43% body fat. What the hell?
February 26, 2011 11:38 AM   Subscribe

43% body fat. Am I about to drop dead, or is my scale wrong?

I am 5'5, 159 pounds (72 kilos). I am in my mid 20s and female. I am fairly active: I bike and/or run for an hour or more 5 times a week, walk everywhere, etc.

I recently bought an Omron scale which calculates body fat %, visceral fal, and weight. My visceral fat is 6, which is apparently within normal range. But my body fat % calculated at 43% - this seems, to me, to be an extremely high number.

I'm scratching my head here - can I be that unhealthy, despite being very average body shape wise? What gives, hivemind? Should I worry?
posted by Sijeka to Health & Fitness (19 answers total) 2 users marked this as a favorite
Doh! 'I am in my mid' = 'I am'!
posted by Sijeka at 11:39 AM on February 26, 2011

Those scales are notoriously inaccurate, especially if you are athletic. If you're really worried about your BF% find someone who is experienced with calipers or a place that will do a water displacement test.
posted by elsietheeel at 11:40 AM on February 26, 2011

Calculating bodyfat is a very inaccurate science, and there is no way to determine actual bodyfat. At best, it's a calculated guess. The most accurate way that medical centers determine it is by placing the patient is a pool of water and seeing how long they float. From there a formula can be used to determine what the bodyfat is estimated to be.

These scales are very inaccurate and use a modified BMI formula to determine these. I would be highly skeptical of these, and are mostly a marketing gimic. Bodybuilders who are usually overweight due to muscle have very high bodyfats according to these scales where as a caliber or other more traditional way show a more accurate fat. I would not rely on these, but if you are worried; contact a fitness center or find someone with a body fat caliper. They will give you a better ballpark range of bodyfat then one of these scales.
posted by lpcxa0 at 11:43 AM on February 26, 2011

Those devices are just bollocks, to be honest. They have a lot of built in assumptions about your anatomy and composition that can be quite wrong.

Example: my father-in-law doltishly gave my beloved a handheld device that works on this principle. I tried it, and it showed me as ~30% bf at a time when by calipers, tape measure and visual assessment I was 15%.

Get calipers for a more believable measurement and treat this device as a relative measure only. Ie, if there's a downward trend, your body composition IS improving, but the actual numbers are nonsense.
posted by i_am_joe's_spleen at 11:47 AM on February 26, 2011

If you'd like to get a single but very accurate body fat reading, look for a place near you that offers hydrostatic weighing. Your best bets for this would be university departments or sports health centers, or inquire with gyms with pools to see if they have anyone periodically come to offer it. It'll give you a good one-time measurement, and then go with i_a_j_s' recommendation about using the scale's measurements as a relative measure.
posted by WCityMike at 11:50 AM on February 26, 2011

As it says in the OP's link, the scale measures bodyfat via bioelectrical impedance analysis. This has nothing to do with BMI, and being "overweight" due to muscle mass should not affect the measurement. These scales are known to be inaccurate, though. Mine seems to overestimate by 5-8%. Try measuring yourself at different times of day and see how much the measurement fluctuates.

All that said, it's not impossible for you to be overfat based on your description. A visual assessment would make it pretty easy to tell if you were actually close to 43% bodyfat.

In addition to the water tank method, DEXA scans are considered more accurate means of assessing bodyfat.
posted by Anatoly Pisarenko at 11:55 AM on February 26, 2011 [1 favorite]

How about taking this approach: inside each of us is a body at its ideal weight. Then we bolt all this muscle and fat on top of that.

If you are a female in her 20s at 5'5, then inside you is a body which weighs 125 pounds. That body is composed of about 20% fat, which means that 25 of those 125 pounds are fat.

Now if you told me that you weigh 250 pounds (twice that) and that the scale told you that you're half fat, I would believe it as plausible.

But if you weigh 159 pounds, then you've only added 34 pounds of material (either muscle or fat) to that ideal frame. 25 + 34 = 59 pounds of fat.

59 pounds of fat would still put you at only 26% body fat.

I'm not saying it's impossible to be half made of fat at 159 pounds and 5'5. I'm just saying it's scientifically and mathematically unlikely.

It's much more plausible that, as everyone else has mentioned, the scale's measurements are kinda crappy and inaccurate.
posted by ErikaB at 12:20 PM on February 26, 2011 [4 favorites]

59 pounds of fat on a 159 pound person is 37%, not 26%.

Not that those scales aren't garbage, I'm just pedantic like that.
posted by RustyBrooks at 12:24 PM on February 26, 2011

How about taking this approach: inside each of us is a body at its ideal weight. Then we bolt all this muscle and fat on top of that.

