BMI: is it a load of shit?

[libby]

i calculated my BMI the other day and worked out i'm in the healthy range, but thought that it doesn't seem to account for how much people vary (in build etc)

one of my friends who is really fit, he eats well doesn't drink heaps and is in great shape is considered overweight by thr BMI (he's not a bulky weightlifting type either)

anyone have better suggestions for assessing general physical health? just a simple body fat %? or are there better measures around

[Xpose]

In my opinion yes it is rubbish, work on your size measurements.

I used to buy into it until i heard a figure that most elite athletes ie footballers are considered overweight and somebody like Shaquille O'Neal is considered Obese.

edit - by size measurements i mean that your waist etc is in healthy range, maybe search for some basic fitness goals online eg - run a km in x minutes, be x flexible, do x amount of situps for your age.

[djbobbit]

A-grade baloney is what it is

Like the name suggests, its' a measurement of mere "mass". Obviously muscle weighs more than fat. Body fat percentage is a better indicator.

I'm sure there are others here who know more though.

[bricktop712]

if you're a muscular athlete then disregard the bmi completely as the bmi doesn't distinguish between fat and muscle - muscle weighs more than fat.

everybody else should still use the bmi.

[MadMike]

Any gym should be able to give you a quick fitness check (flexibility, blood pressure, skin fold caliper testing, lung capacity). BMI is used most commonly for cases of obesity, where skinfold measurement becomes inaccurate. At best a BMI can give you a guide to whether you are in a 'normal' range. Because BMI does not differentiate between fat and non-fat weight, it is inappropriate for athletes and naturally tall and thin people. The most accurate bodyfat measurement is hydrostatic (underwater) where the amount of water you displace is compared to your weight.

BMI is a rough guide, but your fitness in general should take into consideration a number of factors. Fat people can be fit, so body fat alone is no measure of fitness.

[MissAnge]

Im a bit :meh: on the BMI
1 month I was at 19% and the following month (else where) I was 30%.

[SpaceMonkey]

Any gym should be able to give you a quick fitness check (flexibility, blood pressure, skin fold caliper testing, lung capacity). BMI is used most commonly for cases of obesity, where skinfold measurement becomes inaccurate. At best a BMI can give you a guide to whether you are in a 'normal' range. Because BMI does not differentiate between fat and non-fat weight, it is inappropriate for athletes and naturally tall and thin people. The most accurate bodyfat measurement is hydrostatic (underwater) where the amount of water you displace is compared to your weight.

BMI is a rough guide, but your fitness in general should take into consideration a number of factors. Fat people can be fit, so body fat alone is no measure of fitness.

Agree with Mike, BMI is fine if a: you're of average build, and b: you're not carrying any muscle. But if you spend any amount of time lifting weights in the gym, you're probably going to be ruled out by B. I'm not what you'd call particularly big but I'm borderline obese according to my BMI (180cm and 93kg). Even at my ideeal weeight (prolly around 85kg) I'd be well overweight. MY girlfriend however (at 177cm and 57kg) is supposedly underweight, although in fact she's perfectly healthy.

[Dbauch]

anyone have better suggestions for assessing general physical health? just a simple body fat %? or are there better measures around
The only way I was able to assess myself was by doing some exercise and seeing how I felt during and after.

After 45 minutes of running or bike riding or playing a sport you should know if you are unfit :P

[supa]

most things are deceptive: the mirror lies, the scales screw with your head, BMI can be skewed for different reasons (eg. muscle mass), body fat tests are hard to self administer and really need to be done by professionals and the measuring tape doesn't take into consideration genetic differences (obviously a taller person could have a larger waist and not be fat).

in the end i've come to realise that all these things just mess with my mind, and i'd prefer not to fret over my weight like an anorexic-adolescent female!

my best guides are:
- progress photographs (sure you look different in pictures but at least you can track improvements)
- my honest brother
- my trusty fave pair of jeans (lee jeans circa 2000, given to me for my 18th birthday). i particularly like this method because if you increase your muscle mass and decrease your bodyfat (hence weighing more on the scales) the jeans fit looser, so you know you're heading in the right direction. but remember to never wash the jeans!!

