Body fat % and age
professorRAT
Posts: 690 Member
I have been reading a bit about body fat percentage charts and age. It looks to me like the charts were originally constructed as a way to make adjustments to body fat percentage estimates (specifically those that measure subcutaneous fat), but are now being used as body fat goals by age (and maybe they should not be?). [here is an example of the chart: http://www.builtlean.com/2010/08/03/ideal-body-fat-percentage-chart/]
Here is my take on what I have been reading. As we age, we collect more intramuscular and visceral fat. So, our subcutaneous fat might be low (and we look very lean), but caliper measurements will be underestimating our true body fat percentage because it doesn't pick up the visceral and intramuscular fat. To me, this simply means that caliper method error rises with age. It does NOT imply that we should target a higher fat percentage goal simply because we are older. Is this correct?
In fact, it implies that we may want to seek out more accurate ways to estimate our body fat percentages as we age (ike DEXA) because calipers will not be able to pick up changes in anything other than subcutaneous fat. The charts are simply meant to help us make the appropriate adjustment to our overall body fat estimate when using calipers. Subcutaneous fat loss is likely correlated with fat loss in the other two types of fat, but I suspect this correlation is weaker in the extremes (especially individuals who are very lean in terms of subcutaneous fat?) and, in this interpretation, certainly weaker as we age.
[I am speaking more in terms of health oriented goals rather than vanity. For aesthetics, subcutaneous my be all that matters, but certainly for health reasons overall fat matters.]
Primarily I just wanted to ask you knowledgeable peeps if you think I have interpreted this correctly.
Here is my take on what I have been reading. As we age, we collect more intramuscular and visceral fat. So, our subcutaneous fat might be low (and we look very lean), but caliper measurements will be underestimating our true body fat percentage because it doesn't pick up the visceral and intramuscular fat. To me, this simply means that caliper method error rises with age. It does NOT imply that we should target a higher fat percentage goal simply because we are older. Is this correct?
In fact, it implies that we may want to seek out more accurate ways to estimate our body fat percentages as we age (ike DEXA) because calipers will not be able to pick up changes in anything other than subcutaneous fat. The charts are simply meant to help us make the appropriate adjustment to our overall body fat estimate when using calipers. Subcutaneous fat loss is likely correlated with fat loss in the other two types of fat, but I suspect this correlation is weaker in the extremes (especially individuals who are very lean in terms of subcutaneous fat?) and, in this interpretation, certainly weaker as we age.
[I am speaking more in terms of health oriented goals rather than vanity. For aesthetics, subcutaneous my be all that matters, but certainly for health reasons overall fat matters.]
Primarily I just wanted to ask you knowledgeable peeps if you think I have interpreted this correctly.
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This is an interesting post - tagging to think about it/look into it further. Quick comment for now however, very good points about subcutaneous v visceral fats and it also brings out flaws in some of the BF estimation methods such as caliper tests. Calipers also are full of errors for other reasons with regard to 'how much fat' they can grab for different body types.
Will get back to this one.0 -
I got nothing. But this is interesting and I will think on it.0
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Bumping this to remind me to do some homework0
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Thanks! No hurry at all, mostly just my nerdy curiosity again
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I am all for nerdy curiosity!0
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Tagging! (yes I'm totally nerdy-curious right now)
http://www.health.harvard.edu/fhg/updates/Abdominal-fat-and-what-to-do-about-it.shtml
http://www.mayoclinic.com/health/belly-fat/WO00128
http://www.ncbi.nlm.nih.gov/pubmed/18845966
http://hes.wfu.edu/assets/ribisl/Ribisl Toxic Waist Dump H&FJ.pdf
If I'm reading all of this correctly, then visceral fat is closely related to waist circumference.0 -
Tagging--I've been thinking about intramuscular fat a lot. I don't think there is any doubt as to age-related increases in visceral fat, just from the gerontology research I've seen. On intramuscular fat specifically:
http://www.karger.com/Article/FullText/182084
Edit: also, the epidermis thins out with age, so it makes sense that the calipers would return a lower bf% all other things being equal.0 -
I'm "ideal" for my age, 45 @ 18-19% But I'd like to see what I look like a 12-15%
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I've wondered about this too, but from a different perspective...
Are the studies that show an increase in visceral and intermuscular fat done on an athletic population or an average population? There are studies that show loss of lean muscle mass with age, based on average people, yet those who do weights can halt and even reverse this trend. in other words, the decline in muscle mass was more associated with being sedentary than with getting older (many people get more sedentary as they age), and it's not an inevitable consequence of aging.
