SmartBMI

Okohme
Okohme Posts: 152 Member
edited December 4 in Health and Weight Loss
So I was trying to figure out what my actual final goal weight should be, as I am approaching the top of my BMI range for a "normal weight" and came across a website that claims to take into account age with the calculation, something I had not encountered before. Anyone have any familiarity with this? It seems like its just an excuse to be a little heavier as you age, it tells me I am in a healthy weight range with BMI of 26.1.
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Replies

  • Okohme
    Okohme Posts: 152 Member
    Aaron_K123 wrote: »
    Okohme wrote: »
    So I was trying to figure out what my actual final goal weight should be, as I am approaching the top of my BMI range for a "normal weight" and came across a website that claims to take into account age with the calculation, something I had not encountered before. Anyone have any familiarity with this? It seems like its just an excuse to be a little heavier as you age, it tells me I am in a healthy weight range with BMI of 26.1.

    What would really make a BMI calculation more accurate is taking into account lean mass, how much muscle you have and your frame size is largely what is going to affect that. Now when you age you tend to lose lean mass so age is one round-about way to get there so maybe an age-adjusted BMI would be slightly more accurate than BMI, but chances are it is still going to be very off if you are not an average frame with average muscle mass.



    Well. Not very muscular. At all. (I'm working on it) The frame thing, I don't really understand because it seems to me, that at 5'3" my frame is going to be small. But logically I guess that isn't necessarily the case.
  • Okohme
    Okohme Posts: 152 Member
    edited November 2016
    Aaron_K123 wrote: »
    you can be short but large framed, your heigh doesn't matter in terms of frame size. Frame size is related to basically how thick your skeleton is (that is an oversimplification but yeah). Turns out there is something to being "big boned".

    I'm a 6' tall man. I have a small frame (light narrow bones). Because I have a small frame I'm actually lean at about 150 pounds which for a large framed 6' tall man would basically be dead from starvation.

    BMI is calculated just by dividing your Weight by your Height (thats it) and as such BMI makes some assumptions. It assumes you have the average frame and the average amount of muscle. If you have a large frame and a lot of muscle your BMI might be 27 even though you are in excellent shape simply because your extra muscle and heavier frame makes you weigh more than average for your height.

    I am small framed and probably have lower muscle than average (partly as a result) and so a BMI of 24 for me is probably still overweight even though its in the "healthy weight" category of the BMI scale.

    A simple way of getting an idea of your frame size is to do this:

    Take your thumb and middle finger and attempt to wrap them around your wrist at its narrowest point (assuming you don't have a lot of fat on your wrist and can actually feel the bone). If your fingers touch barely you have an average frame. If your fingers overlap you have a small frame. If your fingers don't touch at all you have a larger frame. Basically you are trying to measure the girth of your bones where your bone is most of the diameter of that part of your body (which is why its measured at your wrist which is basically just bone).

    If I do that I can put my thumb completely over the nail of my middle finger.



    Well, guess I am small framed. I have TINY wrists. So, I'm even fatter than I thought. Plugh. Oh well, onward.
  • Aaron_K123
    Aaron_K123 Posts: 7,122 Member
    Okohme wrote: »
    Aaron_K123 wrote: »
    you can be short but large framed, your heigh doesn't matter in terms of frame size. Frame size is related to basically how thick your skeleton is (that is an oversimplification but yeah). Turns out there is something to being "big boned".

    I'm a 6' tall man. I have a small frame (light narrow bones). Because I have a small frame I'm actually lean at about 150 pounds which for a large framed 6' tall man would basically be dead from starvation.

    BMI is calculated just by dividing your Weight by your Height (thats it) and as such BMI makes some assumptions. It assumes you have the average frame and the average amount of muscle. If you have a large frame and a lot of muscle your BMI might be 27 even though you are in excellent shape simply because your extra muscle and heavier frame makes you weigh more than average for your height.

    I am small framed and probably have lower muscle than average (partly as a result) and so a BMI of 24 for me is probably still overweight even though its in the "healthy weight" category of the BMI scale.