If you are a female in her 20s at 5'5, then inside you is a body which weighs 125 pounds. That body is composed of about 20% fat, which means that 25 of those 125 pounds are fat.

With all due respect, this is total bunk. There is no single "ideal weight." There's a large range of weights at which a 5'5" woman could be healthy and fit, both lighter and heavier than 125 pounds. And the idea that adding muscular bodyweight is bad because it takes you further from some "ideal weight" is nonsense as well.

Generally speaking, a healthy bodyfat range for a woman is anywhere from 14% to 29%. What that translates to in terms of scale weight is variable dependent on the size of her frame and amount of muscle mass.
posted by Anatoly Pisarenko at 12:28 PM on February 26, 2011 [5 favorites]

Here's a visual guide. My stats are similar to yours and the visual guide places me between 25 and 30%, while a bioelectrical-impedance scale consistently yields 38-40%. As others have suggested, you could use the trend as a guide instead of the absolute number.
posted by ecsh at 12:28 PM on February 26, 2011

Thank you all so much for your answers so far. esch, I would be between the 25 and 30% image myself, I guess (but I wear the fat in my butt/thighs as opposed to my stomach, which is fairly flat).

I shall take the readings with a pinch of salt... but now, if they were to be accurate with a relatively liberal margin of error -- how unhealthy/dangerous is it to have a high body fat %, as opposed to visceral fat, if one is nonetheless physically active and eats well, I wonder?
posted by Sijeka at 12:37 PM on February 26, 2011

Take the readings with a huge grain of salt. You're probably nowhere near 43%, and most likely in the 20-some-odd percentile. If you really want to find out what your bodyfat is try calling up the local university's health department, and ask if they can test you. If they use calipers (which is fine) ask how many sites they pinch and if it's only three then don't waste your time, it should be more like 9 or 12. Also if that person has worked with enough people they can probably uncannily tell you what your bodyfat is just by looking at you.
posted by P.o.B. at 2:52 PM on February 26, 2011

Along with all the above, I was learning just today about how essential your level of hydration is with those scales. Try hydrating for several days and see if you get a more accurate answer.
posted by ldthomps at 2:56 PM on February 26, 2011

(sorry, that was answering your second question)
posted by unknowncommand at 4:21 PM on February 26, 2011 [1 favorite]

Just as a data point, when I was at my absolute fittest, I was having my body fat tested somewhat regularly. My low was 16% measured in 7 spots with calipers, and 18% measured hydrostatically. I hopped on my brother's bodyfat scale just out of curiosity and it said 28%. It just my belief that those scales are not only "inaccurate" but are flat out scams. I think they use averages or something.
posted by peep at 4:31 PM on February 26, 2011

As another data point, I have two scales, each of which supposedly measures body fat. One puts me at around 34%; the other at around 24%. I am extremely fit, and have a BMI of around 21. Nevertheless I believe that either of those body fat measurements is possible. Women are meant to have high body fat, and find it very hard to reduce.

Short answer: body fat measures on a scale are wildly inaccurate, but a fit healthy woman can have quite a high body fat percentage without it being visually obvious.
posted by lollusc at 5:40 PM on February 26, 2011

You can use a different metric as a second opinion. Read up on body mass index.
There are a lot of resources online that calculate your BMI and help you decide whether you want to talk to a dietician or doctor.
I used an online BMI caculator from the Dutch government with the numbers you gave which resulted in a BMI of 26.4.
BMI isn't an exact science but can be used as an indication whether this is worth talking to your doctor about. Mostly because it doesn't take into account how your body type differs from the mean.
It seems that your maximum healthy weight is 5 kg lower. And your 'ideal weight' is 15 kg lower.

Back to your question "should I worry?": I'd say talk to your GP about it next time you see him.
posted by joost de vries at 1:01 PM on February 27, 2011

I'm assuming the scale you're using is the type that has the metal footplates, and estimates body fat from electrical conductivity measurements? My scale of that type tells me (5'9, 150lbs = 23 or so BMI by the numbers, right in the middle of "healthy weight" on the range) that my body fat percent is either 26% or 33% (mid "overweight" to low "obese" BMI values, I'd have to weigh >200lbs to have the calculation come out like that). I forget whether it says 26% when my feet dry and 33% when they're are moist after a shower, or the other way around, but yes, my "body fat" changes by 7 points every morning while I'm in the shower.

I've stopped using that feature of the scale, it's total rubbish.
posted by aimedwander at 8:03 AM on February 28, 2011

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