Talk:Body fat percentage
|WikiProject Medicine||(Rated C-class, Mid-importance)|
Are Americans really obese on average?
The table suggests that 25% (32%) body fat for men (women) is considered obesity. The graph by the national nutrition survey of body fat percentage for different genders and age groups suggests that on the average, Americans are obese at all age groups. Does this make sense? Seems a bit drastric. — Preceding unsigned comment added by Matanbz (talk • contribs) 05:24, 19 January 2019 (UTC)
I don't it is too drastic to say this. It's very common, just look at this article about a town in Australia. Australia's obesity epidemic bites in Katherine, which data shows is among the nation's heaviest, where over 33% of people are literally obese. I see no reason why America wouldn't be the same (if not worse, taking in some considerations) than Australia.Jamesniederle (talk) 05:30, 4 November 2019 (UTC)#Reee/DD/rats.
Adding Skin Fold Body Density Formulas
Would anyone oppose me adding the most popular formulas for calculating body density from skin folds, such as Jackson & Pollock, Parillo, and Durnin & Wormersly? --BBUCommander (talk) 03:53, 7 March 2014 (UTC)
Accuracy of BMI
The language in the beginning of the article regarding the accuracy of BMI seems misleading. It says:
The widely used body mass index (BMI) provides a measure that allows for the comparison of individuals of different heights in terms of their weight. Due to differences in body composition, the BMI is not necessarily an accurate indicator of body fat; for example, individuals with greater muscle mass will have higher BMIs. The thresholds between "normal" and "overweight" and between "overweight" and "obese" are sometimes disputed for this reason.
This implies that BMI is inaccurate due to the number of false positives for obesity. However, it seems that the opposite is true -- most of the inaccuracy of BMI comes from the number of false *negatives* for obesity, i.e. the proportion individuals with normal weight BMIs but obese bodyfat percentages. Here are a bunch of studies which substantiate this:
Comparison of the classification of obesity by BMI vs. dual-energy X-ray absorptiometry in the Newfoundland population. — Preceding unsigned comment added by 22.214.171.124 (talk) 20:26, 4 June 2012 (UTC)
- You've misread at least the first two of your links--I've only looked at two so far--, and zero-for-two is not a good batting average. The first one says only that BAI is not an accurate measurement. The second one says only that BMI is better at determining how obese someone is than whether they're obese. In any case, the obvious essential problem with BMI is that it assumes the amount of non-fat tissue per height is fixed for all individuals at all times, and of course it isn't. Whether BMI tends to underestimate or overestimate fat depends on the fixed amount it assumes (its scale) and the individual. If the population on average has gotten less muscular (as may be a corollary of the very rapid spurt in average height of the past few decades, probably as a result of artificial chemicals in the environment or chemicals added to commercially-packaged food, affecting still-developing individuals), and the scale hasn't been accordingly adjusted, then BMI may tend to underestimate obesity, but only on average. The normal effect for older (unaffected by chemicals and additives because already fully grown) muscular individuals will still necessarily be to overestimate obesity. TheScotch (talk) 17:32, 13 February 2013 (UTC)
Women Body fat
recommend bf % for women according to first uncited source: article says acceptable range is 20-21% i.e. a 1% bf window. This has to be an error or typo and it should either be corrected or removed. —Preceding unsigned comment added by 126.96.36.199 (talk) 00:32, 14 February 2008 (UTC)
Agreed. In fact I think the whole stated range makes no sense. If men and women have a specific percentage of essential fat which is fixed, plus the fact that women have a higher percentage of storage fat than men, then the female figures are 1) too low compared to the men's and 2)there should be a wider range. Unforutnately, until more figures based on scientific studies are available, it's hard to back information up. —Preceding unsigned comment added by Dee26 (talk • contribs) 23:50, 20 February 2008 (UTC)
While it is true that on average women have a higher percentage of body fat, it doesn't follow that less muscle mass means a higher percentage of body fat. Women could simply weigh less and have a body fat percentage equal to men's.
The fact that women do have a higher body fat percentage begs better explanation. Perhaps the higher percentage is related to helping a woman survive the demands of pregnancy. At any rate, I think we should seek a more useful explanation than simply "less muscle mass." Rklawton 17:43, 10 February 2006 (UTC)
Reponse: uhm it's the general consensus that if two people have the same frame and one has a much larger bf% then the other one has more muscle mass. It's just mathematically obvious even if it hurts your feelings.
It is both reasons, less muscle mass and also more body fat for reproductive purposes.
breasts are almost entirely fat, and probably add a substantial percentage of difference in body fat, especially at the leanest levels.
- The size of breasts varies dramatically, however, which should throw an adjustable spanner into the works. TheScotch (talk) 11:32, 22 February 2013 (UTC)
New York Body Building Journal??
