Keith - question about body fat percentage

My trainer rechecked my body fat percentage on the handheld meter tonight. Now, I know they are notoriously inaccurate, but...I have dropped (by his scale) 9 lbs in 2.5 weeks, but only .9% body fat.

What does that mean? Am I losing muscle?

I have contacted local colleges to see if they do hydrostatic testing and am waiting to hear back so the handheld meters are as good as it gets for now. Any insights you have are really appreciated. Thanks!

Laurie

I wouldn't spend money on hydrostatic testing until you get closer to goal.

You could very well be losing muscle but what is probably really happening is that when you lose weight you don't get to pick where it comes form. So it could just mean you didn't lose much from the test site. It could mean you are losing weight distributed over your whole body.

I wouldn't put a lot of trust in the measure. You can get a body composition scale for less than the cost of hydrostatic testing. Not as accurate but closer than the pinch test.

Not Keith, but a couple of readings a couple of weeks apart aren't very meaningful. These impedance devices, which measure the impedance between your feet or hands, are sensitive to your hydration, so they will vary some during the day (my scale will vary 4-5 percentage points between first thing in the morning when we are typically dehydrated from overnight, and late afternoon when we are typically optimally hydrated. To get the most from these scales, one should weigh at the same time of the day, and ideally, every day and take a moving average over a couple of weeks (add the readings of each day for two weeks and divide by 14, then the next day drop off the number from fifteen days before...) I never got that fancy, but just noted when the whole numbers changed - if my daily readings were in the 31's and 32's  the significant changes was when I started seeing numbers in the 30's and stopped seeing numbers in the 32's. Doing it that way, the whole number correlated pretty closely with the hydrostatic testing that I had done.

Individual readings at the doctor's office or with the trainer are of limited value unless they are done often enough to establish a trend. On total accuracy (and accuracy of measurements can create even greater religious/philosophical disagreements than the total carb/net carb debate!) the body comp readings can vary depending upon whether the measurements are taken between the hands or the feet - pear shaped people who hold more of their fat low will read a bit fatter between the feet than between the hands, while apple shaped people who hold more fat around the middle will be the opposite; the best impedance scales read between both the feet and the hands to average out that error.

So, you are right in that they aren't the most (instantly) accurate devices, but they are useful for monitoring trends, and can be checked occasionally along the way with a dunking, bodpod or dexascan.

Thanks for the great answers!

Not Keith either, but I've done a lot with BF.

I rarely disagree with Keith, but I do here - I think if you know your BF% now, you can set a realistic goal.  For example, if you weigh 200 lbs and determine that your BF% is 40% then you know you have 80 lbs of fat that could potentially be lost.  Now you have to retain some, healthy for a woman is typically around 25%.  Knowing that, you could easily set a goal of 160 lbs total weight and 40 lbs fat (40/160 = 25%), and then test again as you get close to see if all the parameters are the same. NOT knowing that means your goal weight is a pure guess and could lead to needless frustration.  Setting your goal based on a healthy body fat rather then an arbitrary "weight" number seems to me to be a smarter way to do things, and its never too early in the process to have your goal set properly.

I wouldn't even bother with the meters.  I've checked them against more accurate methods, and they're pretty useless - perhaps it has something to do with us metabolically challenged folk - I don't know.  What I do know is that my Tanitia scale has not varied from a reading of 16% BF for a year, but more accurate methods have shown my steadily decrease to 10.9% over that same time.  If I believed the tanita, I'd be sure I was losing muscle - when in fact i've lost fat and added muscle during that time.

I highly recommend the DEXA scan for the most accurate and least messiness.  These scans are often used for determining bone density (not a bad idea for weight loss folks either - calcium can be an issue).  But they have a "mode" for body composition. You have to be certain to ask for a full body composition, or you might just get bone density - that's what happened to me the first time.  The DEXA does an actual measurement of all your tissue using a low-dose xray type mechanism.  I believe it's considered the best for body composition analysis at this time.

The DEXA cost me $75 and I was in and out of the radiologist office in 15 minutes.  

Another option that may be less expensive is a BodPod.  It uses the same principal as hydrostatic weighing but uses an air chamber instead of water.  I did this too, and the results seemed in line with the DEXA.

I highly suggest doing an accurate BF% a couple times along your journey.

Tom

 

Thanks, Tom! Good tip on the DEXA scan.

I had been looking for the hydrostatic testing at a local university. One of our fellow OH members had it done for a great price ($40, if memory serves) at a university near her. I figured, at this price, its something I can have done a couple of times over my journey.

Laurie

Yep - that's a good option - I did BodPod for $75 for 2 sessions... but Hydrostatic or DEXA will be more accurate.

Where would I look to find the Dexa or Bodpod testing? That does sound interesting to do a couple of times along this journey?