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How do we judge a healthy weight range? BMI is no longer valid?
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@MarkusDarwath I guess the only thing left to do is to wait and see what the status is when you get to 220. Since we are using bio-impendence estimations so the muscle mass measurement can be used, but loosely at this point, and we really don't know how much muscle mass you may lose while continuing to lose weight, it's kinda pointless to keep debating your stats. All I know is I wish you luck getting there, and look forward to reattacking this at that point.
I've actually just about made up my mind to pop for a dxa scan. I'm in a college town and the university offers it for $50. I'm not real clear tho on whether dxa can give me a breakdown between muscle and other lean mass. I'm hoping it can.
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Gallowmere1984 wrote: »That's why, when one is in the overweight category, the general advice is either "consider doing something about it", or "just don't gain anymore". It's not until they kick down the door on obese that the advice changes to "okay, seriously, fix yourself".
That's not very helpful to the people who are within BMI but over fat anyway.0 -
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Here's a read out from a scan I had done in March to give you an idea of what you will see.
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Looks like it doesn't really separate muscle out from other lean mass. Bummer. Stuck with BIA estimation on that point (assuming BIA BF% matches the dxa).0
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stephenearllucas wrote: »
Sorry if I'm pooing on your joke by being too literal here.. muscular asymmetry is normal due to left-right dominance. Some people might not know that.0 -
MarkusDarwath wrote: »BMI is just built off insurance risk tables though. Health risk increases over (or under) a given mass for a given height. Saying that Most People can't get a medical benefit from getting under a 25 BMI is nonsensical. All BMI is saying, literally (in the original sense of the word) is that Most People do get a health benefit from getting under a 25 BMI. What it doesn't say is which people are part of that "Most People" group.
Statistically speaking, most people -don't- get a particular benefit from being under 25BMI. The actual cutoff for increased risk is 30 for those without other health risk indicators, or 27-28 for those who do have other indicators (such as high blood pressure, glucose or cholesterol.)
The "overweight" category has no meaning by itself.
This isn't true. Under 20 or over 25 BMI risk does increase, particularly for men. This is a meta-study with a total of over 10 million participants in 239 studies of weight and risk of death, "all cause mortality", so correlation no proven causation, but a large chunk of people studied.
http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(16)30175-1/abstract
"Mortality was lowest in the
BMI range from 20·0 kg/m² to less than 25·0 kg/m²,
and was significantly increased just below this BMI
range and in the overweight range just above it."
Again, I want to say that I support aesthetic goals and do not believe you have any sort of obligation to get to the healthiest possible weight for your height. All of us make compromises in some direction, nobody is doing 100% of the "right things" to be healthy. When you have information, though, you can make an informed choice about it. Overweight does increase health risk.
What surprised me in this study was the increased death rate for those between 18.5 and 20 BMI, not the increase in overweight and obese. I would have thought that carrying less weight was healthier until you got to that 18.5, but that isn't borne out in the big study.
Good luck to you in getting to your personal goals.3 -
stephenearllucas wrote: »
Lol, I noticed that. No idea how it happens but I looked at my wife and said "must have been hangin' to the left" and winked at her.
She laughed pretty hard at that... Not sure why...9 -
This isn't true. Under 20 or over 25 BMI risk does increase, particularly for men. This is a meta-study with a total of over 10 million participants in 239 studies of weight and risk of death, "all cause mortality", so correlation no proven causation, but a large chunk of people studied.
http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(16)30175-1/abstract
Fair enough. I'm not going to try nitpicking details about quality of the base studies or the aggregation of studies across varying population groups. Given that aggregation studies tend to balance out flaws in component studies, one would have to basically re-do the meta-study to assess the validity of their conclusions, and that could well go either way.Again, I want to say that I support aesthetic goals and do not believe you have any sort of obligation to get to the healthiest possible weight for your height.
I'm pretty sure 15% body fat will be close to optimum healthy weight, regardless of how much muscle I add to it.
What surprised me in this study was the increased death rate for those between 18.5 and 20 BMI, not the increase in overweight and obese. I would have thought that carrying less weight was healthier until you got to that 18.5, but that isn't borne out in the big study.
I would imagine that's 1. difference in resilience in the face of accident or disease, and 2. people in that group being more physically active and prone to risk taking.
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BMi is still pretty relevant for the vast majority of people. Personally I am more focused on my goal BF% than BMI or weight, but that doesn't make BMI invalid or misleading.
I'm 181cm and 104KG (down from 124.7kg) That puts me still in the obese 1 category at 32 BMI. I wear a size 36 jean and can squeeze into a 34, and large shirts, my waist by the tape at the navel, is 40. I am wearing clothes now I wore in the past, prior to when I started lifting, at around 210. 3 solid years of lifting before packing on weight, changed my BMI by maybe 3 points, well within the "spread" of the healthy range once I get there.
