Questions Re. Body Fat Measurements

T

Turn-a-Round

0
Hi all...

I'm new to this forum and I have a couple of questions that I'd like to ask regarding body fat and the measurements of it.
I go to the gym 4times every week and for the last 6weeks, I have used a machine at the Leisure Centre I go to that measures my weight, height, B.M.I., body fat percentage and body fat mass - Results below:

WEEK 1 WEEK 2 WEEK 3 WEEK 4 WEEK 5 WEEK 6
WEIGHT 11st 9lb 11st 7lb 11st 8lb 11st 10lb 11st 13lb 11st 10lb
B.M.I. 23.5 23.3 23.3 23.7 24 23.8
BODY FAT % 11.10% 10.40% 10.70% 12% 11.90% 16.40%
BODY FAT MASS 8.2kg 7.6kg 7.9kg 8.9kg 9kg 12.2kg

I haven't noticed any deterioration in my my physical fitness or in the appearance of my physique but I'm really quite alarmed at the rise in my body fat percentage and body fat mass.

Time for my questions... :)
Are machines that measure body fat percentage and mass accurate, or is there some ambiguity with these?
If the results above that I've been given are accurate, are body fat measurements of 16.40% and 12.2kg too high? Should I try to reduce these to a lower level?

Thanks to everyone who's read this.

Any replies / advice would be greatly appreciated.

Kindest regards,
Ric
 
The accuracy will depend on the exact devices used. If the gym's using bio-impedance (where they measure electrical currents running through your body), then the reading can be out by 4%....if everything's done correctly. That includes setting up the device correctly, but it also includes you having gone through some fairly strict protocols for hours beforehand (which I'll assume you haven't, if for no other reason than that I assume they haven't told you what these protocols are). That means that if you had 10% body fat and everything was done correctly, the test could show anything from 6-14% as your results. At a gym I used to work at, we had a little handheld body fat % device, and I used to have people do it 3 times in a row, then look for trends and averages in the results to assess what the device was really telling us.

In the final week, you're weighing in 3lb lighter than the previous week, yet are measuring in with an extra 3.2kg (7lb) body fat. Something is definitely off in that equation. It would take extreme circumstances for those changes to occur together in the one week. I think it's much more likely that this is just human and technical error doing its thing. Adding up all your results and finding the average suggests that you're at about 12% body fat, give or take. The trend indicates about 10-12%, with 16.4% being an outlier.

That being said, let's assume for argument's sake that you are in fact at about 16% body fat. For a male, that's a normal, healthy place to be at (although you wouldn't want to be much higher). For a female, that's very low. For a male you might see a bit of an outline of the abs at this level. For a female you'd be shredded. When training for aesthetic purposes, I don't recommend men be above about 12% body fat unless they really know their bodies, because we enter what I call the dead zone from about 12-18% bodyfat. This is where we've got too much fat to be ripped but not enough fat to really obscure our muscle mass, so we can add a heap of fat in this range without gaining muscle and think that it's all lean mass, and we can lose a heap of fat in this range and this that we're losing muscle instead. But that's the only real problem with this range. Physically it's fairly healthy to be anywhere from 8-18% for men, and we perform pretty well athletically in that range, too.
 
Agreed with Goldfish. Those bodyfat scales will give you a varied reading depending on how hydrated you are as well as how much food you have in your stomach. The ones with the handheld device as well can give a slightly more accurate reading, but it's still subject to the same type of error.

I would say that the best method of using those scales, if you're going to keep doing so at all, is to minimize all the variance. Preferably, take the measurement at the same time of day, every day (first thing in the morning is best, but that really only works if you own one at home) be consistently hydrated, and measure at least a couple hours after your last meal.
 
Stand on scales are less accurate and will become more inaccurate if going from unfit to very fit. This is why good ones have setting for fitness that help a small amount.
Unless you have ready access to an MRI machine your body fat monitoring will not be accurate. Even water weighing is vague. If going for aesthetic, use the simplest aesthetic monitoring tool the mirror. If you use this in a totally unbiased manor perfectly evenly, report yourself to a doctor, because you're not human.
 
Adding to the above, arguably a better tool than the mirror is the camera. Like all things, to make it as reliable as possible you want to recreate the circumstances as accurately as possible -- same time of day, same lighting, same pose etc.
 
Thanks to you all for your replies.

Goldfish - I'm glad that you picked up on the fact that I was given readings of 3lb lighter but with 3.2kg additional body fat mass. I thought that this was very odd to say the least.

CrazyOldMan - I didn't realise that stand on scales are less accurate if one has gone from unfit to very fit. This is very interesting to me though as I'll be the first to admit that, when I was younger, I was terribly UNfit but would consider myself to be at least moderately fit now having turned my life around (hence screen name!).

Thanks again.
 
Goldfish is spot on with camera. I am supposed to be doing that as this years goals are aesthetic. Now that I am well should be logging training again soon.

Bio impedance scales rely on muscle conducting electricity more than fat, due to high water content. Theory is sound and accurate. But electricity like most things is lazy and takes the path of least resistance, up one leg across the crotch, down the other. The rest is math and assumes you have a standard body type. If you are unfit the chances are you will have just enough leg muscle to hold up your weight and walk and excess around the midriff at a disproportionately high level, even if thin. Fit ten up legs become more muscular so electricity travels faster and you should have less weight around the midsection. However the midsection is not in the path of current so this is a guess built into the scales.
If they don't have body types in it will assume a set amount of your weight is at the abdomen regardless and be less accurate the fitter and more muscular you get. They can't win.
 
You can always use the simple but very reliable measurement - tape measure. Do it once a week, say Sunday, in the morning, put the tape at belly button level (so it's the same place each time), don't drink much liquid the evening before measuring. 1-2 cm down per week is a good cutting pace.
 
Well,personally I don't think machine measurements are accurate.Better go to a physician regarding any fat %age....
 
yeah may be that't right..
 
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