Electric Impedence Bodyfat Testers

[Viking Dan]

Anyone used one? The stuff I've read on them seems to conflict on how accurate they are.

[Ottawa]

I find the one that I use accurate if used at the time every day and before eating. My wife got this one for me at 75 lbs. lost, and I use it about once a week first thing in the morning. I know that BF% is slow to change and a week should not make much difference but it is just another "scale" of sorts and we have to face up to our addictions.;)

You can do several readings in a row with less than .2% variance yet have breakfast and come back and it is up 1.5%. Day to day it does not vary much unless eating in the evening or if I do a strength workout in the the night before I will notice that it is up almost a half percent.

Using the Navy Method calculations for body fat shows .5% to 1% higher than the BF calculator but that could be my specific body composition.

It is a fun tool at get togethers if your friends art competative but it is a chore entering their data (age, weight, sex, height) to get the readings when a bunch of people are competing for "better numbers".

[Mitra]

I have one. The readings vary throughout the day, so getting consistent results does depend on following the directions about when to weigh, and keeping conditions constant. The readings agree with the Protein Power calculation within a % or two, and have done so throughout my weight loss (ie from about 35% to about 20%).

[Viking Dan]

Are you using a handheld model, or is this built into your scale?

[Ottawa]

Are you using a handheld model, or is this built into your scale?

Mine is a handheld model and I keep it near my computer which is why I use it a little more often than I should. I don't have the model handy but it came from radio shack and I think that they all work using the method, electrical resistance correlated with age, sex, etc..

[Mitra]

Mine is built into the scale.

[banshee]

I got a scale that included the body fat tester when I was halfway through my weight loss. I've never been happy with it. It always tests me at about 10-15% higher than the Navy calculations. Maybe it's right and the calculations are wrong, but that doesn't mean I have to like it! :rolleyes:

Of course, if it is right, that means that when I started my journey, I was at 65-70% body fat instead of 55%! :eek:

I may try it again after 6 months of strength exercising and see if it seems closer to what I think it should be... but someone once told me that if you are very short or very tall they don't work right. Since I definitely fall into the very short category, that may be why it seems off for me. (This may be just for the scale-based ones that require the current to go through your feet. I have no idea how the handheld ones are supposed to work...)

[Mitra]

I'd be surprised if it was just height - if it's one, like mine, where you have to tell it your height. I'm only 5' 2", and get pretty good agreement with the calcs.

I think you've said before that more of your fat is stored in your lower body, so it may be that for your body shape it gives an artificially high reading.

[Ottawa]

Mary,
Are you required to enter your own data in th eunit or just step on it?

I think that we all have diffentent body compositions yet a common base. My legs are likely my strongest muscles and much of that came from years of carrying over 100 excess pounds everywhere that I went. I have seen other men with incredible torsos yet almost no lower body development and I'm sure it would show errors using BF Calculators since the current takes the path of least resistance (muscle and some fluids) and has teh most effect closer to teh point of contact.

[banshee]

I'd be surprised if it was just height - if it's one, like mine, where you have to tell it your height. I'm only 5' 2", and get pretty good agreement with the calcs.

I think you've said before that more of your fat is stored in your lower body, so it may be that for your body shape it gives an artificially high reading.
I do input sex and height. But if as Ottawa says,

the current takes the path of least resistance (muscle and some fluids) and has the most effect closer to the point of contact.
then I can see where with more lower body fat, the scale might be doing as you say and giving an artificially high reading because it's finding an "easy" path along just the lower body or something. I don't claim to understand how these things work, I just know that when I use it the reading seems way off. Now as I said before, I think the calculators might be off a bit, too, but I don't think they're off 10-15% or I wouldn't be fitting into size 8-10 pants! If it was only a 5% diff, I might say the scale was more accurate.

Anyway, since I mostly go by clothes and tape measurements anyway, it doesn't really bother me. I just wanted to put my two cents in because Dan was asking about the accuracy.

What kills me is that *none* of the methods typically used seems to be totally reliable. Calipers vary in accuracy depending on the skill of the user, tape measurements/calculators can be off if body shape stores fat in places not measured, and the electrical impedence method seems to have its own problems, including having trouble with athletes that have a low body fat percentage from what I've heard. I've even heard that the body immersion in water test, which I had always thought was the most accurate, has shown to be innaccurate if not performed correctly. You'd think the fitness community/businesses would be able to come up with *something* that is guaranteed accurate no matter who uses it, what body type they have, etc.! :mad:

[Viking Dan]

IYou'd think the fitness community/businesses would be able to come up with *something* that is guaranteed accurate no matter who uses it, what body type they have, etc.! :mad:
Other than dissection? :p

[banshee]

Other than dissection? :p

Yes, Dan, other than dissection! :D

[LisaS]

I saw an episode of FitNation on FitTV. the topic was obesity and fatness in general.

