Inaccurate body fat measurement

fivelongmiles · January 2015

Now, I know most ways of measuring are fairly inaccurate, but bear with me.

If you look at one of those images that shows you what the different percentages look like, I look like 20%. I've been 15% before and that's my goal again. The machine in Boots, which I know isn't the height of accuracy but has always been almost spot-on with me, agrees that I'm 20%.

However, I have a new personal trainer and he used the little handheld thing at the gym today and it said 27%. That's not an issue for me, because I know it's completely wrong, but I'd told him my goal was 15% and he'll think we have a much longer way to go than we actually do - by my reckoning, 5 or 6lbs will get me looking how I want but he'll be assuming at least double that. I'm not quite sure how to discuss this with him without sounding like a know-it-all. Is there a nice way to say "your machine is nonsense" without sounding horrible?

The reason I ask is because a few years ago I'd been training in my sport full time, taken a few months out but stayed in good enough shape, and when I joined a gym to help ease back into it the guy there was insistent that my body fat percentage was 30% according to his machine and put me on some fat loss programme even though you could see my abs enough to count at least 4 of them. He wouldn't listen then, perhaps assuming he knew more than me, and wouldn't help me with other machines that I'd have preferred to use so I could have a plan more suited to my needs. I don't want to end up in that position again! I'd like to make sure I have the plan I need (shift a couple of pounds but mostly get stronger and rehab old injuries) rather than the plan someone thinks I need based on a nonsense measurement.

(Before anyone asks, no, I didn't see the 30% guy again - I was paying enough to be at that gym without paying more to do nothing! Sadly, though, he was always the only one on duty at the times I could fit a workout in around work and he wouldn't teach me any of the other machines, so I drifted away and didn't renew my membership.)

usmcmp · January 2015

Tell him that bioelectrical impedence is highly inaccurate. That you can use it after going to the bathroom then use it again after drinking 32 ounces of water and your body fat will change by up to 5%.

Now, was that your only question because I didn't really see another question in there. I think you could probably just ignore the machine and just go by what you see in the mirror and how much you like what you see. Body fat percent doesn't matter if you don't like how you look.

edf620 · January 2015

So I'm interested in getting to a 17% bf to meet proper racing weight. I wrote a training facility near me to see if they'd test my bf. Here is their response "In regards to the testing you’re looking for, we can definitely do body fat %. This is performed using skin-fold measurements by calipers, which are then inputted into an equation to find out your BF %. This is considered the standard protocol and is much more reliable than current impedance, or handheld devices. The best is BodPod testing and Underwater weighing, both of which are extremely rare to find. "

Maybe try a caliper method of checking?

tulips_and_tea · January 2015

What is the sport you mention that you are training for? I ask because I'm wondering if there are coaches or trainers available specific to your sport that may be more helpful to you.

Sometimes you have to try several personal trainers until you find one you mesh with. And, if body fat % is important to you maybe pay once to have one of the more accurate (and expensive) ones done? I'd like to just out of curiosity for myself, but don't really want to spend the money right now.

fivelongmiles · January 2015

usmcmp wrote: »

Tell him that bioelectrical impedence is highly inaccurate. That you can use it after going to the bathroom then use it again after drinking 32 ounces of water and your body fat will change by up to 5%.

Yeah, that was my only question. That's basically what I told the last guy and he wasn't happy, so I was just wondering if there was some way I could explain it without sounding like a bit of a spoon.

edf620 wrote: »

Maybe try a caliper method of checking?

BZAH10 wrote: »

What is the sport you mention that you are training for? I ask because I'm wondering if there are coaches or trainers available specific to your sport that may be more helpful to you.

Sometimes you have to try several personal trainers until you find one you mesh with. And, if body fat % is important to you maybe pay once to have one of the more accurate (and expensive) ones done? I'd like to just out of curiosity for myself, but don't really want to spend the money right now.

I was a dancer, but my sport at the moment is gymnastics. I'm attempting something that's never been done before and I really need to be a machine to do it!

I'm not too worried about the actual number - not enough to go to the effort of finding somewhere to get it tested properly - but thank you for the suggestion! Body fat was one of my main goals when I started with this trainer, along with bodyweight strength, so it's going to be one of the things he's helping with and I want him to really understand that I'm only around 5lbs away from my goal, not 14+, so that he can plan ahead to us completely changing things up in a short while and not months ahead.

Thanks, everyone. I'm probably worrying too much because he's been nice enough so far, but I think I'm still hung up on how much of an issue that last trainer made of his big fancy machine being "inaccurate". I wish I'd had that chart with the photos back then, I'd have brought it in so we could compare me to the chart!

Francl27 · January 2015

I sympathize, I had the same problem at my gym. Now I'm not even having my bodyfat measured anymore because I don't see the point.

usmcmp · January 2015

turkfox wrote: »

usmcmp wrote: »

Tell him that bioelectrical impedence is highly inaccurate. That you can use it after going to the bathroom then use it again after drinking 32 ounces of water and your body fat will change by up to 5%.

Yeah, that was my only question. That's basically what I told the last guy and he wasn't happy, so I was just wondering if there was some way I could explain it without sounding like a bit of a spoon.

edf620 wrote: »

Maybe try a caliper method of checking?

BZAH10 wrote: »

What is the sport you mention that you are training for? I ask because I'm wondering if there are coaches or trainers available specific to your sport that may be more helpful to you.

Sometimes you have to try several personal trainers until you find one you mesh with. And, if body fat % is important to you maybe pay once to have one of the more accurate (and expensive) ones done? I'd like to just out of curiosity for myself, but don't really want to spend the money right now.

I was a dancer, but my sport at the moment is gymnastics. I'm attempting something that's never been done before and I really need to be a machine to do it!

I'm not too worried about the actual number - not enough to go to the effort of finding somewhere to get it tested properly - but thank you for the suggestion! Body fat was one of my main goals when I started with this trainer, along with bodyweight strength, so it's going to be one of the things he's helping with and I want him to really understand that I'm only around 5lbs away from my goal, not 14+, so that he can plan ahead to us completely changing things up in a short while and not months ahead.

Thanks, everyone. I'm probably worrying too much because he's been nice enough so far, but I think I'm still hung up on how much of an issue that last trainer made of his big fancy machine being "inaccurate". I wish I'd had that chart with the photos back then, I'd have brought it in so we could compare me to the chart!

Next time just challenge him to take his then drink a bunch of water. It's all the proof you need. Either way he showed he probably wasn't the trainer for you.

Inaccurate body fat measurement

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