[Spitchen]

BMI is a very old measure of obesity, scaling your weight by height. There are now much better measures in use.

Muscle weighs more than fat so those with big muscles are gonna be recorded as obese using BMI, when its apparent they are not.

Skinny marathon runners get recorded as underweight using BMI when its apparent they are not.

Skinfold thickness and bio-electrical impedance analysis are better measures although BMI is an ok tool for measuring whether sedentary individuals are "underweight," "overweight" or "obese".

[SpaceMonkey]

Skinfold thickness and bio-electrical impedance analysis are better measures although BMI is an ok tool for measuring whether sedentary individuals are "underweight," "overweight" or "obese".

Even then it should be taken with a grain of salft though as it doesn't allow for different builds, for example most polynesians would be considered obese according to their BMI because they are naturally much more heavily built than europeans.

[gravy]

according to BMI, as a 6 foot dude i could weight 65 kilos and be healthy. i reckon i'd be dead

[percy]

BMI is a load of crap if you do any sort of weight training, mine is a tad above 26. If you want to assess your general fitness, see if you can do half an hour of exercise, if you keel over and nearly have a heart attack after 5 minutes, then you know your fitness isnt too great. As already stated, a body fat % analysis doesnt doesnt really say if you are fit or not, just whether you are carrying more fat than you should be.

[SpaceMonkey]

In short, the answer to this thread's original question is that yes, in general BMI is a load of shit.

[didjeridude]

anyone have better suggestions for assessing general physical health?The gold standard for "general physical health" is an aerobic capacity test. If you can run or walk, one of the best estimates of VO2max is the Cooper test. You simply measure the total distance (in meters) that you are able to cover in 12mins. Use a formula to then predict VO2max.

Otherwise, doing a submax test on a cycle ergometer is almost just as good. Problem is that virtually no gyms have the proper equipment to do this sort of test (eg: a Monark cycle ergo), and the shite bikes they do use are rubbish and will give useless results.

Doing a simple lung function test (ie: FVC and FEV1) is also a good measure.

[Spitchen]

The gold standard for "general physical health" is an aerobic capacity test. If you can run or walk, one of the best estimates of VO2max is the Cooper test. You simply measure the total distance (in meters) that you are able to cover in 12mins. Use a formula to then predict VO2max.


I've got a Coopers test VO2max score of 66.95 based on 3500 metres covered in 12 minutes

[didjeridude]

I've got a Coopers test VO2max score of 66.95 based on 3500 metres covered in 12 minutesHey thats not too bad Spitch!! You should definately be aiming for a sub 1:30 half marathon then.

[Spitchen]

Hey thats not too bad Spitch!! You should definately be aiming for a sub 1:30 half marathon then.

Yeh, if i can keep the training going my aim would be to run 90-95 mins. Obviously its easy to maintain a quick pace over 12 minutes (sub 4min kms) but i'd have to run much more conservatively in a half marathon. I wanna make sure I finish the thing.

[Marzy]

According to the BMI I am obese

However, I had a 8-point skin-fold test done at the gym yesterday and it registered me at 5% bodyfat. I know they aren't the most accurate of things, but at worst it makes me 9-10% which is certainly not fat, let alone obese.

[Kinna]

Do the scales that calculate your BF% use the BMI methodolgy?

I swear its wrong! When I do the pinch test I get a totally different number.

[armo82]

BMI also doesnt take into account bone weight, according to the BMI i am very obese, alot of people class me as stocky, but not overweight

[custaro]

according to BMI, as a 6 foot dude i could weight 65 kilos and be healthy. i reckon i'd be deadThat's me! :lol: Except i'm 6'1 and weight 63.5.

I'm well and truly alive (and healthy) :thumb: