BMI
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onemanpeloton
Posts: 58 Member
I see a lot of seemingly educated people still using BMI to form part of their otherwise reasonable arguments in fairly complex discussions. Surely we are past using this method of measurement? When arguing over small details regarding exercise and nutrition, does BMI really have any place in the conversation?
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Replies
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The fact that BMI is not the only useful measurement, doesn't make it a totally useless measurement.34
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While BMI is not the be all and end all, it is still a very useful tool.
Because at the end of the day, most people fit within the statistical tool that is BMI.11 -
I find BMI useful because it gives me an idea of the person's weight/body when it is so different than mine.
Saying that someone is 5'9 and 145lbs doesn't give me an idea of a persons relative size, including an athletic 21.5 BMI gives me a much better idea.
And, although BMI is not the only measurement that should be taken into account, if someone is aiming for a lower (or higher) than normal BMI, it is reasonable to question why.
I think it is reasonable to include it as part of an intelligent conversation as long as all other facts/circumstances etc are taken into account also.
Cheers, h.
Sorry not well worded, it's past my bed time.14 -
When I look at a BMI chart, the "healthy" range for me spans 20kg. 20kg!!
Not only is that an incredibly broad range (25% of my body weight), it doesn't address body composition, which is arguably more important.
I understand its use for doctors giving very basic and very broad advice to a wide range of people who are extremely overweight and need a very rough number to aim for, but I don't see it's place in an intelligent conversation based on an individual subject and their specific needs19 -
I used it to set my long term goal. I get a nominal insurance discount for being there. I do have thicker than average bones, a larger than average head, and longer than average torso, so low end (6' 144lb) isn't a good place for me, but high end (180lb) seems ambitiously reasonable. I plan to be in good shape, but sculpting muscle or obsessing over fat percent isn't important to me2
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Is this a reference to this thread? https://community.myfitnesspal.com/en/discussion/10682410/need-help-and-advice-to-lose-more-weight-and-achieve-a-cyclist-climber-body2
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Is this a reference to this thread? https://community.myfitnesspal.com/en/discussion/10682410/need-help-and-advice-to-lose-more-weight-and-achieve-a-cyclist-climber-body
not exclusively although that thread does have elements of what I'm talking about, yes0 -
Is this a reference to this thread? https://community.myfitnesspal.com/en/discussion/10682410/need-help-and-advice-to-lose-more-weight-and-achieve-a-cyclist-climber-body
you think?!
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mattrus1989 wrote: »Is this a reference to this thread? https://community.myfitnesspal.com/en/discussion/10682410/need-help-and-advice-to-lose-more-weight-and-achieve-a-cyclist-climber-body
not exclusively although that thread does have elements of what I'm talking about, yes
I don't think that thread is the hill to die on. Regardless of the error rate involved with BMI, it's probably pretty accurate in predicting whether or not one is underweight if they are highly active. A BMI of 18.5 for a very active cyclist is likely underweight and will probably negatively affect performance (and I say that as a cyclist with a BMI of 18.5).
As for other mentions of BMI, it's not inaccurate enough that it should be disposed of completely, and for most people coming to this website, it's probably a good thing to keep an eye on. It also wouldn't hurt to choose goal weights for most people here based on BMI, especially if they don't have another way of accurately measuring their body fat.7 -
Yes, body composition is important but there are very few athletic persuits that require one to be outside a 'normal' BMI.
Because of its broad range why not include it in the conversation if one is aiming for a goal that will compromise muscle retention or leave one with too high a bf percentage to perform optimally.
How would you reply to questions like -
I'm 26, 5'6 and want to weigh 110 lbs so I can fit into size 00 jeans. I plan to crash diet on 800-900 cals to get there fast. Is this a good idea?
- without bringing BMI into it so the poster can see how she is compromising her health by weighing so little.
It is very hard to know a person's body composition without detailed descriptions or photos, neither of which are very forthcoming a lot of the time.
