Measuring body fat?

I found my set of calipers at my local grocery store in the health section. I would think just about any local health food store would have them.

The results from calipers are very likely to be dependent upon the skill of the user and the quality of the calipers. Wildly, inaccurate results are likely to occur if a) you use the calipers on yourself, b) you use cheap plastic type ones, c) an untrained person tries to take the measurement.

The only calipers that i have seen that are of a good quality to get useful results are the Harpenden metal ones. These retail (last time i checked a couple of years ago), for ~ UK£250. I'm certain there would be other reputable metal calipers available as well.

I've never seen the Jaycar bf% scales that you mention, so can't comment on thier accuracy. Some of the BIA scales are quite accurate -- however, their use is that they require no skill on the part of the operator (just that the subject is always hydrated to the same levels etc).

Ric

the best BIA scales are made by Tanita and you should be able to find info and dealers on the net.

in general BIA is fairly accurate although it underestimates fat in obese people and over estimates fat in very lean people.

also as Ric said make sure you take the measurement under the same conditions each time for example just after getting out of bed.

unless you use very expensive methods of testing bodyfat like DEXA or underwater weighing measuring bodyfat at home will rarely give you an exact result and is mainly useful for determining if you are gaining or losing fat from week to week

Are those body-fat scales really sensitive enough to monitor fat composition levels week-by-week? The Jaycar site says it's accurate to +/- 0.5%. How quickly does body fat percentage generally change over time?

I've sometimes thought about buying one to use as a relative indicator of my fat levels, i.e. not taking its body fat % reading as gospel, but something to track changes (hopefully decreases 🙂 ) in body fat over time. Kind of like how I (and some others) use the Polar OwnIndex score; sure, it isn't an exact match for VO2max, but at least when it rises, it's a good indication you're getting fitter.

(Edit: a bit of googling around shows there are some Tanita body fat scales that are accurate to 0.1%, for about US$90.)

Quoted post said:

Originally posted by rek
Are those body-fat scales really sensitive enough to monitor fat composition levels week-by-week? The Jaycar site says it's accurate to +/- 0.5%. How quickly does body fat percentage generally change over time?

I've sometimes thought about buying one to use as a relative indicator of my fat levels, i.e. not taking its body fat % reading as gospel, but something to track changes (hopefully decreases 🙂 ) in body fat over time. Kind of like how I (and some others) use the Polar OwnIndex score; sure, it isn't an exact match for VO2max, but at least when it rises, it's a good indication you're getting fitter.

(Edit: a bit of googling around shows there are some Tanita body fat scales that are accurate to 0.1%, for about US$90.)

I don't know what the accuracy level refers to (i.e., +/- 0.5% compared to what??). It certainly *won't* mean absolute levels as even the 'gold' standard (hydrostatic weighing) isn't that accurate. Body fat % measurements have been compared between various methods, and the only truly accurate (although completely useless method) is to have all your fat weighed and then calculated as a % of total weight. Of course the only way to have all your body fat weighed is to have it cut off you (i.e., you're dead!). The actual difference between hydrostatic weighing and actual body fat weighing was in some individuals quite alarmingly different.

Ric

Ric,

Thanks for your comments. I presume the "accuracy" is referring to the increments in reporting body fat percentage, i.e. 0.5 would mean it'd go 20.0->19.5->19.0% as you get fitter or something.

I'm not so interested in using one of these scales as an absolute measure of body fat percentage, but more something as an aid to track decreasing body fat over time (i.e. looking at the downward trend of measured body fat %, rather than looking at singular results in isolation.)

Would one of these impedance-based fat scales be useful for such a purpose, or would the results it give be too inaccurate/unreliable/variable?

It sounds to me that it's a little optimistic to expect it to reliably (and repeatedly) give accurate results from such a measuring system. And if the measurement equipment is giving wildly different results from one week to another, there isn't much point in using it in the first place.

Rek,

To be brutally honest -- i'm not sure how useful the BIA systems are. Caveat; i've never used one or tested it to a known standard (e.g., hydrostatic weighing) -- so from a practical viewpoint i'm just not sure how good (or not) they are.

I do know you need to keep conditions very similar, and they obviously require no skill on the operators part (unlike calipers).

2Lap who is also a sports scientist (i think) may have an answer, and if not i've got some colleagues who've used them (although not necessarily the models you mentioned).

Ric

Well, I could make myself a guinea pig, and let you know how it all goes...unless someone else can save me the trouble?

i'd have to ask why you need to know your bodyfat percentage, sure its nice to know but its not a quantitative measure of sports performance unless you are a bodybuilder.

generally you should be able to tell if you are lean enough by looking in a mirror

Quoted post said:

Originally posted by Duckwah
i'd have to ask why you need to know your bodyfat percentage, sure its nice to know but its not a quantitative measure of sports performance unless you are a bodybuilder.

generally you should be able to tell if you are lean enough by looking in a mirror

I agree and your belt tells you if your body fat % is going up or down 😄

I have a set of tanita scales. The % fat readings are fairly consitent and mine have been going down by about 1% since I got it (was 16, now 14%). A far cry from the 9% I was in my hey day.

I have a set of Tanita scales. In terms of accuracy, they are reasonably stable from one week to the next: I use them every Saturday morning and get a very consistent answer: I've been at 17.0% for each of the last 6 weeks (according to the scales). I've monitored my fat over time using them and seen the fall from 22%. As to whether I'm actually at 17 though, I'm not sure, I reckon I'm closer to 12%...

However, I would question the basis of calculation. You have to enter your gender, height and whether you are child or adult. It then weighs you, before calculating your fat. I wondered if it was using this data to estimate what it thought I should be in relation to norms, so to test it I put a ruck sack on my back full of books. Hey presto, I'd put on 15Kg, but guess what, apparently it was mostly fat (I think it was showing me as having gone up from 17% to around 24%). Maybe it's the type of books I read...

Quoted post said:

Originally posted by steve
I agree and your belt tells you if your body fat % is going up or down 😄

Have to agree with you Steve, that and tight trousers. 5th hole on the belt - happy(ish), 5-4 - perturbed, 4 - oh s... better put the miles on or give up the booze. It's bloody hard work being middle aged!

Quoted post said:

Originally posted by ltsop
Anyone know where I can get a set of body fat calipers or similar to measure my body fat %? I've asked around in sports stores, chemists, etc. but no go. The only product I've found on the web in Australia is a set of body fat scales from Jaycar (http://www1.jaycar.com.au/productView.asp?ID=QM7249&CATID=&keywords=body+fat&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=xxxxxxxxxx&Keyword2=xxxxxxxxxx&pageNumber=&priceMin=&priceMax=&SUBCATID=)

(anyone tried these?)

Thanks

Here's 3 methods you can use that are free.

1) Can you see abs, including lower abdominals - if so you are ripped - don't worry about it.

2) Stand in front of a mirror and tense your muscles -jump up pretty muich whatever wobbles is fat - get rid of it.

3) Are you happy with yourself naked?

basically modify diet and training until you are happy with number 1,2 or 3.

If you are looking for a good site with more info then I really suggest www.t-mag.com . It's strength training focussed but a lot of really good current stuff on nutrition, training, supplements, drugs etc.

Other than that I have used the fatrack II bf caliper but it's only 3 points and not really accurate - at $39 AUS it's okay.

I also have a Tantia BF scale and it's okay too as an indication of an overall trend.

But really the mirror has got to be the best way to tell - if you look good and lean you are. If you are don't look good it's time to start keeping a food and training log.