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Why measuring your Body Fat Percentage DOESN'T tell you how fat you are!

Why measuring your Body Fat Percentage DOESN'T tell you how fat you are!

Many of our clients come to us for Body Composition Analysis, with one question in mind... "What's my Percentage of Body Fat?" - I actually have fairly regular requests where the client asks me specifically how much it costs for me to ONLY tell them their PBF! Of course, I refuse to do this because Fitness Key is a COACHING service, not a 'scanning service' that is willing to send their clients away more confused than they arrived! Ok - Off my high-horse now... let me explain WHY this single metric, when viewed separately to the collection of information that actually creates it, can be very misleading!

Simply put, your Percentage of Body Fat is not a statement of how fat you are - it is a statement of how fat you are, compared to how 'everything else you are'. The question of how fat an individual is, can really only be assessed by measuring the Body Fat MASS (the total grams of fat in the body). 

To illustrate my point, lets compare two females (that are incidentally both 38 years old and within 1.5cm of the same height).

First, have a look at the image below... 

The female shown above has a body fat mass of 31.9kg and their Percentage of Body Fat is 38.2%

Now compare the first image with the following one...

This second female has an almost identical Body Fat Mass (100g difference) - she is exactly as 'fatty' as the first female, however her body fat percentage is only 33.6% - 4.6% lower than the first female!

If both individuals are exactly as 'fat' as each other, why is there such a difference in the Percentage of Body Fat? The answer is simple...

Our second female has a total of 11kg more Fat Free Mass (non-fat components) in her body - consisting of an impressive 6.2kg more Skeletal Muscle Mass, plus more adequate protein, mineral (including bone mineral) and hydration levels. 

As you can see, both individuals still have a journey in front of them, as both respective Body Fat Mass volumes are well beyond the desirable levels, however the second female in our example is considerably closer to the healthy body fat percentage range (18%-28% for women).

On a slight but related tangent, it's also worth noting the differences in our two females Basal Metabolic Rate (BMR = the baseline energy consumption of our body at ABSOLUTE rest, in 24 hours);

  • The first female with the lower Muscle Mass has a BMR of 1488kcal
  • The second female with the higher Muscle Mass has a BMR of 1727kcal (239kcal more)
  • Now, 239 calories might not seem like much, but in very simple terms (and I do mean VERY simple); If both of our females maintained the SAME diets, lifestyles and training regimes - and MAINTAINED their respective amounts of muscle mass, the second individual should burn a conservatively estimated 5-8kg of body fat per year, more than the first. Of course, sweeping statements like that are based on a combination of various opinions and texts - and outcomes are effected in one individual to the next, by too many confounders for this blog post to address - but I hope you get my point... MUSCLE BURNS CALORIES, EVEN AT REST!

    Considering all of the above - and knowing how hard it can be to grow muscle mass, I know which position I'd rather be starting my 'weight loss journey' from!

    I hope that if nothing else, this blog has taught you that it's actually your MUSCLE-FAT RATIO that has a greater effect on your overall health (and long term sustainable weight management prospects), than your Percentage of Body Fat.

    I'll leave you with one a few more example scans and let you do the math... Again, both females are the same height and they both have identical Body Fat Mass - but this time the HEALTHIER one is actually 12 years older than the other (42 vs 30). 

    VS

    Thanks for reading!

    Go and GROW!

    Steve Burden.

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