Cheers, h.7 -
mattrus1989 wrote: »Is this a reference to this thread? https://community.myfitnesspal.com/en/discussion/10682410/need-help-and-advice-to-lose-more-weight-and-achieve-a-cyclist-climber-body
not exclusively although that thread does have elements of what I'm talking about, yes
I don't think that thread is the hill to die on. Regardless of the error rate involved with BMI, it's probably pretty accurate in predicting whether or not one is underweight if they are highly active. A BMI of 18.5 for a very active cyclist is likely underweight and will probably negatively affect performance (and I say that as a cyclist with a BMI of 18.5).
As for other mentions of BMI, it's not inaccurate enough that it should be disposed of completely, and for most people coming to this website, it's probably a good thing to keep an eye on. It also wouldn't hurt to choose goal weights for most people here based on BMI, especially if they don't have another way of accurately measuring their body fat.
I think we've already concluded that it wasn't one thread in isolation, so no ones dying on any hills.
How can something with such a broad range of acceptable measurements be classed as "pretty accurate"? Using myself as the example again, I wouldnt consider a 25% range of variability to be "pretty accurate".
I'm intrigued about the relationship between BMI and being active. Why is 18.5 (a supposedly healthy level of BMI) unhealthy for a cyclist and how would it negatively affect performance?
For weight loss, it seems to me that taking measurements of key areas of the body (as MFP allows you to do) would give you a better indication of body composition vs weight.2 -
mattrus1989 wrote: »Is this a reference to this thread? https://community.myfitnesspal.com/en/discussion/10682410/need-help-and-advice-to-lose-more-weight-and-achieve-a-cyclist-climber-body
not exclusively although that thread does have elements of what I'm talking about, yes
I don't think that thread is the hill to die on. Regardless of the error rate involved with BMI, it's probably pretty accurate in predicting whether or not one is underweight if they are highly active. A BMI of 18.5 for a very active cyclist is likely underweight and will probably negatively affect performance (and I say that as a cyclist with a BMI of 18.5).
As for other mentions of BMI, it's not inaccurate enough that it should be disposed of completely, and for most people coming to this website, it's probably a good thing to keep an eye on. It also wouldn't hurt to choose goal weights for most people here based on BMI, especially if they don't have another way of accurately measuring their body fat.
+1
Considering how the OP resorts to loaded phrases like "seemingly educated people" and "intelligent conversation" in his posts so far it's clear he has a particular axe to grind.
There have been a couple threads recently in the Debate forum about the merits and limitations of BMI, and how it's best used. I'm sure the OP will find plenty of "intelligent conversation" over there.15 -
mattrus1989 wrote: »Is this a reference to this thread? https://community.myfitnesspal.com/en/discussion/10682410/need-help-and-advice-to-lose-more-weight-and-achieve-a-cyclist-climber-body
not exclusively although that thread does have elements of what I'm talking about, yes
I don't think that thread is the hill to die on. Regardless of the error rate involved with BMI, it's probably pretty accurate in predicting whether or not one is underweight if they are highly active. A BMI of 18.5 for a very active cyclist is likely underweight and will probably negatively affect performance (and I say that as a cyclist with a BMI of 18.5).
As for other mentions of BMI, it's not inaccurate enough that it should be disposed of completely, and for most people coming to this website, it's probably a good thing to keep an eye on. It also wouldn't hurt to choose goal weights for most people here based on BMI, especially if they don't have another way of accurately measuring their body fat.
+1
Considering how the OP resorts to loaded phrases like "seemingly educated people" and "intelligent conversation" in his posts so far it's clear he has a particular axe to grind.
There have been a couple threads recently in the Debate forum about the merits and limitations of BMI, and how it's best used. I'm sure the OP will find plenty of "intelligent conversation" over there.
I've no axe to grind. You'll notice my original post has plenty of question marks. This isn't a witch hunt, feel free to engage in the conversation and educate me....I'm not beyond listening to a rational argument.
But what seems out of sorts is when one half of a certain argument is made very accurately, insisting on weighing every gram of food precisely (for example) and the other half of that argument then uses BMI as some sort of basis to support their claims.3 -
middlehaitch wrote: »Yes, body composition is important but there are very few athletic persuits that require one to be outside a 'normal' BMI.
And the usual complaint is that athletes are on the high side of BMI/overweight/obese if you don't take into account composition.