If the studies that show this were done on average populations, I'd question whether an athletic 40-50 year old really does have more visceral and intramuscular fat than an equally as athletic 20 something with the same size skinfold. And what about comparing a sedentary 20 something with an athletic 40-50 something?
No idea if that's the case or not, but IMO these are questions for further studies. And there are too many variables. Anything based on averages will be wrong for a lot of people.0 -
I've wondered about this too, but from a different perspective...
Are the studies that show an increase in visceral and intermuscular fat done on an athletic population or an average population? There are studies that show loss of lean muscle mass with age, based on average people, yet those who do weights can halt and even reverse this trend. in other words, the decline in muscle mass was more associated with being sedentary than with getting older (many people get more sedentary as they age), and it's not an inevitable consequence of aging.
If the studies that show this were done on average populations, I'd question whether an athletic 40-50 year old really does have more visceral and intramuscular fat than an equally as athletic 20 something with the same size skinfold. And what about comparing a sedentary 20 something with an athletic 40-50 something?
No idea if that's the case or not, but IMO these are questions for further studies. And there are too many variables. Anything based on averages will be wrong for a lot of people.
Exactly! These are my thoughts as well. That is why I think using the term "ideal" in this context may be VERY misleading. Are these just averages from the population? If so, it implies NOTHING about "ideal"!0 -
If I can still get it up at 70 I figure I'm ahead of the game.0
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I've wondered about this too, but from a different perspective...
Are the studies that show an increase in visceral and intermuscular fat done on an athletic population or an average population? There are studies that show loss of lean muscle mass with age, based on average people, yet those who do weights can halt and even reverse this trend. in other words, the decline in muscle mass was more associated with being sedentary than with getting older (many people get more sedentary as they age), and it's not an inevitable consequence of aging.
If the studies that show this were done on average populations, I'd question whether an athletic 40-50 year old really does have more visceral and intramuscular fat than an equally as athletic 20 something with the same size skinfold. And what about comparing a sedentary 20 something with an athletic 40-50 something?
No idea if that's the case or not, but IMO these are questions for further studies. And there are too many variables. Anything based on averages will be wrong for a lot of people.
Exactly! These are my thoughts as well. That is why I think using the term "ideal" in this context may be VERY misleading. Are these just averages from the population? If so, it implies NOTHING about "ideal"!
I doubt that a funding agency would shell out money for a study of 40-50 year old athletes--they would not be of primary interest to either gerontologists (too young and healthy) or exercise scientists (too old to compete)... And they would not be good controls. Just guessing here, though--this is not my field.0 -
I like that chart - at last there is some benefit to being an old fart 0
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My husband works for CdC. I'm going to ask him to look into this. Very interesting concept.0
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tagging.. it's a subject of interest.
My personal experience: I'm a LOT leaner at 48 than I've ever been. IMO, that comes from diet more than exercise though.0 -
Sorry for the delay in getting back with findings. I have found a few things but want to read and address in the context of the question - will try to finish and post over the weekend. Just really rebumping this for the time being.0
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Were there any conclusions on this ?
I am quite curious as well.0 -
I'm curious as well.0
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I've wondered about this too, but from a different perspective...
Are the studies that show an increase in visceral and intermuscular fat done on an athletic population or an average population? There are studies that show loss of lean muscle mass with age, based on average people, yet those who do weights can halt and even reverse this trend. in other words, the decline in muscle mass was more associated with being sedentary than with getting older (many people get more sedentary as they age), and it's not an inevitable consequence of aging.
If the studies that show this were done on average populations, I'd question whether an athletic 40-50 year old really does have more visceral and intramuscular fat than an equally as athletic 20 something with the same size skinfold. And what about comparing a sedentary 20 something with an athletic 40-50 something?
No idea if that's the case or not, but IMO these are questions for further studies. And there are too many variables. Anything based on averages will be wrong for a lot of people.
Here is a link to a fantastic talk by an ER doc who lifts and does a ton of research on aging. He calls lifting "making a deposit into your physiological 401K." The talk is aimed at coaches at a Starting Strength Coaches Conference, but is well worth a listen.
http://startingstrength.com/index.php/site/video/sss_jonathon_sullivan0 -
This is an interesting concept, but it seems like a hypothesis without any data or actual observation. You're starting with an idea and looking for studies to support it?0
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^no, I actually have seen research that suggests visceral fat rises with age, which is the justification for the above chart that adjust bf% goals by age. It doesn't appear to be controversial, and that is not what I am questioning. The chart implies that, as we age, we should accept a higher bf% as "healthy". But, as far as I can tell, these numbers are simply adjusting for the observation that older people have more visceral fat AS IF that implies it is OK from a health standpoint. I actually think this information is being misused. If it is just an observation of bf% in aging populations, that implies NOTHING about healthy bf% goals. I have a feeling this is what they are doing, so I am questioning the wisdom of using this chart to determine health ideals.
