Body Fat Percentage Scales
Wepz
Posts: 39 Member
Is it worth buying a decent Body Fat Percentage Scales?
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Replies
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How careful would you be using it? There largest issue with a good BIA scale is that it has to be used at close to the same hydration level to get consistent results. For example first thing in the morning (maybe after using the bathroom.), or some other time that is consistent. Additionally lean body mass is overestimated after working out, so measurements are inaccurate for a few hours after a workout.
Now if a BIA is used consistently it will at least give you a good deal of if you are losing or gaining fat. The exact number could be off a few percent but the over time the average value should be good.
There are a lot of people that claim BIA is horrible, but it probably is more in how they use the scales. I think a scale with hand and foot electrodes it going to be better than just the ones with foot electrodes.
Anyway, every method of fat measurement has pros and cons.3 -
No point wasting your money. They are so inaccurate even if you try to be consistent. The best method is go by how you look in the mirror/photos or if you want an actual measurement the scales and maybe callipers.0
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I bought one and it underestimated my body fat, IMO. Based on photo comparisons I am about 1% or so higher. But I will use my scale as a baseline to check change up or down, but I can't take it seriously.2
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They can be +/- up to 5%.0
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No. They are a joke and a waste of money. They aren't accurate and aren't really good for even guessing trends either. Here is a good synopsis IMO.
http://weightology.net/weightologyweekly/index.php/free-content/free-content/volume-1-issue-4-the-pitfalls-of-body-fat-measurement-parts-3-and-4-bod-pod-and-bioelectrical-impedance-bia/the-pitfalls-of-bodyfat-measurement-part-4-bioelectrical-impedance-bia/I've heard people make the argument that, while BIA may not be that accurate, it should work fine when tracking change over time. The theory, they say, is that the error should be the same each time you use it.
The problem is that this isn't true. As I mentioned in the article on hydrostatic weighing, the density and hydration of fat-free mass can change with weight loss. If this can affect the accuracy of hydrostatic weighing for measuring change over time, then you can be sure that the effect on BIA outcomes is going to be significantly larger.
Researchers have looked at the accuracy of BIA for tracking body fat change over time. In one study, the disagreement between BIA and the 4-compartment model ranged from -3.6% to 4.8% for measuring change. This means you could lose 3.6% body fat, but BIA would show no change. Or, BIA could tell you that you lost 8.8% body fat when you really only lost 4%. In fact, in this study, plain ol' bod mass index (BMI) did just as well as BIA for predicting change in body fat, except for in one person.2 -
3dogsrunning wrote: »
I meant that it reads 1% less bf stated than I am, not 1% off.0 -
3dogsrunning wrote: »
Sorry. It reads 1% less bf stated than I am, not 1% off.
I'm totally confused.3 -
I just bought one and use it first thing AM, but am also going to go get a body pod measurement for $50 at the local university to see what the REAL number is. Then I can use the instrument for trends (maybe). And if nothing else, a body pod measurement will help me set a good ultimate goal weight. I'm currently 200 lb.1
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3dogsrunning wrote: »3dogsrunning wrote: »
Sorry. It reads 1% less bf stated than I am, not 1% off.
I'm totally confused.
I didn't mean that the body weight scale was off by 1% only that my bf reading read 1% less than I really am.0 -
No. They are a joke and a waste of money. They aren't accurate and aren't really good for even guessing trends either. Here is a good synopsis IMO.
http://weightology.net/weightologyweekly/index.php/free-content/free-content/volume-1-issue-4-the-pitfalls-of-body-fat-measurement-parts-3-and-4-bod-pod-and-bioelectrical-impedance-bia/the-pitfalls-of-bodyfat-measurement-part-4-bioelectrical-impedance-bia/I've heard people make the argument that, while BIA may not be that accurate, it should work fine when tracking change over time. The theory, they say, is that the error should be the same each time you use it.
The problem is that this isn't true. As I mentioned in the article on hydrostatic weighing, the density and hydration of fat-free mass can change with weight loss. If this can affect the accuracy of hydrostatic weighing for measuring change over time, then you can be sure that the effect on BIA outcomes is going to be significantly larger.
Researchers have looked at the accuracy of BIA for tracking body fat change over time. In one study, the disagreement between BIA and the 4-compartment model ranged from -3.6% to 4.8% for measuring change. This means you could lose 3.6% body fat, but BIA would show no change. Or, BIA could tell you that you lost 8.8% body fat when you really only lost 4%. In fact, in this study, plain ol' bod mass index (BMI) did just as well as BIA for predicting change in body fat, except for in one person.