I've done a Google Search, a Google scholar search, scoured the Duke University Libraries, and cannot find any reference to this "New York Body Building Journal" let alone the article. If this journal does exist, then the citation should be updated to link to this article. If it doesn't, the claim that a body builder's joints are at risk from a low body fat needs a verifiable source or it will be removed. —Preceding unsigned comment added by 188.8.131.52 (talk) 18:57, 31 December 2007 (UTC)
Durnin Womersley skinfold conversion
I would like it if you would include the Durnin and Womersley skinfold conversion tables or a link to them.
Body fat percentage categories
That reference for ACE refers to an unreferenced chart from another web site. The reference is an undocumented loop. This chart is not adequately referenced. — Preceding unsigned comment added by 184.108.40.206 (talk) 16:15, 3 August 2011 (UTC)
I searched the American Council on Exercise web site for body fat percentage categories, and found no information about them there. Please provide the URL so that the info on body fat percentage categories could be verified. Thank you. Rightnow 11:09, 12 May 2006 (UTC)
I couldn't find information on the categories that the ACE website, but it appears on this website with ACE listed as a source. http://www.healthchecksystems.com/bodyfat.htm
Essential fat 2-5%? You're about to die if you're at 4%. These figures are not only wrong but dangerous!
- Essential means exactly that. You will die if it falls below that. Actually you would die much before that. nirax (talk) 12:42, 4 May 2009 (UTC)
Essential fat is 2-5%, but that's not the minimum recommended body fat percentage. There is a minimum recommended amount of storage fat on top of essential fat. Including the row marked "essential fat" in the chart is misleading, because nobody should be at that level. Note also that the range between 4 and 6 % for men and 12 and 14 % for women is missing in that oft-referenced chart. I believe this is the range within which bodybuilders compete. 220.127.116.11 19:37, 24 November 2006 (UTC)
I found this reference: http://www.healthchecksystems.com/bodyfat.htm . According to what is written there, the percentages are to be corrected.
Shouldn't the recommended body fat percentages be adjusted for age as well as sex? Neither the table in this article nor the table at http://www.healthchecksystems.com/bodyfat.htm make any distinctions between age groups. --18.104.22.168 20:28, 2 October 2006 (UTC)
Why are these numbers so hugely different from other sources: http://www.netfit.co.uk/ty5.htm http://lowcarbdiets.about.com/blbodyfatcharts.htm?once=true& —Preceding unsigned comment added by 22.214.171.124 (talk) 17:14, 17 June 2009 (UTC)
"Average"? - Shouldn't this read something like "Normal" or "Healthy" or some end state. If everyone is becoming obese won't the average continue to increase? In my mind this negates the value of the current source . —Preceding unsigned comment added by 126.96.36.199 (talk) 21:16, 28 September 2010 (UTC)
Before even coming on this talk page I had noted that this reference leads to no scientific source. I suspected that, it is highly possible that there is a scientific source and I had contacted the publisher of the article in question (http://www.acefitness.org/blog/112/what-are-the-guidelines-for-percentage-of-body-fat/) Dr. Natalie Digate Muth on her scientific source, to avoid original research, I will just state bluntly that she wasn't citing a specific source in the article because those were the numbers given to her by the ACE itself. I have since sent an email to them to see if there is a retrievable scientific source behind this at all. Also there needs to be a clear source for it all. It was noted above that essential body fat estimates were wrong if not dangerous, but then later suggested the table was in addition to essential fat, which would also be confusing. I think that should also be avoided and made clear.Jamesniederle (talk) 05:12, 4 November 2019 (UTC)
Acceptable to Obesity
How can you go from acceptable body fat directly to obese? Isn't there an overweight category?
Don't even get me started on this ha ha. It's very confusing because most people are used to using a BMI scale which has a normal, overweight and obese range. By going straight from acceptable to obese, it gives the impression that perhaps the acceptable figures are overweight when they are not (or at least not the lower end of the acceptable range). I think perhaps obese really means overweight or there needs to be an overweight range somewhere between the acceptable figures and obese figures...maybe the obese range should be higher to make more room for an overweight range. The problem is there is a lack of information and studies on body fat percentage, for example scientists still cannot agree on an obese body fat percentage for females. It was often stated as 30%, but scientists have now found the average woman has a body at percentage of 30% at only a BMI of 25 which is just into the overweight range and would be too low to call obese. So now scientists are saying 35% which correlates well with an obese BMI in the average female, other sources state 32% or 33% is obese for a female. It's just ridiculous that they can't set specific guidelines, I guess there just are not enough studies to back up the figures.
