Body Fat Percentages

We often refer to body fat percentages when deciding how close individuals may or may not be to their ideal body weight. But is this measure realistic?

I think there are two main approaches which must be taken when deciding if tracking body fat percentage is a good idea:

1) Is it even possible to measure your body fat percentage accurately or consistently?
2) If it is possible to measure body fat percentages accurately and consistently, is it even a meaningful variable?

The two questions posed above are of crucial imporance and I will explain why this is so. Looking at the first question, is it possible to accurately measure your body fat percentage in the first instance? I am not sure it is. It would be interesting to know how such measuring devices are calibrated. I recently ran an experiment. I had my body fat percentage assessed by healthcare professionals using what I am told is some of the most accurate equipment available at a private hospital facility. The measurement reached was under 10% total body fat. I am not totally sold on this figure because part of the method of reaching this figure involved entering my age and the number of days I exercised each week.

Already, those parameters show weaknesses in the measurement system. If the device is accurate it should not need to be told those things, should it? For instance, age ranges for these fat measurements are in 4 or 5 year segments on most machines. This means that if I rate my age as 35 years old I get a very different reading to if I register my age as 36 years old. I am only three weeks away from my 36th birthday and I do not envisage my body fat changing over the next three weeks. So this methodology is totally flawed when viewed in the cold light of day.

Further still, if I exercise 5 times weekly I will be given a lower body fat percentage than if I exercise once or twice weekly. Again, anyone with even a cursory knowledge of human physiology will see the obvious flaws in this. If I walk five days a week my body will be formed very differently to if I lift heavy weights five times a week. There is also the aspect of exercising correctly. If you don't exercise properly your body may be little different to that of someone who does no exercise at all. So the number of days which you exercise on each week is a loaded variable. Again, totally meaningless.

Just to prove my point I went to my local gym shortly after the hospital measurement and had an (incidentally) overweight teenage 'personal trainer' measure my body fat using the device housed at the gym. This device claimed my body fat was 18% - which the girl went on to tell me was "really good!" Here we have a 10% variance between two different branded measuring systems. Obviously these devices are flawed.

That shows why the first aspect relating to the accuracy of these devices is so questionable. The next aspect to consider is the meaning or significance of these measurements. I'll explain this in more detail. Let's, for the sake of argument, assume that it is, indeed, possible to accurately measure percentage body fat. I know it's not possible, as I've just demonstrated, but let's pretend it is - in order to demonstrate the second point I've made.

If we can measure our body fat does it actually mean anything? I say, "no." I can easily demonstrate this with a mathematical example. Consider two men, both 5' 10" tall - who train in totally different ways. If one is a marathon runner and the other a bodybuilder, they will probably show totally different physiques. If the marathon runner weighs 60 kgs and is measured at 10% bodyfat, then this would mean he had 6 kgs of body fat on him.

Consider the bodybuilder now. If he weighs 100 kgs and also measures his body fat with the same hypothetical body fat device and finds it to be 10% as well, this would mean he carried 10 kgs of fat on him.

The figures speak for themselves, the two men are the same height and are shown to have an identical body fat percentage. But one man carries 6 kgs of fat and the other 10 kgs of fat (about 40% more fat!). The body fat measuring device (and indeed, the concept of reading body fat measurements) will say both these men are equally healthy and will also suggest that both these men are equally lean - which is totally untrue. In addition to this, the bodybuilder will actually need to gain more fat in order to reach 15% body fat than the marathon runner does.

The two hypothetical men are of similar height, so their total mass of fat would matter. It is erroneous to say that two people of the same skeletal structure and height can carry very different amounts of fat and yet still have the same leanness and health parameters. Fat secretes hormones and enzymes, some of which can be disease-causing if they break certain thresholds. These thresholds are determined by the total mass of fat present. Also, fat stores most of the toxins within the body and the more fat one carries, the more potential toxicity that individual may be subjected to. These factors combine to cause metabolic diseases, heart disease and cancer. Fat is dangerous in high amounts on the muman body and every kilogram counts.

For the reasons pointed out above I think it's fair to say that measuring body fat is not the best way to judge your health and leanness. It may make more sense to track changes in body weight and to match them to pictorial progress (how lean you look in photos taken during a period of weight loss) and actual limb and body measurements (how thick are your arms, legs and waist). If the waist narrows, while the arms and legs do not, it is safe to say it is most likely that you are losing fat.

I suggest you track more reliable measurements if you want to truly check your progress and leave the fat percentages to the realm of theory.

Idai Makaya
www.idaimakaya.com