BMI question. Calculation has me at a seriously low weight

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Jeff92se
Jeff92se Posts: 3,369 Member
in Health and Weight Loss
It has me at a target weight range of 118 - 160 lbs. 180lbs 5ft 7". MY BMI is 28.2

My current waist size is 32-33. I work out regularly but I signed up here to try to track my food closer. (great food tips here btw!).

I consider myself more muscular than the typical person. Not huge or anything. I have to get my % bodyfat done but let's say at 180lbs, I'm 22% bodyfat. Not unrealistic since I've lost 10lbs to get to 180. That's about 40 lbs of fat. At 0%, I'd weigh 140lbs. Well of course that impossible but it illustrates that the BMI calculation can't account for something that's holding more muscle tha "typical"? If I got down to 15% bodyfat, which would be pretty good for me, I'd be at 167.5llbs. 8 lbs over ideal.

In my case, should I ignore the BMI? But doesn't the BMI calculation determine the amount of calories I need to burn etc?
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Replies

  • mgmlap
    mgmlap Posts: 1,377 Member
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    Go to a nutritionist or a doctor who will give you a more realistic calculation. BMI does not take into account bone density, age, or even muscle...
  • tickletickle
    tickletickle Posts: 147
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    do what you feel healthiest at. Im lucky my goal is the higher end of my BMI
  • MikeSEA
    MikeSEA Posts: 1,074 Member
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    The BMI has nothing to do with individuals. It's about comparing populations. So no, BMI won't determine how much you need to eat or how many calories you need to burn in a day.

    You're thinking, I think, of your BMR, which still is just your Basal metabolic rate, not your TDEE (total daily energy expenditure)

    I think everyone should probably ignore the BMI.
  • Jeff92se
    Jeff92se Posts: 3,369 Member
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    True. Thanks. But the BMR still uses the same height, weight, age factors.

    I guess I'll see how the waist size and total weight goes for the next month or so.
  • TheWizeguy
    TheWizeguy Posts: 8
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    BMI is bull crap. How you can you not account for being male or female. We all know that muscle weighs more then fat, and woman have a higher percent of body fat then men. Hence the reason we love 'em! So no love lost ladies just that any system then figures out if you are overweight or under weight etc... needs to know more information then how tall you are and how much you weigh.

    Race, age, sex, muscle percentage, how often you exercise all need to be used to calculate a overall health indicator. BMI is bull. Get a body fat percentage done. You are exercising just fine.

    On top of that I'm a firm believer that you can carry extra weight and exercise and be 'healthy. On the flip side you can be skinny and get no exercise and be unhealthy. Weight is just a number. You're doing the right thing just keep at it.
  • barbiex3
    barbiex3 Posts: 1,036 Member
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    It has me at a target weight range of 118 - 160 lbs. 180lbs 5ft 7". MY BMI is 28.2

    My current waist size is 32-33. I work out regularly but I signed up here to try to track my food closer. (great food tips here btw!).

    I consider myself more muscular than the typical person. Not huge or anything. I have to get my % bodyfat done but let's say at 180lbs, I'm 22% bodyfat. Not unrealistic since I've lost 10lbs to get to 180. That's about 40 lbs of fat. At 0%, I'd weigh 140lbs. Well of course that impossible but it illustrates that the BMI calculation can't account for something that's holding more muscle tha "typical"? If I got down to 15% bodyfat, which would be pretty good for me, I'd be at 167.5llbs. 8 lbs over ideal.

    In my case, should I ignore the BMI? But doesn't the BMI calculation determine the amount of calories I need to burn etc?


    I'm sorry, but if you have a 32-33 inch waist you are not 22% body fat.... Especially at 180 pounds. You'd have to be like a football player/olympic athelete.

    http://www.scientificpsychic.com/fitness/diet.html

    that site is not 100% accurate with body fat percent, but it is a good estimate. I have a 25 inch waist, and I am two inches caller than you, and I'm barely under 20% body fat....