This is something like what you are looking for: http://www.weightwatchers.com/util/art/index_art.aspx?tabnum=4&art_id=20841&sc=803 188.8.131.52 (talk) 19:59, 24 May 2008 (UTC)
- If you define obese as dangerously overweight, that is, as overweight to the extent that health may or, perhaps, will be impaired, then the problem may be that the medical profession is necessarily unconcerned with the middle category. This is in contradistinction to the layman, who will tend to care very much about his appearance, especially about how attractive he is to the opposite sex. TheScotch (talk) 17:41, 13 February 2013 (UTC)
184.108.40.206: Weightwatchers is very far from scientific. The problem with your link is in the subtitle: "What BMI means, how it affects your health, and how to calculate yours." No, BMI is only valid for populations, not for individuals. If you want to know how fat you are (and merely looking in the mirror isn't good enough for you), have your body fat measured. TheScotch (talk) 10:32, 22 February 2013 (UTC)
Link to skinfold calculation is removed
Not sure why the skinfold calculators have been removed as spam? Should the others be removed as well?
I don't know about removing things because of spam. What kind of external links are allowed? I removed some links November 24th that were not related to true body fat percentage measures. Is that okay to do? —Preceding unsigned comment added by 220.127.116.11 (talk • contribs)
- See Wikipedia's External links policy. Also, please sign your posts by adding four tildes (~~~~) at the end. -- Mwanner | Talk 18:15, 24 November 2006 (UTC)
BMI to Body Fat Estimator
Added this link as I find this quite useful. Another alternative way to estimate your body fat percentage. Cheers! --Romansemko 14:08, 4 December 2006 (UTC)
- As the discussion on the site shows (as does common sense) it is just not an accurate method. I have removed it. -- Mwanner | Talk 14:52, 4 December 2006 (UTC)
YMCA Method : Remove or not remove?
This method gives a formula into which you have to put your height and weight, but it does not cite which units to use: metric or imperial. Looking at the formula, I would say that it would definitely make a difference. Are we talking inches and pounds, or centimeters and kilograms? 18.104.22.168 (talk) 11:01, 20 November 2007 (UTC)
- Either way, it seems to be inaccurate. I tried both metric and US units, and I got a negative body fat % for both. In reality, my body fat is actually 7%. So I don't know what's going on here. Savvy10 (talk) 14:09, 12 June 2008 (UTC)
Yeah, the top half of the equation shows roughly how much fat in pounds there is on your body, the bottom half should say weight*100. —Preceding unsigned comment added by 22.214.171.124 (talk) 20:34, 2 August 2008 (UTC)
- The given formula already underestimates way too much. If you further divide by 100, it would become even more inaccurate. May be you mean multiply numerator by 100. Anyway, does anybody know of any reference to it. Else we should remove this formula from the article. I have put a tag of lack of reference. nirax (talk) 12:37, 4 May 2009 (UTC)
Here's a calculator using this formula that claims a specific YMCA source: http://www.weightlosscalculators.org/Body-Fat-Calculator.aspx: "This calculator uses the YMCA formula from the YMCA guide to Physical Fitness Assessment." However, that doesn't appear to be a real book. There is book called the "YMCA Fitness Testing Assessment Manual": http://www.amazon.com/Ymca-Fitness-Testing-Assessment-Manual/dp/0736033165#reader. But no waist/weight calculation appears to be included in the current edition. I say this based both on looking at Amazon's index of the book as well as references to formula pages from the book on the web. Therefore I agree the formula should be dropped unless someone can come up with a copy of a book with the formula in it. (That said, when I ran the calculation for me it was very close to what my Tanita body fat scale says.) RollandWaters (talk) 20:43, 5 May 2009 (UTC)
The YMCA method seems a little odd! It calculates my bodyfat as 9% but I just had it measured at my gym (electronically) as 27%! —Preceding unsigned comment added by 126.96.36.199 (talk) 11:25, 1 September 2008 (UTC)
Someone needs to post a table comparing or ranking the relative accuracies of these methods. It's alright as it is, but would be nice to have some SE's for these measurements ex.(+-2%). —Preceding unsigned comment added by 188.8.131.52 (talk) 18:47, 31 December 2007 (UTC)
I find the last sentence ot the Recommendations section to be absurd: "It can be dangerous to maintain a body fat percentage at the low end of this range for more than a few days or a few hours." I understand that it can be dangerous to have so little fat, but that sentence seems to imply that people need to watch out for fluctuations in the short term. I have added a citation needed tag, because I am not convinced that body fat percentage can change significantly in a matter of hours, and be the cause of problems. —The preceding unsigned comment was added by 184.108.40.206 (talk) 18:11, 15 March 2007 (UTC).
The end sentence, stating that "5% is a physiological minimum for human males" is also absurd. I', at 3.03% body fat, which (in response to the comment above) is definitely in the low range, and I have had a BMI in this range for ages. I will admit, though, that I'm concerned about my weight. I'm 5' 8", weigh 107 lbs., and have a BMI of 3.03%. I have a normal diet, but I seem to be consistently losing weight.
