Dramatic Fat Loss or Smoke and Mirrors?

I recently developed an educational program for my buddy’s gym just down the road from Grand Rapids in Holland, MI.

In a weekly presentation lasting roughly 75 minutes, I deliver a boat-load of information to help both fitness-newbies and seasoned gym-rats get the most out of the time they have available for training.  While I see the information as ‘basic’, my interpretation of “eat right and exercise” (apparently) goes way beyond what most people learned in their high-school gym class.

When I checked my inbox earlier this week and read the following email, I had to chuckle…

I went to your new member orientation at Flex Fitness, and have been following the diet as best I can and also trying to work on my stability by lifting with low intensity (3 sets of 15). So far I’ve lost 9 pounds and dropped my body fat percentage 9% in just 2 weeks.(9 lbs. is not 9% of my body weight, so I must have gained some muscle as well)

While I’m all for using testimonials in my marketing efforts to show others just how valuable a trainer/coach/educator I can be, I just couldn’t let him go around sharing his experience with everybody.  I like to think I’m pretty gosh-darned good at what I do, but imagine the unrealistic expectations people would have of me if word of my magical ability to produce 9% fat loss in just 2 weeks got out!

I mean, if I was shooting an infomercial for a crappy abdominal gadget, I suppose I’d be tempted to milk the hell out of it, but I’m just not made up that way.  (yeah, I know… sometimes I even surprise myself.)

So, for your education/entertainment, here’s my response…

Sounds like you’re off to a GREAT start!

While you probably did start to eat away at your bodyfat stores – and may even be noticing some increases in your strength, I’m going to do what I do best and give you something to consider…

This is not because I want to be the burster-of-bubbles (and certainly not to deter your from continuing to work at getting ‘lean & mean’), but what you’re most likely seeing in such a short time is the difference a change in hydration level can make.

I don’t remember if I told you about the marathoner I worked with during your orientation session…  Before a race, he measured in around 12% bodyfat.  26.2 miles later, he was in the low 40’s.  It’s not likely that he got 30% fatter while running a marathon.  Instead, he became dehydrated and it completely obliterated any degree of accuracy of our measurement tool – bio-electrical impedance analysis (BIA) – might offer… The one we used was similar to the popular Tanita body comp scales, but a hand-held version.  I’m suspecting you used a similar device?

Assuming you did, essentially, you achieved what the marathoner did in reverse… hydrationally speaking, anyway.  Many people start out under-hydrated, which can give an artificially high reading when using BIA as an estimation tool.  By eating regularly, drinking plenty of good fluids and balancing things out through training for the past couple of weeks, you now have a much more accurate reading.  Make sense?

You know how water is a good conductor of electricity? Try throwing a hair dryer in a bathtub full of water and you’ll quickly find out! [note: please don’t REALLY do this!]

If you throw the same (hypothetical) hair dryer in an empty tub, the electricity won’t go very far.  This is effectively how BIA estimates work.  It takes some basic variables (height, weight, age, sex) and measures the speed at which the device completes the circuit (sending a micro-current through your body) to come up with a number that is *supposed* to be within a range of +/- 2.5% accuracy when compared to others of similar height/weight/age/sex.  Problem is, when hydration can’t be controlled or accurately measured, it’s likely that you’ll see some drastic swings as H2O levels change.

Now if you used skinfold calipers on yourself, there’s also a degree of human error to be expected, so given the dramatic change in your numbers, I’d also question the accuracy of that method.

Hydrostatic testing has long been considered the “gold standard” of estimating body composition. This involves exhaling every last bit of air you can squeeze from your lungs, then being weighed while you are completely submerged under water.  That’s not a natural way to go diving, ya’ know?

If you really need 100% accuracy, you’ll have to wait until you’re dead, then have someone boil you up in a vat of water, skim off all the floaty-stuff at the surface – weigh it and then subtract it from your total starting weight.

[note to the mentally deficient and/or cannabalistic serial killers with an interest in physiology: I’m not recommending the above ‘technique’, I’m only trying to impress upon you the fact that 100% accurate measurements aren’t really all that important outside of a research environment.]

It is for reasons like these I recommend the use of regular (bi-weekly/monthly) progress photos AND a favorite outfit/pair of jeans/etc as tools to measure MEANINGFUL progress.

Of course, if you DID actually drop 9% body fat  in just two weeks, I’d love to make you the ‘poster-child’ for my services!!!  If I can help you accomplish that from nothing more than a spoken presentation, imagine how good the results would be if I actually designed a complete training plan for you!

Let me know what the numbers say in another week or 2.  Barring any dramatic swings in your hydration level, that should give us a much better indication of your progress.

[note to the FTC: how’s THAT for truth in advertising?]



  1. Thanks for the levity Joe. You ever tell people to see about getting a DEXA scan? More and more are being ordered as HMO’s try and reach their Bone density screening goals. If they are getting one done already, I am sure they can ask for the fat free mass figures.


    1. I second the DEXA scan consideration. And the client will get a nice breakdown of where that fat / lean mass is concentrated (e.g., legs, arms, torso).


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