Secondarily, if most people use methods that estimate subcutaneous fat as their measure, they will miss their actual [higher] bf% due to visceral fat. If this has negative health implications, then it would become more important to obtain more reliable estimates of overall bf% as we age (because we may not catch the visceral portion with less accurate methods).
I don't really have a hypothesis. I am simply trying to determine how these charts are constructed. In other words, what research support these targets for bf%? Or are they just population (or sample) statistics? If so, that really has nothing to do with health ideals. Part of my confusion might be the use of the term "ideal", "average" and "above average". An average is just a population statistic. Ideal implies something else. Mixing the two terms in this chart makes me suspicious.0 -
It is an interesting idea.0
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I'm "ideal" for my age, 45 @ 18-19% But I'd like to see what I look like a 12-15%
Well at least that chart is encouraging. I made it to lean, after starting here in January barely in the above average range. But the question I have from a vanity standpoint is, can a man my age (58) get down lean enough (at leas subcutaneous fat) to show the six pack. I sure seems almost like the impossible dream. I'm close (probably around 17% bf) but to get down to 10-12% to get closer seems like a real long stretch.
The other question I've been wondering is how to find a place anywhere near me that does DEXA testing for body fat. Is that something any place that does a DEXA scan would do, or is that more specialized?0 -
I found a place where i live by searching the internet for "DEXA body composition" with my city name and found a place that way. I think any place with a DEXA can do this analysis, but I don't know if they are willing. There are places, however, that specialize in weight loss that will often do them. You will likely have to pay out of pocket. The place I found did one for $100.
As for the abs, it really seems to vary from person to person. Mine start to show at a very high bf% because I carry very little fat in my torso (most in my legs), but for some people they need to be super lean to see their abs. It's another one of those crappy things we have no control over
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Interesting update:
I decided to pull out my old DEXA scan report and I saw a page there that I hadn't looked closely at before (it is a long report). On this page there is a list of "Standards" and this quote
"Health standards reflect the percentage of body fat that generally does not increase your risk for health problems"
The percentages for this "health standard" correspond somewhat to the AVERAGE area on the charts above. For men over 40 the healthy range is reported at 10 - 25%, and for women over 40....wait for it.....25 - 38%! In other words, if you are at or below the top of this bf% range you are considered healthy and not at increased risk for health problems due to excessive body fat. There is also a discussion of fat distribution, and other statistics to use to determine if belly fat is too high, but this differs from the way I thought people generally interpreted this chart.
My average bf% is higher than I expected because I carry lots of fat in my legs and very little in my torso. My torso bf% is in the ideal range and the bf% of my legs is literally off the chart! This makes my average bf% fall at the upper side of average, but, of course, with a very low belly fat ratio (and why my abs show at a very high average bf%).
Still, I found this interesting and I encourage everyone to have a DEXA for body comp analysis at least once. Bottom line: looking at weight, BMI or even average bf% alone can be very misleading in terms of health standards. Distribution of fat matters, too, and some of us have pretty freaky fat distributions! :ohwell:0 -
That's fascinating. Any chance you could scan that info? I'd love to read it in full.0
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Distribution of fat matters, too, and some of us have pretty freaky fat distributions! :ohwell:
I know I do!0 -
That's fascinating. Any chance you could scan that info? I'd love to read it in full.
Sure! Will do!0 -
If this idea is true (and it seems like it could be) then I would expect to be able to find studies hat also show the revere--decreased intramuscular fat levels from resistance training in adults of a certain age.
All I'm saying is, I doubt it's a one-way road if true.0 -
Well I don't see any in my town that offers it (DEXAs are used for useless purposes like bone density and actual medical diagnosis. lol). I'll see if there is anything in DC which is reachable. It may be worthwhile.
But I don't know if anyone interested here is in San Jose, California, but there is currently (and I don't know for how much longer) a Groupon being offered for $79 for a DEXA scan and body composition analysis. That seems like a real good price for anyone who is interested who is anywhere near San Jose. I know the way to San Jose (thanks to my fellow alumnae Dionne Warwick) but it's all the way across the country. Damn it.
http://www.groupon.com/deals/premiere-scan0