    A simple way of getting an idea of your frame size is to do this:

    Take your thumb and middle finger and attempt to wrap them around your wrist at its narrowest point (assuming you don't have a lot of fat on your wrist and can actually feel the bone). If your fingers touch barely you have an average frame. If your fingers overlap you have a small frame. If your fingers don't touch at all you have a larger frame. Basically you are trying to measure the girth of your bones where your bone is most of the diameter of that part of your body (which is why its measured at your wrist which is basically just bone).

    If I do that I can put my thumb completely over the nail of my middle finger.



    Well, guess I am small framed. I have TINY wrists. So, I'm even fatter than I thought. Plugh. Oh well, onward.

    Eh whether that is true or not the path forward in terms of your health is the same regardless. Don't obsess too much over exactly where you are at now, as long as you know how to start moving in the direction of better health the focus should be on doing that.
  • Okohme
    Okohme Posts: 152 Member


    Well, guess I am small framed. I have TINY wrists. So, I'm even fatter than I thought. Plugh. Oh well, onward.[/quote]

    Eh whether that is true or not the path forward in terms of your health is the same regardless. Don't obsess too much over exactly where you are at now, as long as you know how to start moving in the direction of better health the focus should be on doing that.[/quote]


    Well, I HAVE been moving in a good direction. some days I a, just ready to be "there" i guess.
  • jamcdonel
    jamcdonel Posts: 533 Member
    I am also a 6’ tall man. I used to weigh 150 pounds. Then in seventh grade...

    I have a very large frame. I have huge hands, and my fingers come nowhere near going around my wrist. Like not by 1.5 inches.

    I did an Ironman Triathlon 10 years ago. I weighed 210 lbs. on race day, about 12% body fat. Therefore BMI classified me as "significantly overweight". I couldn't get life insurance.

    BMI is BS.
  • geneticsteacher
    geneticsteacher Posts: 623 Member
    My doctor firmly believes in the age-based BMI. She believes that, especially for women, BMI should not be the same in your 50's and older as it was when you were in your 20's. She advocates carrying a little more weight AND strength training to prevent bone loss.
  • middlehaitch
    middlehaitch Posts: 8,486 Member
    A slightly higher BMI is often recommended for those who are older. The reasoning is that as one ages (55-60+), one is more likely to have illness and injury. The extra fat can be used if eating adequate calories is a problem.

    Could you link to the BMI calculator please. Just curious.

    Cheers, h.
  • SusanMFindlay
    SusanMFindlay Posts: 1,804 Member
    edited November 2016
    If I recall correctly, the "smart BMI" site also skews the acceptable ranges up slightly for taller people. Since there is a methodogical flaw* in BMI calculations that makes BMI values default to being higher when you're taller, accounting for this is actually smart.

    *Flaw = BMI compares a 2-dimensional property (height squared) with a 3-dimensional property (weight as a proxy for volume where volume would be a function of height cubed - though hopefully not actually height cubed! :smile: ). Unless you only grow in two dimensions (instead of three), when height is increased, height cubed (and therefore volume and therefore weight) increases by more than height squared. So, tall people should have their "healthy BMI range" extend higher. But we humans like our round numbers (and multiples of 5), so we're stuck with "convenient" cut-offs that are the same for everyone.
  • Okohme
    Okohme Posts: 152 Member
    middlehaitch wrote: »
    A slightly higher BMI is often recommended for those who are older. The reasoning is that as one ages (55-60+), one is more likely to have illness and injury. The extra fat can be used if eating adequate calories is a problem.

    Could you link to the BMI calculator please. Just curious.

    Cheers, h.

    I'm only 33, though.... :neutral:

    Here's the link
    smartbmicalculator.com/
  • Evamutt
    Evamutt Posts: 2,794 Member
    I can overlap my fingers too
  • leanjogreen18
    leanjogreen18 Posts: 2,492 Member
    edited November 2016
    Do wrists get fat? Can someone be big boned with small hands/fingers? Or small boned with big hands and fingers?