In the typical body fat amounts section table, Men's Essential Fat is listed as "2-5%". However, the body of text below it attempts to refute the claim that male bodybuilders aim for the 2-4% range by stating "(b) 4-6% is generally considered a physiological minimum for human males." Since Essential Fat is basically defined earlier in this same paragraph to be the physiological minimum ("the level below which physical and physiological health would be negatively affected."), these two number ranges appear to be in conflict. — Preceding unsigned comment added by 220.127.116.11 (talk) 16:52, 11 June 2012 (UTC)
- You seem to be assuming that a bodybuilder would never do anything that might impair his health. This is a false assumption. In fact, at least several professional bodybuilders have died during competitions from too little body fat. The entire life-style (steroids, diet, etc.) is extremely unhealthy. In any case, you might bear in mind that professional bodybuilders attempt to lose body fat only directly before a contest. Between contests they're more concerned with bulking. TheScotch (talk) 18:07, 13 February 2013 (UTC)
Body average density measurement
This section does not identify the units in which volume and weight have to measured. Any ratio of physical units will give different values depending on the unit system used.Ludico (talk) 17:24, 8 April 2009 (UTC)
Omron vs. Tanita for BIA
The section on bioelectrical impedance measurement concludes with a statement that when looking at two brands of scale, one in particular overestimated the body fat.
Um, overestimated compared to the other one? Which one is right, then? Or, were both compared to something else? This could read like an advert for Omron. The source given is offline, so I don't have immediate access to it, nor do I have the inclination to find the original work.
The percentages in the table look descriptive, not 'recommended'. Unless someone recommended obesity!
Also, article does not explain why any "recommended" percent should be higher than the essential amount. It just says "The minimum recommended total body fat percentage exceeds the essential fat percentage." —Preceding unsigned comment added by 18.104.22.168 (talk) 02:16, 18 January 2011 (UTC)
Very surprised about not finding in this article information on hydrostatic weighing and Air Displacement Plethysmography (BodPod). Both methods calculate body fat based on the measurement of total body density. — Preceding unsigned comment added by AiGreko (talk • contribs) 19:16, 13 March 2011 (UTC)
- Unfortunately, the article as it currently reads still says that, for example, it is recommended that obese persons have body fat percentages of twenty-five percent or above, which, of course, is nonsensical. TheScotch (talk) 17:45, 13 February 2013 (UTC)
Discussion on reddit
I see someone did what I did today, someone else did 8 years ago or so. So it turns out that ACE admits that they don't have a scientific source and it's just a rational they use based on a few textbooks. Maybe it should be investigated more deeply and a better source actually found? Surely there have been new scientific studies regarding this issue.Jamesniederle (talk) 05:16, 4 November 2019 (UTC)
That formula is highly inaccurate. It gave a number for me that is half of what I get with both the navy method AND using calipers. As well, I plugged Ronnie Coleman's stats into it and it gave an estimated body fat of "49.81". That is not a "prediction error is comparable to the prediction error obtained with other methods of estimating BF%, such as skinfold thickness measurements or bioelectrical impedance", not even close. — Preceding unsigned comment added by 22.214.171.124 (talk) 09:24, 26 February 2012 (UTC)
- In the first place, BMI is supposed to be valid only for entire populations, not for individuals. In the second place, the "number" obtained from "calipers" is a body fat percentage, and the number obtained from BMI is another animal entirely. You're comparing apples and oranges. TheScotch (talk) 10:37, 22 February 2013 (UTC)
In addition the formula quoted is incorrect, the original formula has brackets, this will give a completely differnt result to the ones in the article. You first do x and÷ from left to right then + and- left to right. Without the brackets the formula will not work. — Preceding unsigned comment added by 126.96.36.199 (talk) 09:27, 4 October 2018 (UTC)
Accuracy _ study
This link has useful information on the various estimates (not measurements) of Body Fat %. http://weightology.net/weightologyweekly/?page_id=218 (Coachtripfan (talk) 16:56, 26 December 2013 (UTC))
Underwater Weighing error
From this article:
"body density can be determined with great accuracy by completely submerging a person in water and calculating the volume of the displaced water from the weight of the displaced water. A correction is made for the buoyancy of air in the lungs and other gases in the body spaces."
I believe that this is not accurate. The Underwater weighing procedure weighs the subject while immersed, so the weight of any displaced water is not relevant.
Determining the subject's volume from the weight of the displaced water could give a result comparable to the typical underwater weighing procedure - since the objective is to determine the subject's density - but then the volume of any residual gasses would need to be accounted for rather than their buoyancy.
The quoted text should be corrected to more accurately reflect the procedure described in the Hydrostatic weighing article.