Very good point.
My BIA scale has had me at 27-29% bf for the past two years. In that time I have lost weight and my body composition has changed greatly due to lifting weights. I am willing to believe that I am in the 26-27% zone right now (and possibly more on an upcoming DEXA due to visceral fat) but 29% back then and virtually no change over two years? No way.0 -
3dogsrunning wrote: »3dogsrunning wrote: »
Sorry. It reads 1% less bf stated than I am, not 1% off.
I'm totally confused.
I didn't mean that the body weight scale was off by 1% only that my bf reading read 1% less than I really am.
That it would be a pretty good estimate if that is that case.
I'm also not sure how you estimate BF% by photos down to the 1%.2 -
We have the Fitbit Aria, and like it. I use the body fat readings for trending purposes only. Though the actual percentage is likely inaccurate, the trend has made sense with my 35 pound weight loss. We're planning on getting BodPod measurements in October; it will be interesting to see how they compare.0
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3dogsrunning wrote: »3dogsrunning wrote: »3dogsrunning wrote: »
Sorry. It reads 1% less bf stated than I am, not 1% off.
I'm totally confused.
I didn't mean that the body weight scale was off by 1% only that my bf reading read 1% less than I really am.
That it would be a pretty good estimate if that is that case.
I'm also not sure how you estimate BF% by photos down to the 1%.
Good point. It's close enough for me I suppose, and better than nothing. I'm going to buy some calipers to cross reference.
Here is a link for some visual bf %
https://community.myfitnesspal.com/en/discussion/261522/visual-guide-to-womens-body-fat/p6
Edited to add link0 -
3dogsrunning wrote: »3dogsrunning wrote: »3dogsrunning wrote: »
Sorry. It reads 1% less bf stated than I am, not 1% off.
I'm totally confused.
I didn't mean that the body weight scale was off by 1% only that my bf reading read 1% less than I really am.
That it would be a pretty good estimate if that is that case.
I'm also not sure how you estimate BF% by photos down to the 1%.
Good point. It's close enough for me I suppose, and better than nothing. I'm going to buy some calipers to cross reference.
Here is a link for some visual bf %
https://community.myfitnesspal.com/en/discussion/261522/visual-guide-to-womens-body-fat/p6
Edited to add link
I think where we're confused is how you're so adamant that you're BF By Photos estimation is so incredibly accurate2 -
I just bought one and use it first thing AM, but am also going to go get a body pod measurement for $50 at the local university to see what the REAL number is. Then I can use the instrument for trends (maybe). And if nothing else, a body pod measurement will help me set a good ultimate goal weight. I'm currently 200 lb.
I never paid much attention to the body fat percent on my scale having read that they are highly inaccurate. But last month I went and did the Bod Pod test and it gave me 26.8%. I rechecked the scale and it also read 26 point something, so I was surprised by that. I'd still take the info with a grain of salt, but rather keep an eye on the numbers decreasing. (hoping for 22% one of these days).
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They aren't accurate....0
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All of the posts saying "they aren't accurate" are missing the point. They don't need to be accurate. They need to be precise. Body fat measurement by bioimpedence, presuming you maintain relatively consistent conditions (similar levels of hydration at each measure) are quite precise.
They are excellent for charting progress over time, they are bad for spot measurements. I highly recommend my Omron scale which has both hand and feet sensors for body fat measurement.2 -
All of the posts saying "they aren't accurate" are missing the point. They don't need to be accurate. They need to be precise. Body fat measurement by bioimpedence, presuming you maintain relatively consistent conditions (similar levels of hydration at each measure) are quite precise.
They are excellent for charting progress over time, they are bad for spot measurements. I highly recommend my Omron scale which has both hand and feet sensors for body fat measurement.
Actually I think being consistent is important. I've found my scale to be very consistent and while that actual % BF could be off, the change seems to be tracking very well. My scale was telling me I was losing BF and when I measured my waist I was down 6 cm. I'll take that!3 -
All of the posts saying "they aren't accurate" are missing the point. They don't need to be accurate. They need to be precise. Body fat measurement by bioimpedence, presuming you maintain relatively consistent conditions (similar levels of hydration at each measure) are quite precise.
They are excellent for charting progress over time, they are bad for spot measurements. I highly recommend my Omron scale which has both hand and feet sensors for body fat measurement.