    There are actual measurements out there to find out what your frame size it but I was just wondering about the hand around the wrist thing, can it be wrong? Just curious...googling now.

    http://health.bizcalcs.com/Calculator.asp?Calc=Frame-Size-Wrist
  • Aaron_K123
    Aaron_K123 Posts: 7,122 Member
    geneticsteacher wrote: »
    My doctor firmly believes in the age-based BMI. She believes that, especially for women, BMI should not be the same in your 50's and older as it was when you were in your 20's. She advocates carrying a little more weight AND strength training to prevent bone loss.

    Well that is because your lean mass is most likely lower at 50 than it was at 20 so at equal weight you'd be fatter at 50 than at 20. That much is...on average...true. but if your doctor really cared to they could just measure your bodyfat percentage and find out directly instead of using a statistical inference that does not always apply.
  • Aaron_K123
    Aaron_K123 Posts: 7,122 Member
    Okohme wrote: »
    middlehaitch wrote: »
    A slightly higher BMI is often recommended for those who are older. The reasoning is that as one ages (55-60+), one is more likely to have illness and injury. The extra fat can be used if eating adequate calories is a problem.

    Could you link to the BMI calculator please. Just curious.

    Cheers, h.

    I'm only 33, though.... :neutral:

    Here's the link
    smartbmicalculator.com/

    Gave me 22.4.
  • Aaron_K123
    Aaron_K123 Posts: 7,122 Member
    jamcdonel wrote: »
    I am also a 6’ tall man. I used to weigh 150 pounds. Then in seventh grade...

    I have a very large frame. I have huge hands, and my fingers come nowhere near going around my wrist. Like not by 1.5 inches.

    I did an Ironman Triathlon 10 years ago. I weighed 210 lbs. on race day, about 12% body fat. Therefore BMI classified me as "significantly overweight". I couldn't get life insurance.

    BMI is BS.

    Yeah I'm the other side of that spectrum. I'm 6' but my wrist diameter is 6.25" so very small frame. At 188 pounds I was almost 28% bodyfat but BMI put me at barley overweight.
  • middlehaitch
    middlehaitch Posts: 8,486 Member
    IT says I am 19.3, or 29/70 for their calculations.
    Advised to gain 6 lbs for optimal weight, preferably muscle.

    Cheers, h.
  • courtneyfabulous
    courtneyfabulous Posts: 1,863 Member
    jamcdonel wrote: »
    I am also a 6’ tall man. I used to weigh 150 pounds. Then in seventh grade...

    I have a very large frame. I have huge hands, and my fingers come nowhere near going around my wrist. Like not by 1.5 inches.

    I did an Ironman Triathlon 10 years ago. I weighed 210 lbs. on race day, about 12% body fat. Therefore BMI classified me as "significantly overweight". I couldn't get life insurance.

    BMI is BS.

    Oh man that sucks there should be a way to appeal that denial on the basis that you are only 12% body fat! That's a very healthy range!!
  • SusanMFindlay
    SusanMFindlay Posts: 1,804 Member
    Aaron_K123 wrote: »
    Okohme wrote: »
    middlehaitch wrote: »
    A slightly higher BMI is often recommended for those who are older. The reasoning is that as one ages (55-60+), one is more likely to have illness and injury. The extra fat can be used if eating adequate calories is a problem.

    Could you link to the BMI calculator please. Just curious.

    Cheers, h.

    I'm only 33, though.... :neutral:

    Here's the link
    smartbmicalculator.com/

    Gave me 22.4.

    I think it calculates BMI normally just interprets it differently.

    I am moderately amused that it cautions me that my goal weight is "ambitious" when it corresponds to a BMI of 24ish - which is a good place for me personally. I don't personally feel the need to get halfway there then stop and maintain for a bit before continuing to lose. Maybe if my goal was a BMI of 20 that would be better advice. If I'd entered my starting stats, would it have cautioned me against losing the last 25 pounds "so quickly"?
  • tlflag1620
    tlflag1620 Posts: 1,358 Member
    Both my bmi and my "smart" bmi are 23.2. Maybe because I'm middle aged (36)? Not seeing how the "smart" bmi is any different... Is it just the ranges are different, not the actual number that gets spit out?
  • Okohme
    Okohme Posts: 152 Member
    tlflag1620 wrote: »
    Both my bmi and my "smart" bmi are 23.2. Maybe because I'm middle aged (36)? Not seeing how the "smart" bmi is any different... Is it just the ranges are different, not the actual number that gets spit out?

