Body Mass Index



  • Is the Body Mass Index something to tell you if you're overweight? I'm very sceptical of a BMI because it doesn't seem to take into account people's  body shape or build, nor does it seem to take into account how much muscle someone has. For example, the BMI of most top class props would say that they are overweight, even if they've got bugger all fat on them.

    For those interested, you can calculate your BMI by dividing your weight in kgs, by your height in metres, squared. Apparently, a BMI over 25 is overweight, and a BMI of over 30 is obese? So thus, my BMI has pretty much always shown me to be overweight, even when I was playing full-on school or club footy and training like a fucking psycho.

    Sounds like bullshit. Can someone explain it to us?



  • There are charts that doctors have had for years which measure developmental growth for children, and also average height/weight for adults. These things are a guide only and yes if you've got the skeletal structure of some form of human/rhino cross then BMI often isn't much use for you. If you're lean like a distance runner it will also feed you bullshit.

    My height is 180cm and my weight is 118kg. My BMI is therefore about 36 so technically I'm obese, but I'd actually put myself on the borderline between obese and overweight. I know I'm overweight but its not all fat - I have a huge skull (getting the aircraft warning light put in next week) and fairly broad skeletal structure so I'll probably always be overweight.

    Even if I reach a perfectly suitable goal weight of 100kg and can run around like a mad bastard all day, the BMI calculator still has me at nearly 31. To get back under BMI=25, I'd have to 81kg and that is 37kg away



  • same height here pretty much NTA, and at 105kgs.  so should be what, 2.15 metres tall or something to be the right weight.  Basically a pile of shit.



  • excellent thanks lads....I thought it was shit, just needed confirmation.

    [quote name='Nick the Aussie'] My height is 180cm and my weight is 118kg. My BMI is therefore about 36 so technically I'm obese, but I'd actually put myself on the borderline between obese and overweight. I know I'm overweight but its not all fat - I have a huge skull (getting the aircraft warning light put in next week) and fairly broad skeletal structure so I'll probably always be overweight.

    Even if I reach a perfectly suitable goal weight of 100kg and can run around like a mad bastard all day, the BMI calculator still has me at nearly 31. To get back under BMI=25, I'd have to 81kg and that is 37kg away
    [/quote]

    For some reason I thought you were taller than that Nick? Were you standing on a box in your wedding photos? 😁 You looked about 6'3 in those pics I reckon.

    Yeah, well I'm 187cm and 99 kg which puts me at 28...still overweight. But if BMI's are bullshit then I'll just ignore it. :coolsmiley:



  • If the BMI was correct then almost all International rugby forwards would be counted as being morbidly obese.  The BMI doesnt take into account bodyfat or muscle mass which is just as well in my case!



  • My scales have some sort of body fat monitoring device, calculated using your weight, height and some electrical pulses that it sends through your body. When I saw them in the shop, I had to have them because it sounded like such crap.

    Anyway, my healthy body fat range is, apparently, 8% to 20%. This evening I registered 36.4%Â



  • those things are bollocks!  I was woring in a pharmacy once, doing the one hour photo lab ting, and would work nights to get the next day photos sorted.  ANyway, boring as fuck, so one night used them, drank about three litres of water, jumped on, and my BF had gone up, and all it was was water, obviously.  So a load of shit...Â

    Aren't they...?



  • [quote name='BartMan']
    those things are bollocks!  [/quote]

    MvJ certainly hopes so; classic "as seen on TV" infomercial kind of product.



  • Yeah I would have to lose nearly 30% of my bodyweight to not be overweight and while I won't quibble with obese (120kg's 1.89m) if I was there target weight I'd slip through cracks in the footpath and unlike you guys I'm not carrying loads of muscle.



  • [quote name='Red Bull']
    For some reason I thought you were taller than that Nick? Were you standing on a box in your wedding photos? 😁 You looked about 6'3 in those pics I reckon.[/quote]

    Yeah thanks Mrs the Aussie isn't the tallest girl in the world  but I likes em small I does :twisted:

    The electric pulses for body fat are no real indicator. They can be wildly inaccurate depending on how much you sweat, how hyrdated you are, and whether you're standing on the precise points for them. Body pinch is the only way.



  • BMI is crap esp for stocky types with strong legs ,Michael Jones in his playing days and pro even McGod would be told to lose weight if you listened to BMI, so don't!
    proof:[url]http://nhlbisupport.com/bmi/bmi-m.htm[/url] (metric or imperial)
    try inputtng some AB players. I think Richie is 187cm and around 106-110kg now?
    Dan Carter is 28.7BMI-->fatso!



  • Yup, it's bollocks: body fat percentage is a more meaningful measure.  Needs some skill to get it right (calipers etc).  Athletes will have 6-13% body mass made up of fat, fit to fat bastard 'normal' people will range 14 - 25%, and over 25% is 'obese'.  15% is a good target.



  • Carl Hayman - 193cm, 120kg, BMI = 32.2 = OBESE!!!!!!!
    Phil Waugh - 175cm, 100kg, BMI = 32.7 = OBESE!!!!!!
    Tatafu Polota-Nau - 181cm, 113kg = 34.5 = OBESE!!!!!!

    And on it goes. Locks and backs are mostly 25-30, and front row and back row mostly 30+ except for the really tall guys.



