will confess I did open Aim #1 from Amazon and try it out. I found the packaging to be most impressive-without a doubt, the nicest I’ve ever seen for an activity monitor or fitness related device.  The green and black smooth cardboard and plastic layers of the packaging were simple to take apart and put back together without damaging them so I’m definitely going to keep the package to store and transport the device.

My first set of measurements with Aim #1 estimated my body fat at about 19.9% using a four site measurement of right bicep, right tricep, right abs, and right thigh.  I found this measurement to be quite believable at my current weight.  My first impression was that the device was easy to use.  It has a select button on one side and an up-and-down button on the other side.  Although some reviewers have stated that a touchscreen would’ve been preferable, I can understand why they didn’t go that route after many failed attempts to use touch ID on my iPhone with wet or even slightly damp hands.  The back of the Skulpt device has to be sprayed before every use so damp hands would definitely be an issue with a touch screen.

I sadly packaged Aim #1 back up to send back to Amazon since the return had to be completed within a few days.  Later that evening, Aim #2 arrived from Skulpt.  I charged it and completed another 4 site measurement, which gave me a result of 17.5% this time, which seemed low, but it was taken in the evening, as compared to my previous morning measurement. I also used the device on my husband, who came in at 13.8% overall body fat which also seemed believable.  Interestingly, our overall muscle quality scores were identical at 128.

Lesson #2:  Be extremely careful when using the device and DO NOT drop it!!! Less than two hours after receiving Aim #2, while I was using it to measure various muscles not included in the four point overall measurement, I dropped it on my kitchen floor and the screen went blank.  Despite repeated attempts to charge, turn it on and turn it off, I had to face reality that the screen was nonfunctional.

I sent an email to Skulpt right away explaining the situation and asking what I should do, and received an automated response indicating they were receiving a high volume of email and would respond soon. Two days later, I emailed again and received the same response. After waiting another day, I contacted someone I had met from Skulpt via LinkedIn and received a response on my original ticket.  She noted that if the device was charged but the screen wasn’t working, it was probably broken, and damage due to dropping the device was typically not covered under their warranty.  However, they again won points with me for customer service by making an exception and sending me a return label and a replacement device.

All in all, at least 2 weeks elapsed between receiving and dropping Aim #2 and receiving Aim #3. I know dropping falls under the category of “user error,” but I’ve now read at least two other reviews that mentioned dropping the device.  In one case it “popped open” and in the other it “didn’t look pretty” after dropping, but at least in those cases the damaged Skulpt could be snapped back together and still functioned. According to my correspondence with Skulpt support, dropped devices aren’t a common user problem. I am guessing I had the bad luck to drop it at an angle that broke a critical internal connection. I definitely won’t be doing what I have seen users online recommend-using Skulpt after a shower when most body areas are wet! I will avoid bringing the device into any room with ceramic tile or hardwood floors.

Despite this rocky start, I really adore this device and the unique data it provides! Without a doubt, it’s one of the most useful tracking gadgets I have ever owned. In my next post, I’ll be sharing details about my early use of the Aim and some of the things I’ve learned:

  • How to get the most reproducible data out of your Aim
  • Which areas are the easiest and hardest to measure
  • What areas of my own body are leanest and which need more work

To order your own Aim, you can click on my referral link here.


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