    I know it's hard, but try the calculator!!!
  • MikeSEA
    MikeSEA Posts: 1,074 Member
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    True. Thanks. But the BMR still uses the same height, weight, age factors.

    I guess I'll see how the waist size and total weight goes for the next month or so.

    Yeah, the Harris-Benedict equation actually seemed to work fairly well for me when I was trying to calculate how much I'm likely to burn in a day. I calculated that, try to eat 1000 under it per day and sure enough I'm losing about 2lbs per week these days. It's all very personal though.
  • chivalryder
    chivalryder Posts: 4,391 Member
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    If you're getting down to your ideal weight, I'd throw the BMI table out the window. As has been said, it is a general guideline for populations of people- not individuals. That being said, it is a good guideline to follow when initially losing weight, but when you've gotten close to your ideal weight, switch from the BMI tables and go with body fat %.

    IIRC, a good baseline BF% for men is around 15%. I'd say 15-17% if you wanna be "average joe," 10-15% is for people who are serious about their looks, or are into sports, and anything lower than 10% would have it's special reasons (say you're insane about your looks, or you're a sprinter).
  • barbiex3
    barbiex3 Posts: 1,036 Member
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    It has me at a target weight range of 118 - 160 lbs. 180lbs 5ft 7". MY BMI is 28.2

    My current waist size is 32-33. I work out regularly but I signed up here to try to track my food closer. (great food tips here btw!).

    I consider myself more muscular than the typical person. Not huge or anything. I have to get my % bodyfat done but let's say at 180lbs, I'm 22% bodyfat. Not unrealistic since I've lost 10lbs to get to 180. That's about 40 lbs of fat. At 0%, I'd weigh 140lbs. Well of course that impossible but it illustrates that the BMI calculation can't account for something that's holding more muscle tha "typical"? If I got down to 15% bodyfat, which would be pretty good for me, I'd be at 167.5llbs. 8 lbs over ideal.

    In my case, should I ignore the BMI? But doesn't the BMI calculation determine the amount of calories I need to burn etc?


    I'm sorry, but if you have a 32-33 inch waist you are not 22% body fat.... Especially at 180 pounds. You'd have to be like a football player/olympic athelete.

    http://www.scientificpsychic.com/fitness/diet.html

    that site is not 100% accurate with body fat percent, but it is a good estimate. I have a 25 inch waist, and I am two inches caller than you, and I'm barely under 20% body fat....

    I know it's hard, but try the calculator!!!


    I'm just seeing that you are a MALE now... so JK!!! I don't know what i'm talking about for men! I thought you were a female!!! sorry!!!!
  • Jeff92se
    Jeff92se Posts: 3,369 Member
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    It has me at a target weight range of 118 - 160 lbs. 180lbs 5ft 7". MY BMI is 28.2

    My current waist size is 32-33. I work out regularly but I signed up here to try to track my food closer. (great food tips here btw!).

    I consider myself more muscular than the typical person. Not huge or anything. I have to get my % bodyfat done but let's say at 180lbs, I'm 22% bodyfat. Not unrealistic since I've lost 10lbs to get to 180. That's about 40 lbs of fat. At 0%, I'd weigh 140lbs. Well of course that impossible but it illustrates that the BMI calculation can't account for something that's holding more muscle tha "typical"? If I got down to 15% bodyfat, which would be pretty good for me, I'd be at 167.5llbs. 8 lbs over ideal.

    In my case, should I ignore the BMI? But doesn't the BMI calculation determine the amount of calories I need to burn etc?


    I'm sorry, but if you have a 32-33 inch waist you are not 22% body fat.... Especially at 180 pounds. You'd have to be like a football player/olympic athelete.

    http://www.scientificpsychic.com/fitness/diet.html

    that site is not 100% accurate with body fat percent, but it is a good estimate. I have a 25 inch waist, and I am two inches caller than you, and I'm barely under 20% body fat....