I called BMI outdated myself before because I didn't want to acknowledge how overweight and plainly fat I had gotten, I kept telling myself oh BMI doesn't work for me....I accept it now because it is still a decent indicator of how much I still need to lose...When I get to a muscular and athletic looking 15ishBF% I doubt I will care what the BMI chart says. You think Usain Bolt cares at all what his BMI is or complains it doesn't apply to him because "insert excuse, big boned etc"....Only overweight people who haven't quite yet faced up to things really complain about the "unfairness" or "validity" of the old BMI chart11 -
MarkusDarwath wrote: »
That will be down to the sheer number of people here trying to achieve the same thing. About as representative of the general population as celebrities (will have built up a multi-dimensional Venn diagram in my head by the time this thread fizzles out).
(And this is where I declare my preference, aesthetically, for lanky geeks!)6 -
stephenearllucas wrote: »
Though not actually that off. I'm quite lopsided due to accumulated injuries. Gammy right foot meant that my right shin was almost an inch smaller than my left, a while back, though I seem to have stabilised it,vfinally, after many years of embarrassing falls. Conversely, developed a massive right forearm compared with left, due to a combination of knitting style and arthritic left elbow!MarkusDarwath wrote: »BMI is just built off insurance risk tables though. Health risk increases over (or under) a given mass for a given height. Saying that Most People can't get a medical benefit from getting under a 25 BMI is nonsensical. All BMI is saying, literally (in the original sense of the word) is that Most People do get a health benefit from getting under a 25 BMI. What it doesn't say is which people are part of that "Most People" group.
Statistically speaking, most people -don't- get a particular benefit from being under 25BMI. The actual cutoff for increased risk is 30 for those without other health risk indicators, or 27-28 for those who do have other indicators (such as high blood pressure, glucose or cholesterol.)
The "overweight" category has no meaning by itself.
This isn't true. Under 20 or over 25 BMI risk does increase, particularly for men. This is a meta-study with a total of over 10 million participants in 239 studies of weight and risk of death, "all cause mortality", so correlation no proven causation, but a large chunk of people studied.
http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(16)30175-1/abstract
"Mortality was lowest in the
BMI range from 20·0 kg/m² to less than 25·0 kg/m²,
and was significantly increased just below this BMI
range and in the overweight range just above it."
Again, I want to say that I support aesthetic goals and do not believe you have any sort of obligation to get to the healthiest possible weight for your height. All of us make compromises in some direction, nobody is doing 100% of the "right things" to be healthy. When you have information, though, you can make an informed choice about it. Overweight does increase health risk.
What surprised me in this study was the increased death rate for those between 18.5 and 20 BMI, not the increase in overweight and obese. I would have thought that carrying less weight was healthier until you got to that 18.5, but that isn't borne out in the big study.
Good luck to you in getting to your personal goals.
I think one of the more overlooked problems at lower BMI, particularly for women, is a sharp drop in bone density, which can severely affect mobility and overall health in later life. I suspect that correlation and causation may become muddied, with this issue. Though. After all, many skinny people get that way eating shite, too. if you live on tabs, instant coffee and toast, then you may have a BMI of 20, but you are likely to be malnourished.0 -
Getting an idea of what your lean body mass is (even if it's off by say 3%), you can get an ideal body weight if you know it and use this formula.
Your lean body mass divided by (1 minus the body fat percentage you want to be)
So say you're 120lbs lean body mass and want to be 20% body fat. Then apply the formula.
120/(1-.20)
120/.80= 150lbs
So 150lbs would be the target weight (approximate) to be at 20% body fat.
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This is misleading, generally when you lose weight you lose some lean body mass as well as fat. The exact proportion will depend on how you are eating, whether you are doing weightlifting, and how quickly you drop the weight. But you are never going to be able to keep ALL of the lean body mass.2 -
MarkusDarwath wrote: »
And if you use the NBA as a sampling, you'd think the average height is 3 inches taller than it actually is.7 -
It seems to me that this discussion is missing some critical information about statistics and populations. We should go back to the definition of the Body Mass Index. I'm going to use the Centers for Disease Control (US government) definitions as a fairly acceptable and standard authority.Body Mass Index (BMI)
Body Mass Index (BMI) is a person's weight in kilograms divided by the square of height in meters. A high BMI can be an indicator of high body fatness. BMI can be used to screen for weight categories that may lead to health problems but it is not diagnostic of the body fatness or health of an individual.
http://www.cdc.gov/healthyweight/assessing/bmi/index.htmlWhy is BMI used to measure overweight and obesity?
BMI can be used for population assessment of overweight and obesity. Because calculation requires only height and weight, it is inexpensive and easy to use for clinicians and for the general public. BMI can be used as a screening tool for body fatness but is not diagnostic.
http://www.cdc.gov/healthyweight/assessing/bmi/adult_bmi/index.html
There are two important gems in the above
1. BMI... is not diagnostic of the body fatness or health of an individual
2. BMI can be used for population assessment.
These two are actually related because BMI is developed as a population standard. What does that mean? It means that a lot of individual measurements (people's weights) can be looked at with statistical averages to describe the behavior of the group. However, any individual measurement (weight) may or may not fall in the statistical averages. Why is this important? It's important because in order to make correlations with health, statisticians have to invoke some rules (aka assumptions) such as the Central Limit Theorem. This actually obfuscates the underlying relationships with any individual measurement, although it makes population-based descriptions much simpler.