    It's the interpretation that is different, the calculation is the same. It looks like, to me, that they give a wider range of normal or healthy weights as you age, and that the overall healthy range is larger because being mildly overweight, in terms of BMI, is relatively low-risk for the various factors that they typically look at in association with being overweight or obese.
  • Okohme
    Okohme Posts: 152 Member
    sgt1372 wrote: »
    I don't know if SmartBMI is better but BMI is total rubbish.

    I am 5'8" and 163.4# w/16% BF which gives me a BMI of 24.8 barely w/in the normal range. At 165, I 'd be considered overweight at 25.1 and wouldn't reach the middle of the normal range unless I lost 20# more. I'd lose all of my muscle mass and look anorexic at that weight. That's complete nonsense! So, I put absolutely no stock in BMI.

    I think it might be a good tool for those of us who are pretty normal body type or even a little flabby. :neutral: I mean, I KNOW my weight isn't because of muscles or thick bones. Other people are obviously going to be different. Not really knowing my BF% though, I guess I don't know for sure that it isn't about right.
  • crzycatlady1
    crzycatlady1 Posts: 1,930 Member
    edited November 2016
    Okohme wrote: »
    middlehaitch wrote: »
    A slightly higher BMI is often recommended for those who are older. The reasoning is that as one ages (55-60+), one is more likely to have illness and injury. The extra fat can be used if eating adequate calories is a problem.

    Could you link to the BMI calculator please. Just curious.

    Cheers, h.

    I'm only 33, though.... :neutral:

    Here's the link
    smartbmicalculator.com/

    Never used that site before-just did it and it says I'm good I guess-"This assessment is based on the newly developed Smart Body Mass Index (SBMI). Its ideal range is between 30/70 and 39/70. Your SBMI is 33/70 or "33 points out of 70" "

    My 'regular' bmi is 21 and I'm 38 years old/female.
  • Derpy_Hooves
    Derpy_Hooves Posts: 234 Member
    edited November 2016
    Mmm I tried it but no real difference really. Normal BMI calculator gets me 22.2 and this one is 22.1.

    I think BMI calculators are great as a guideline, I know there's exceptions, so it won't work for everyone, but I'm sure for the majority of people it's a pretty handy tool.
  • cqbkaju
    cqbkaju Posts: 1,011 Member
    edited November 2016
    Don't use BMI. "SmartBMI" is an oxymoron.
    "Body Mass Index" was not meant to be used on individuals but for groups and populations.
    BMI implies elite bodybuilders and fitness models are obese.
    BMI is simply a lazy method to categorize people that tells you nothing abut their actual fitness level or health.

    Have your body fat measured and go from there. A dunk tank is best.

    If you cannot find someone to help you measure your body fat properly then get a cloth tape measure.
    Measure your waist at the naval/belly button every Wednesday morning after you use the bathroom but before you eat or drink anything.

    Track it consistently. Use this table to estimate your number:
    http://vitals.lifehacker.com/how-to-determine-the-number-of-calories-you-should-eat-1693372946

    As long as your waist size is going down a 1/2 inch or so every few weeks then you are probably on the right track.

    You can then plug your numbers into here to see how much you should be eating:
    https://legionathletics.com/macronutrient-calculator/
    Stick to 40% carbs, 40% protein and 20% fat for now, unless you have very specific training goals and know what you are doing.
    No more than a 20% or 25% deficit. Try to under-estimate your activity level.
    Use MFP to track what you eat.

    Make sure you are weight training so you are not losing more muscle than fat.
    Usually you should be doing more weight training than cardio.
    Failure to do this means at least 1/2 the weight you lose will be muscle.
    You are far more likely to put on fat -and therefor increase your body fat percentage- if you regain any weight.

    In other words, if you "lose 10 pounds" then 5 lbs of that could be fat and 5 lbs could be muscle.
    If you are not weight training hard enough and you regain those 10 lbs back then it will probably be 10 lbs of fat, which lowers your metabolic rate and makes it harder to "re-lose" those 10 pounds of fat.

    It is a vicious cycle. One of the few ways to minimize the threat it is through weight lifting.
    People that tell you otherwise are probably selling something, scared of hard work and/or spreading misinformation.
  • daniip_la
    daniip_la Posts: 678 Member
    Aaron_K123 wrote: »
    A simple way of getting an idea of your frame size is to do this:

    Take your thumb and middle finger and attempt to wrap them around your wrist at its narrowest point (assuming you don't have a lot of fat on your wrist and can actually feel the bone). If your fingers touch barely you have an average frame. If your fingers overlap you have a small frame. If your fingers don't touch at all you have a larger frame. Basically you are trying to measure the girth of your bones where your bone is most of the diameter of that part of your body (which is why its measured at your wrist which is basically just bone).

    If I do that I can put my thumb completely over the nail of my middle finger.

    Just commenting on this to say that the "fingers wrapped around the wrist" method isn't really accurate. Measuring your wrist and comparing it to charts would probably be better.

    For example, I'm 6'0" and my wrist measurement is 6.75", which is solidly in the large frame category. My thumb and pinkie can touch when I wrap them around my wrist. My thumb can overlap the other fingers when I try them, which would put me in the small frame category. My wrists are bony though, so I trust the measurements. I just have extra long hands/fingers, so the finger-wrap test doesn't work.
  • crzycatlady1
    crzycatlady1 Posts: 1,930 Member
    edited November 2016
    cqbkaju wrote: »
    Don't use BMI. "SmartBMI" is an oxymoron.
    It was not meant to be used on individuals but for groups and populations.
    BMI implies elite bodybuilders and fitness models are obese.
    BMI is simply a lazy method to categorize people that tells you nothing abut their actual fitness level or health.

    Have your body fat measured and go from there. A dunk tank is best.

    If you cannot find someone to help you measure your body fat properly then get a cloth tape measure.
    Measure your waist at the naval/belly button every Wednesday morning after you use the bathroom but before you eat or drink anything.

    Track it consistently. Use this table to estimate your number:
    http://vitals.lifehacker.com/how-to-determine-the-number-of-calories-you-should-eat-1693372946

    As long as your waist size is going down a 1/2 inch or so every few weeks then you are probably on the right track.

    Make sure you are weight training so you are not losing more muscle than fat.
    Usually you should be doing more weight training than cardio.
    Failure to do this means about 1/2 the weight you lose will be muscle.
    That means you are more likely to put on more fat -and therefor increase your body fat percentage- if you regain any weight.

    It is a vicious circle. One of the few ways to minimize the threat it is through weight lifting.

    My waist circumference was measured by a medical professional a few weeks ago-going by the link you gave, my 25 inch waist puts my bf% at 15 percent. I question if that's accurate, since I'm a mostly sedentary 38 year old female who's pear shaped.

    For me personally (and for my doctor), bmi has been a pretty solid tool throughout my weight loss phase and now maintenance.

  • cqbkaju
    cqbkaju Posts: 1,011 Member
    edited November 2016
    crzycatlady1 wrote: »
    My waist circumference was measured by a medical professional a few weeks ago-going by the link you gave, my 25 inch waist puts my bf% at 15 percent. I question if that's accurate, since I'm a mostly sedentary 38 year old female who's pear shaped.

    For me personally (and for my doctor), bmi has been a pretty solid tool throughout my weight loss phase and now maintenance.
    By definition I said it was an estimate in case you cannot have your body fat tested.
    I also said to track the number and make sure it was consistently going down every few weeks.

    I am trying to imagine what a 25-inch navel on a pear shaped person looks like and I am failing.
    That being said, I specifically say to measure at the belly button.

    I am guessing that is not where the "medical professional" -who probably knows less about fitness than most of the people on MFP- measured your "waist circumference."
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