    I know it's hard, but try the calculator!!!

    Well I just pumped in the numbers and on that site they estimate me at 14.7% Which I suspect is actually low.

    No probllem. I should upload an actual picture huh?
  • pinkgigi
    pinkgigi Posts: 693 Member
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    I'm 5'7" also, but my scale has me at about 34% fat. I am also very muscly (I do a lot of exercise, esp. bike riding) and when I had my bioage done, I was 90 percentile fitness for 25-29 year olds. I am about 169 pds. I think that you would definitely not be in the 22s for fat percentage at that height and weight. A better judge of healthy weight is supposed to be weight circumference, and for women it is meant to be under 30 inches, I think.

    GG
  • kneeki
    kneeki Posts: 347 Member
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    I wouldn't ignore your BMR, it's a great - and fairly accurate - way to determine your lean mass. Once you have those numbers down as close as you can, you can make reliable cuts to your caloric intake to help reduce your body fat.

    Going off of your example I'll use the Katch-McArdle formula. Even though it's accuracy goes up the leaner you become:

    180 lbs @ 22% body fat
    BMR = 370 + (21.6 x LBM) Where LBM = total weight (kg) x (100 - bodyfat %) / 100

    BMR = 370 + (21.6 x 63.67)

    BMR = 1745 calories

    So, if you work out, say, 3 times a week, your total calories consumed for MAINTENANCE should be: 2443

    Add +20% to that if you're trying to bulk, or, alternatively, subtract 20% to cut. Hope I made that clear... Heh. =)
  • Avalonis
    Avalonis Posts: 1,540 Member
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    BMI is garbage. You can pretty much completely disregard it.

    Go off ofbody composition. Thats what matters.
  • kneeki
    kneeki Posts: 347 Member
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    HERP! I read the title as BMR which is completely different than your BMI.

    Oh well.
  • Jeff92se
    Jeff92se Posts: 3,369 Member
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    HERP! I read the title as BMR which is completely different than your BMI.

    Oh well.

    Actually with no exercise calculated in, my daily is about 1,675. It's all good to read. BMR, BMI whatever. Thanks
  • ahinescapron
    ahinescapron Posts: 351 Member
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    BMI is not reliable, because it does not take into account muscle mass. You are much better off getting your body fat tested. Most gyms have the skinfold calipers, which are fairly accurate. I have a Master's in Health and Exercise Science and my professor basically told us BMI Is crap.
  • Jeff92se
    Jeff92se Posts: 3,369 Member
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    BMI is not reliable, because it does not take into account muscle mass. You are much better off getting your body fat tested. Most gyms have the skinfold calipers, which are fairly accurate. I have a Master's in Health and Exercise Science and my professor basically told us BMI Is crap.

    I was thinking of the biometric style. What do you think of those?
  • ahinescapron
    ahinescapron Posts: 351 Member
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    I am not sure exactly what you mean by biometric measures, since all these technically are classified as biometric measures. I think you are meaning measuring various body parts and using an equation. That is probably going to be more accurate than BMI, but still not the preferred method. I just don't want you to be working yourself to death based on a faulty number.
  • Jeff92se
    Jeff92se Posts: 3,369 Member
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    I am not sure exactly what you mean by biometric measures, since all these technically are classified as biometric measures. I think you are meaning measuring various body parts and using an equation. That is probably going to be more accurate than BMI, but still not the preferred method. I just don't want you to be working yourself to death based on a faulty number.

    It's the type that measures your % bodyfat via electrical connection.
  • MikeSEA
    MikeSEA Posts: 1,074 Member
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    BMI is not reliable, because it does not take into account muscle mass. You are much better off getting your body fat tested. Most gyms have the skinfold calipers, which are fairly accurate. I have a Master's in Health and Exercise Science and my professor basically told us BMI Is crap.

    I was thinking of the biometric style. What do you think of those?

    Like those machines that send pulses through your body as means of determining body fat %? They never seem to be accurate when I have that done.

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