Healthy people of any given height will have a variety of weights that depend on their individual physiology and the fact that there is actually a range of % body fat that healthy people can have. It's not like a body has one exact percentage of fat at which that person is healthy, and anything over or under means they're ill or going to become ill as a result.
Things that determine an individual's weight
1. Body frame size and shape. Bigger frames fill in with more stuff. A person with wide shoulders and a long torso, for example, will have more mass filling in their body than another who has long legs but a shorter torso.
2. Musculature.
3. Body fat (which is also related to age and gender)
So basically, the data point "weight" at any given height is dependent on 3 different variables. That makes it a crude tool. Add to that, the BMI graph is a skew distribution, not normal distribution. It's got a fairly short tail at the low end because very low BMIs (a) are often caused by serious illness (or starvation) which frequently result in death, and (b) often lead to serious illness rapidly. On the other end, tail past the mean is much broader because (a) people can get pretty fat and (b) most fat-related illnesses are not imminently life-threatening so they can live while pretty fat for a long time.
It's also becoming increasingly apparent that not all body fat is the same.Maxematics wrote: »The only reason her body is more accepted is because a lot of her fat falls in places that are beneficial for her aesthetically by American standards. Had it all been at her stomach, she'd simply be dismissed as being overweight.
While Maxematics' comment is partially true (regarding aesthetics), from a health perspective, the distribution of weight is absolutely critical according to current understanding of fat. Visceral obesity is linked to much worse outcomes than storage of fat in the breasts, buttocks and thighs. It is specifically visceral obesity that is linked to diabetes, heart disease, and other things. The thing is, as people become more and more overweight, even if they're genetically predisposed to dump fat in areas far away from organs, they will start to accumulate fat around their organs. This is the origin of the discrepancy in health outcomes at various BMI levels between Asian populations and Northern European populations; more fat stored viscerally (abdominally) at lower weights.
Regarding that Lancet article, there was a very interesting observation there as well:At the opposite extreme, there was a substantially higher mortality not only among those in WHO's underweight category, but also in those with BMI 18·5 kg/m2 to <20 kg/m2, suggesting that in excessively lean adult populations underweight remains a cause for concern. We have no information about whether the BMI in underweight individuals was always low.
Di Angelantonio, Emanuele. "Body-mass index and all-cause mortality: Individual-participant-data meta-analysis of 239 prospective studies in four continents." (2016).
Something tells me that we're not going to see a cry for people to get their BMI above 20. Yet it's associated with just as much health risk as being between 27.5 - 30 BMI and a greater health risk than being between 25 - 27.5, according to that particular meta-analysis!
The Lancet published a critique that points to the need for caution when making policy decisions based on statistical analysis given known limitations in those analysis as well as the role of further study.Berrigan, David, Richard P. Troiano, and Barry I. Graubard. "BMI and mortality: the limits of epidemiological evidence." The Lancet (2016).
BMI is a crude reduction but the best tool we have which is generally accessible and inexpensive for looking at the relationship of weight and health. I haven't even gotten into the biggest problem with it, which is that it attempts to make the relationship of mass and volume follow a square relationship when they are cubic, leading to linearly increasing error in the metric itself as height increases (a problem which is probably messing up all sorts of statistical analysis on health in the first place).
I'm not rejecting its use, but noting that it has some very serious limitations and it should absolutely NOT be a gold standard on its own by which indivdiuals are judged to be healthy or unhealthy (much less a moral judgment point).9 -
Also I've been dying to share this. Because statistical distributions do not mean what people seem to think they mean. A LOT of people fall outside 1 standard deviation of the mean. A fair number fall outside two standard deviations. And in a world with 7.4 billion people, 14 million people fall outside 3 standard deviations. That's a lot of people!7 -
Also I've been dying to share this. Because statistical distributions do not mean what people seem to think they mean. A LOT of people fall outside 1 standard deviation of the mean. A fair number fall outside two standard deviations. And in a world with 7.4 billion people, 14 million people fall outside 3 standard deviations. That's a lot of people!
14M is .2% of 7.4B or 2 out of 1000 people. 14M is a lot of people but pretty insignificant when taken as a part of the world's population.3 -
Packerjohn wrote: »14M is .2% of 7.4B or 2 out of 1000 people. 14M is a lot of people but pretty insignificant when taken as a part of the world's population.
It's approximately the population of Norway and Sweden combined. Yet people meet folks from those countries all the time! It's utterly amazing.
Also, 3 standard deviations would be 0.3% or 22.2 million... An even greater number! I changed my math when I was confused by my own graphic /facepalm.
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