banerjek

My wife has one of those scales that measures body fat as well as weight. I realize that they are not accurate, but I'm wondering how accurate they are?

In the 3 years she's had the thing, my body fat level consistently hovers around 13.8% according to this gizmo. However, I'm thin as a rail and my weight is typically a tick below 140. I'm 5'10", have no paunch, etc. I probably ride around 10,000 miles/yr and I would be considered a very active person even if I didn't cycle at all. My lifestyle has not changed for many years.

I keep hearing about people with significantly lower percentages of body fat than I do and was wondering if I really have as much on me as the scale suggests. I've actually been trying to gain weight for years -- I eat large portions and snack throughout the day (all healthy stuff) to maintain my weight. I'm not interested in losing weight even if I am carrying fat -- family and friends already think I am too thin -- but I was just wondering if I really have that much on me?

BikingCT

Terribly inaccurate, IMO.

We have a scale version as well. It consistently shows my BF as being 10% higher than on the hand-held electronic versions, which are consistently 5-7% higher than the good old-fashioned calipers. Which do I believe? I like the calipers because they are the lowest (currently at 18%)!!

Now, the scale might be a bit goofy because of my size (6'3", 250 lbs), but they are supposed to account for that. Also (not to sound gross), if you use the scale to test your BF, use the toliet, and test again, the BF number can change by a percent or two. I use the BF scale to only monitor long-term trends.

*new*guy

If you belong to a gym, you should be able to get a 7 site test for free. If you have someone who can do the test for you, buy your own calipers. The subscapular measurement is pretty hard to do yourself

umd

I just got one of the Tanita Ironman scales. I can't say how accurate it is, but it seems reasonable if a bit under reported for me. It told me 5%, which does seem a bit low but I'm 5'10" 128lbs. I've been also working out at the gym a lot for my upper body so I am fairly muscular (as much as you could expect for weighing so little!). I know that I don't always drink as much water as I should and that definately affects the results.

For my wife the reading is way higher than it could possibly be. But she also drinks TONS of water (actually I wish it was water, but she guzzles Perrier ). We both plan on getting a hydrostatic test done so that we have a better frame of reference.

edit: a little while ago after I hadn't been at the gym for a few months I had the caliper test done and came in at I think 15%. Since then I've lost about 8 pounds and build back up my upper body, so less weight and more muscle, 5% could be just about right. I haven't had the test redone.

superdex

I have a Tanita as well that I've been using for about a year, and for tracking relative changes, it's worked out well. There is an 'athlete' setting, though there is no help for a) determining when you switch over to it or b) how it changes the readings. I've watched my body fat % go from 19% to a low of 14.9; today it was 15.5%. Over the same time, I've gone from 215ish to a low of 194 and change. Today, at 196, I'm happy. (I'm 6'3")

Checking it at the same time every day makes a HUGE difference. I do the 'morning pee then weigh' method. Is it accurate? I don't know, I haven' had my bf checked any other way. Do I care? Not really, because I've been able to track my progress. (fwiw)

spunky

5'10" and 128lbs.......?
Jeebus!
I wouldn't be surprised if you're at 5%.
I'm about 5'8" 142lbs and according to the handhelds I come in around 5-7% usually which is probably off.
People are always telling me how I need to eat more.
I bet it's much the same for you.

jrennie

I was tested at my last physical by the doc at 4%
On the tanita scale in normal mode 13%
in the athlete mode 3.8% I would guess they are fairly close but what time of day it was and how much water I had to drink would sway it a couple of %

5'11" 140lbs

umd

Yes, people do tell me that I need to eat more.

bonutz

I was just reading this little blurb on a website about measuring bodyfar:

Using Home Body Fat Scales to Measure Body Fat

Body fat scales claim to measure body fat quickly and conveniently. These body fat scales use the Bioelectrical Impedance method to measure your body fat percentage. A low-level electrical current is passed through your body and the "impedance", or opposition to the flow of current, is measured. The result is used in conjunction with your weight and other factors to determine your body fat percentage. Unfortunately, your body's "impedance level" can be altered by many factors besides body fat. For instance, the amount of water in your body, your skin temperature and recent physical activity can all adversely affect the results.So only by following strict rules can you hope to get an accurate measurement of your body fat using these scales. The most important rules to observe in order to make a more accurate calculation of your body fat are:

* Don't eat or drink for 4 hours before the body fat measurement test.
* Don't exercise for 12 hours before the test.

Notes:

* Some studies have shown variances as high as 8 percent when using the bioelectrical impedance method even if the rules are precisely followed.

OPC

My Tanita scale literature indicates the main difference between 'non-athlete' and 'athlete' as someone who regularly exercises 10hr or more per week. I do not know how this affects the calculation, but my BF% is certainly lower in the 'athlete' mode.

Still, I use it as you do - to track long term trends.

-José

mx_599

hit and miss.

you could be in the low teens

mx_599

yeah...get some Lange calipers...about 230 bucks

mx_599

years ago, all the femalles in my class were pissy about their measured BF. females are often higher than what you might expect, maybe yours is okay

supcom

Generally electronic bodyfat scales used by consumers do not have a real high accuracy. The main factor limiting the accuracy, as I recall, is your hydration level. If you test yourself throughout the day, you will probably find your BF% is highest in the morning when you first wake up (dehydrated) and your lowest later in the day after you have consumed plenty of fluid.

The best way to use these scales is to pick a time of day when you feel you are probably at a fairly constant level of hydration. I like to test when I first come home from work (before exercise!). Do not be too concerned about the absolute value. Average the data over several days or a week and look for trends. You will find that your BF% can swing a percent or more on a day to day basis, so averaging is best.