The host took a subject (male, athletic) to all sorts of pros for BF measurement - calipers, digital calipers, tape measure+formula, bod pod, underwater weighing, impedence (2 kinds I think, the gripper kind and the multiple electrode (including ankles) kind) -- the upshot that I noticed was that the results varied really widely for this single subject (I seem to remember a 7% swing but could be wrong) --

but the results using any one method over time were thought to be consistant - if hydration levels were also kept consistant. so thoughtful use of calipers by same person, meticulously at the same places (measured from anatomical landmarks) with appropriate algorithms would show consistant trends, as would tape measure (same caveats) or bod pod or underwater weighing.

[banshee]

I saw an episode of FitNation on FitTV. the topic was obesity and fatness in general.

but the results using any one method over time were thought to be consistant - if hydration levels were also kept consistant. so thoughtful use of calipers by same person, meticulously at the same places (measured from anatomical landmarks) with appropriate algorithms would show consistant trends, as would tape measure (same caveats) or bod pod or underwater weighing.

Yep, that's what I generally use my measurements for - to show the trend over time. I know that I've lost about 28% of my body fat since I started PP. It's just now when I'm trying to lose the last of it that knowing my exact BF would be useful - i.e., how close to the "healthy" 20-25% I really am, versus how close I think I am.

[Viking Dan]

I'm not really concerned with accuracy as long as its consistently inaccurate.

The navy method puts me at 19ish, while the calipers suggest 23. I'm inclined to side with the calipers, but I need a 3rd method to make me more insane, so we'll see what the elctrocuter says.

[banshee]

Well, as far as consistency is concerned, the scale was pretty much always 10-15% over the measurement method. (And I'm not saying that sometimes it was 10 and sometimes it was 15 - I just can't remember if it was 10 or 15...)

So if you don't mind consistently inaccurate, the scale should work fine for you. :p

[Viking Dan]

So if you don't mind consistently inaccurate, the scale should work fine for you. :p

Nah. The scale has some bizarre tendancy to think I'm a pound or 2 lighter after a shower. I can't accumulate that much dirt in a day; can I?

[Viking Dan]

Okie dokie. I got an Omron unit (http://www.amazon.com/gp/product/B0001VRL0A/103-7474154-5183052?v=glance&n=284507) for $30 or so off eBay. I like it in that I can't cheat with it as I can with a tape measure(i.e., picking favorable angles or pulling it so taut my intestines blow out my ears like macabre party streamers.)

I dislike it in that it registers a good 5-6% higher than the other methods I was using. Seems to be consistent(with itself) within a fraction of a percent. The more contact I make with my palms and the electrodes, the better it seems.

Ah well. Just further motivation I suppose.

[Ottawa]

Mine is an Omron as well. Although it does register a little higher than the Navy Calculation method I think that error may be increased as you develop more muscle mass, especially if you were overweight before. I have a large build (chest, hands, etc) and I think the erro is introduced with different body types as pointed out earlier.

I believe the unit is a resistance measurer that applies the data to a lookup table, based on your input values. The lookup table would be based on averages and if outside that range you get more error.

That said, it is a handy reference tool over time.

[Viking Dan]

I have a large build (chest, hands, etc) and I think the erro is introduced with different body types as pointed out earlier.
Me, too. Much like insurance company height/weight tables, the device's flaw is that its calibrated for humans as opposed to apes. :p

[mcsblues]

I have a Tanita scale with BIA built in and I just don't use it at all! It is neither accurate or consistent in my experience, even following the directions to the letter. Some clinics have professional BIA machines which are supposed to be a lot better (they supposedly take hydration into account for example) but IMHO for home testing a simple set of skin fold calipers are probably the best.

[gator8me]

I am wondering how the fact that we eat more fat in our diet affects the readings? Or would that be taken care of if you consistantly measured body fat in the morning BEFORE eating or drinking anything?

I am curious because i'll be getting mine measured this week.

[Viking Dan]

Apparently the contents of your stomach can influence it.

Being underhydrated can cause you to register as fatter on these things.

[gator8me]

so keeping hydrated (not a problem for me lol) and doing it BEFORE eating in the morning should help keep it most accurate you think?

[Viking Dan]

Doing it at the same time of day under the same conditions should keep it consistently innacurate. ;)

Blues does have a point. Skinfold calipers are probably more consistent, but they don't have as many blinking lights. :p

[gator8me]

lol and i'm such a blinking light, button pushing, electronics type person! lol After I move I will most likely invest in one of my own. Can't believe you found one that nicely priced even on Ebay! Who did you buy from?

[Viking Dan]

http://search-desc.ebay.com/search/search.dll?sofocus=unknown&sbrftog=1&fcl=3&from=R10&amp%3Bsspagename=h%3Ah%3Aadvsearch%3AUS&catref=C5&nojspr=y&frpp=50&satitle=omron+hbf+306&sacat=-1%26catref%3DC6&bs=Search&fts=2&fsop=1%26fsoo%3D1&coaction=compare&copagenum=1&coentrypage=search&sargn=-1%26saslc%3D2&sadis=200&fpos=ZIP%2FPostal&ftrt=1&ftrv=1&saprclo=&saprchi=

Not sure atm. I went with the Omron because it had the best reviews on Amazon.