Outside of woman's gymnastics and maybe figure skating I can't think of any other athletic sports where the low end of the BMI scale is an athletic advantage.9 -
mattrus1989 wrote: »mattrus1989 wrote: »Is this a reference to this thread? https://community.myfitnesspal.com/en/discussion/10682410/need-help-and-advice-to-lose-more-weight-and-achieve-a-cyclist-climber-body
not exclusively although that thread does have elements of what I'm talking about, yes
I don't think that thread is the hill to die on. Regardless of the error rate involved with BMI, it's probably pretty accurate in predicting whether or not one is underweight if they are highly active. A BMI of 18.5 for a very active cyclist is likely underweight and will probably negatively affect performance (and I say that as a cyclist with a BMI of 18.5).
As for other mentions of BMI, it's not inaccurate enough that it should be disposed of completely, and for most people coming to this website, it's probably a good thing to keep an eye on. It also wouldn't hurt to choose goal weights for most people here based on BMI, especially if they don't have another way of accurately measuring their body fat.
I think we've already concluded that it wasn't one thread in isolation, so no ones dying on any hills.
How can something with such a broad range of acceptable measurements be classed as "pretty accurate"? Using myself as the example again, I wouldnt consider a 25% range of variability to be "pretty accurate".
I'm intrigued about the relationship between BMI and being active. Why is 18.5 (a supposedly healthy level of BMI) unhealthy for a cyclist and how would it negatively affect performance?
For weight loss, it seems to me that taking measurements of key areas of the body (as MFP allows you to do) would give you a better indication of body composition vs weight.
do you understand statistics at all and standard deviations? 25% of the population will fit into typically 1 standard deviation of the avg population - which is why they pick that range10 -
deannalfisher wrote: »mattrus1989 wrote: »mattrus1989 wrote: »Is this a reference to this thread? https://community.myfitnesspal.com/en/discussion/10682410/need-help-and-advice-to-lose-more-weight-and-achieve-a-cyclist-climber-body
not exclusively although that thread does have elements of what I'm talking about, yes
I don't think that thread is the hill to die on. Regardless of the error rate involved with BMI, it's probably pretty accurate in predicting whether or not one is underweight if they are highly active. A BMI of 18.5 for a very active cyclist is likely underweight and will probably negatively affect performance (and I say that as a cyclist with a BMI of 18.5).
As for other mentions of BMI, it's not inaccurate enough that it should be disposed of completely, and for most people coming to this website, it's probably a good thing to keep an eye on. It also wouldn't hurt to choose goal weights for most people here based on BMI, especially if they don't have another way of accurately measuring their body fat.
I think we've already concluded that it wasn't one thread in isolation, so no ones dying on any hills.
How can something with such a broad range of acceptable measurements be classed as "pretty accurate"? Using myself as the example again, I wouldnt consider a 25% range of variability to be "pretty accurate".
I'm intrigued about the relationship between BMI and being active. Why is 18.5 (a supposedly healthy level of BMI) unhealthy for a cyclist and how would it negatively affect performance?
For weight loss, it seems to me that taking measurements of key areas of the body (as MFP allows you to do) would give you a better indication of body composition vs weight.
do you understand statistics at all and standard deviations? 25% of the population will fit into typically 1 standard deviation of the avg population - which is why they pick that range
I do understand statistics. Do you understand the art of reading a post properly and understanding it?
I'm talking about giving specific advice to individuals based on their personal circumstances. It's foolish to apply an average to an individual. Imagine what the world would be like if everyone actually had 2.4 children......
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middlehaitch wrote: »Yes, body composition is important but there are very few athletic persuits that require one to be outside a 'normal' BMI.
And the usual complaint is that athletes are on the high side of BMI/overweight/obese if you don't take into account composition.
Outside of woman's gymnastics and maybe figure skating I can't think of any other athletic sports where the low end of the BMI scale is an athletic advantage.
And if you look at the stats for most of the Olympic female gymnasts, thanks to the muscle, most of them are actually in the 20-22 BMI ballpark.3 -
collectingblues wrote: »middlehaitch wrote: »Yes, body composition is important but there are very few athletic persuits that require one to be outside a 'normal' BMI.
And the usual complaint is that athletes are on the high side of BMI/overweight/obese if you don't take into account composition.
Outside of woman's gymnastics and maybe figure skating I can't think of any other athletic sports where the low end of the BMI scale is an athletic advantage.