Except this isn't true. Read the article that Hornsby posted below.No. They are a joke and a waste of money. They aren't accurate and aren't really good for even guessing trends either. Here is a good synopsis IMO.
http://weightology.net/weightologyweekly/index.php/free-content/free-content/volume-1-issue-4-the-pitfalls-of-body-fat-measurement-parts-3-and-4-bod-pod-and-bioelectrical-impedance-bia/the-pitfalls-of-bodyfat-measurement-part-4-bioelectrical-impedance-bia/I've heard people make the argument that, while BIA may not be that accurate, it should work fine when tracking change over time. The theory, they say, is that the error should be the same each time you use it.
The problem is that this isn't true. As I mentioned in the article on hydrostatic weighing, the density and hydration of fat-free mass can change with weight loss. If this can affect the accuracy of hydrostatic weighing for measuring change over time, then you can be sure that the effect on BIA outcomes is going to be significantly larger.
Researchers have looked at the accuracy of BIA for tracking body fat change over time. In one study, the disagreement between BIA and the 4-compartment model ranged from -3.6% to 4.8% for measuring change. This means you could lose 3.6% body fat, but BIA would show no change. Or, BIA could tell you that you lost 8.8% body fat when you really only lost 4%. In fact, in this study, plain ol' bod mass index (BMI) did just as well as BIA for predicting change in body fat, except for in one person.
And, as I posted before, there is no way my own BIA has been close to reflecting the change in my BF% over the past two years.2 -
Respectfully, your anecdote is not a good form of evidence and is more likely related to user error than the device being off. These are well studied devices. Here are the first few papers that came up using Google Scholar, a much better free resource than some random website (Weightology).
The American Journal of Clinical Nutrition says bioimpedance scales are "sufficiently precise for use in clinical research."
http://ajcn.nutrition.org/content/64/3/489S.short
Another paper in the same journal notes that no difference was found in bioimpedance measures of body fat percent during multiple phases of the menstrual cycle.
http://ajcn.nutrition.org/content/50/5/903.short
The International Journal of Obesity estimates that bioimpedance scales have precision rates of 1.1% on same-day remeasurements, and double that for between day measurements - pretty damn good.
https://www.researchgate.net/profile/Niels_Kolthoff/publication/12743973_Validation_of_a_leg-to-leg_bioimpedance_analysis_system_in_assessing_body_composition_in_postmenopausal_women/links/55fe7bd308aeafc8ac7c5d21.pdf
The International Journal of Body Composition assessed bioimpedance precision (in rats and not people, but it's the same technology) and found its precision to be 1.5% for assessing fat mass.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2722071/
The European Journal of Clinical Nutrition also published on this question, and found that same-day retesting had a <1% variation, and multi-day retesting had a 1.7% variation when using a combined hand-foot electrode setup as many modern scales offer.
http://www.nature.com/ejcn/journal/v58/n11/abs/1601993a.html
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Wake up and measure your bodyfat using one of these scales. Now drink a litre of water and repeat. Congratulations your lean mass has increased and your bodyfat % has decreased. There is a vast amount of error in these, especially among obese and very lean people.0
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trigden1991 wrote: »Wake up and measure your bodyfat using one of these scales. Now drink a litre of water and repeat. Congratulations your lean mass has increased and your bodyfat % has decreased. There is a vast amount of error in these, especially among obese and very lean people.
This is user error, not device error.1 -
I came to this post because I'm confused about these scales and calculators and I was searching for posts about bioimoedance. The calculator link in an earlier response says I'm 27% bf, my Omron handheld says I'm 34% bf while my FitBit Aria scale says I'm 44% bf. See why I'm confused? I'm more likely to trust the Bioimpedance method than the calculated method (no scientific reason just a feeling) but I am surprised to see such a huge difference in the two similar methods. Short of paying for a DEXA scan, how do I know? I know I should just go for trending overall but the health difference between 34 and 44% is pretty significant.0
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Read the Weightology link. It explains in detail why BIA is neither accurate nor precise.0
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Thanks for recommending that. It makes sense to me now why the two BIA methods are wildy different. I am disproportional between my upper and lower body (by at least 2 clothing sizes) so the fact that the handheld estimates a much lower amount of fat as it goes through my upper body as opposed to the Fitbit scale likely only going through my lower body really does seem to explain it. I'm satisfied with just knowing this alone, and I don't need an absolute answer. I'll keep trending but at least I understand!Read the Weightology link. It explains in detail why BIA is neither accurate nor precise.
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trigden1991 wrote: »Wake up and measure your bodyfat using one of these scales. Now drink a litre of water and repeat. Congratulations your lean mass has increased and your bodyfat % has decreased. There is a vast amount of error in these, especially among obese and very lean people.
This is user error, not device error.
How is this user error? It is a method to show that hydration levels greatly affect your scale weight.0
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