  • I had a doctor pull the BMI shit on me once when I went to see him for a work medical certificate for having a flu.

    I would need to be under 110kg to not be obese, I haven’t been that weight since my uni days where it was normal to spend atleast 2 hours or so exercising each day.  Never gunna happen again I am afraid, unless cut off a leg or something.



  • I changed jobs a couple of yrs ago and realised I had no life insurance all of a sudden.  Insurance co. tried to load my insurance premium 100% because my BMI was 34 (well OK and the liver function and cholesterol results but still)



  • At 25.5, MvJ is on the cusp of normality  This must be incorrect...



  • Lack of muscle mass MvJ - most people store some weight as fluid too, whereas you're storing it as alcohol



  • [quote name='Nick the Aussie']
    [quote name='"Red Bull":3grdfv65']
    For some reason I thought you were taller than that Nick? Were you standing on a box in your wedding photos? 😁 You looked about 6'3 in those pics I reckon.[/quote]

    Yeah thanks Mrs the Aussie isn't the tallest girl in the world  but I likes em small I does :twisted:

    The electric pulses for body fat are no real indicator. They can be wildly inaccurate depending on how much you sweat, how hyrdated you are, and whether you're standing on the precise points for them. Body pinch is the only way.
    [/quote:3grdfv65]

    What about that thing they do on biggest loser, when you get in a huge tub and float while you're hooked up to some wires. Someone explain that in lamens terms for me???



  • :-k No fucking idea mate. Something about the density of fat and muscle - muscle is about three times heavier for the same volume.



  • Nicko after a bit of research its called - Hydrostatic Weighing to Measure Body Fat

    [quote]Hydrostatic weighing (underwater weighing) is the [b]most accurate way to calculate body fat [/b] - that is, if you can find a hydrostatic weighing tank.

    How does hydrostatic weighing calculate body fat? By using Archimedes Principle. Your examiner first calculates your body density by measuring the amount of water you displace when you immerse yourself in water. Then a formula is used to calculate body fat based on your body density. The problem is finding a facility (University, major gym or fitness center) which has a hydrostatic weighing tank[/quote]



  • Problem is the formula can be flawed if e.g. you have lots of muscle and displace much water but don't have that much fat. :nta



  • Yeah, water displacement wouldn't tell you %'s fat, muscle, bone, Banrock Stn.  Must be more to it than that



  • [quote]Problem is the formula can be flawed if e.g. you have lots of muscle and displace much water but don't have that much fat[/quote]

    Hmm: not heard of it before, but that doesn't sound quite right Nick: if it's done properly, they should be getting two measurements from such an action:

    a) The body volume - from displaced water.

    Your known weight - set of scales

    Knowing muscle, bone and fat densities, it's then just (!) solving a simultaneous equation to get the answer.  I can see room for a few errors, but would agree that - in theory - it should be bloody accurate, if someone knows what they're doing.



  • Agreed Death - there shouldn't be a lot of room for error for most people but for seriously fat people they could be waaay off. "The Biggest Loser" show features women as high as 170kg and men as heavy as 195kg without being that tall.

    Also complicating this is that even obese people who can still move under their own power tend to have a fair bit of muscle, because otherwise they wouldn't be able to move at all. The muscle might be marbled like prime beef but its still there. The ultimate problem is, as with BMI, they're going off assumptions of what the [i]average[/i] humans surveyed come out at, and don't necessarily take into account the skeletal structure of a person, which under all that fat is bloody hard to measure even though the density remains the same.



  • A quick update, apparently BMI has been adopted by all insurance companies because the reinsurers have adopted it.

    Anyway I am still discussing my case with and they are starting to look at other measures and are considering giving me a separate medical.  No guarantees yet though and they are reserving the right to fall back on the BMI as grounds for rejecting me.



  • Go in there and challenge any of their execs to a live scrummaging session. That'll see how fit the bastards are



  • The agent would love this idea, he is South African ad we end up talking rugby for 3/4 of the time when he calls me.



  • Yeah BMI is a load of crap, the bad thing is some insurance companies use it so 'obese' people like us have to pay higer premiums



  • Bring in the stats for All Blacks and ask them to explain why they are considered obese.



  • here a link for some cool things

    [url="http://www.bmi-calculator.net/"]http://www.bmi-calculator.net/[/url]

    I would burn  2137.68 calories if I lay in bed all day doing nothing.

    I am also in the obese range.  31.something.

    Reckon I have a bodyfat percentage of 16.3.  based on my weight and waist measurement.  That mewasurement is not in the obese category, but in the fitness category.



  • 33.77 (Obese class 1) even with my recent weight loss At my absolute peak a couple of years back I was nearly 39

    If WHEN I get to my goal weight I'll be 29.83, just short of obese, and probably fitter and stronger than every bastard who designed the BMI



  • 36.12 at my heaviest.  whit was 118kg.  now at a sevete 103, but still obese....  :nta



  • We should rename it the Bullshit Mass Indicator



  • [quote]You have a BMI of 27.82.

    BMI is between 25 and 29.9 (Overweight)[/quote]

    Am I fuck. Best shape I've been in ages. I can just pich an inch of fat around my waist.



  • 32.99 so the BMI is bs all ends up coz I'm as out of shape as I've ever been. I also appear to have discovered a new body shape.  I'm neither pear or apple - more like 40 gallon drum.


Log in to reply