And if you look at the stats for most of the Olympic female gymnasts, thanks to the muscle, most of them are actually in the 20-22 BMI ballpark.
Many of them are tiptoeing around the bottom end according to this... https://www.topendsports.com/events/summer/science/gymnastics-all-round.htm
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middlehaitch wrote: »Yes, body composition is important but there are very few athletic persuits that require one to be outside a 'normal' BMI.
Because of its broad range why not include it in the conversation if one is aiming for a goal that will compromise muscle retention or leave one with too high a bf percentage to perform optimally.
How would you reply to questions like -
I'm 26, 5'6 and want to weigh 110 lbs so I can fit into size 00 jeans. I plan to crash diet on 800-900 cals to get there fast. Is this a good idea?
- without bringing BMI into it so the poster can see how she is compromising her health by weighing so little.
It is very hard to know a person's body composition without detailed descriptions or photos, neither of which are very forthcoming a lot of the time.
Cheers, h.
Sorry, I missed this reply somehow.
I would still argue that its broad range makes it less useful, not more so. Again, if I was a government health minister, publicising advice to a nation then this would be slightly more useful. However, in the context of the individual it appears rather rudimentary to me?
With regards to your proposed question, I would probably answer that a given weight doesnt mean you're going to fit in to a pair of jeans. You could hold more weight on your hips naturally, lose weight from other parts of your body to get to your target weight and still not fit in those jeans.
Like I said before, key body measurements alongside weight would make more sense to me. I dont think photos are necessary1 -
mattrus1989 wrote: »mattrus1989 wrote: »Is this a reference to this thread? https://community.myfitnesspal.com/en/discussion/10682410/need-help-and-advice-to-lose-more-weight-and-achieve-a-cyclist-climber-body
not exclusively although that thread does have elements of what I'm talking about, yes
I don't think that thread is the hill to die on. Regardless of the error rate involved with BMI, it's probably pretty accurate in predicting whether or not one is underweight if they are highly active. A BMI of 18.5 for a very active cyclist is likely underweight and will probably negatively affect performance (and I say that as a cyclist with a BMI of 18.5).
As for other mentions of BMI, it's not inaccurate enough that it should be disposed of completely, and for most people coming to this website, it's probably a good thing to keep an eye on. It also wouldn't hurt to choose goal weights for most people here based on BMI, especially if they don't have another way of accurately measuring their body fat.
+1
Considering how the OP resorts to loaded phrases like "seemingly educated people" and "intelligent conversation" in his posts so far it's clear he has a particular axe to grind.
There have been a couple threads recently in the Debate forum about the merits and limitations of BMI, and how it's best used. I'm sure the OP will find plenty of "intelligent conversation" over there.
I've no axe to grind. You'll notice my original post has plenty of question marks. This isn't a witch hunt, feel free to engage in the conversation and educate me....I'm not beyond listening to a rational argument.
But what seems out of sorts is when one half of a certain argument is made very accurately, insisting on weighing every gram of food precisely (for example) and the other half of that argument then uses BMI as some sort of basis to support their claims.
Weighing food (in the context of calorie counting) and BMI are two very different discussions with different parameters.
Weighing food comes up mostly where people complain of eating at a deficit and not losing (or sometimes of eating enough but not gaining for those trying to bulk). When a person is claiming to eat 1200 calories a day, it helps to discuss how they are determining that.
BMI is primarily used for population studies because it can be easily calculated with reliably accurate measurements (tape measure and a scale). Using body fat percentage measurements for indexing population statistics is problematic because it's more labor intensive and has a higher error band in measurements (due to different people taking measurements, more points needed, etc).
For an individual, BMI is a useful starting point in discussing their present situation, or their goals based on where it puts them in compared to the population statistics. For a very broad portion of the population, BMI tracks with BF% enough that BF% doesn't change the assessment much if at all. For the much smaller portion of the population who are outliers, like elite athletes, those other measurements become much more necessary.
Statistically, there are elevated health risks correlated with both overweight and underweight BMIs. The 'healthy range' is broad because there is much lower risk associated with that range. If a person is seeking a goal in the low or high BMI ranges, it is useful to discuss those goals in more detail.10
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