The Student Room Group

BMI..a load of rubbish?

I recently went to my doctor and they calculated my BMI. Now I've been watching my diet and have been exercising a lot over the past few years and have dropped from an 20 to a size 14 and I am continuing to lose weight in a healthy way. However they still said that my BMI was between 30 and 31, ie I'm 'obese'.

Now back when I was a size 20 I might have agreed with them..but I don't feel or look obese now. Even the doctor doing the calculating was very surprised to see that I weigh a lot more than it might look like.

You always hear that the old excuse for overweight people is saying they are big boned. But can it be somewhat true? I do have a large bone structure, wide wrists, broad shoulders and a fair deal of muscle.

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Reply 1
BMI is only relevant if you have an average level of muscle etc.
Post a picture if you want to know whether you are really obese.
Reply 2
BMI is a load of crap, its useful only accross populations. Used with individuals it is neccessarily meaningless. Ignore it, and **** the police.
Speleo
BMI is only relevant if you have an average level of muscle etc.
Post a picture if you want to know whether you are really obese.

Agreed, it's all about the bodyfat percentage. For this reason lots of people who have a normal BMI because they have very little lean body mass but are actually chubby don't think they need to lose weight, when in fact they should weigh less than they do.

Equally, some people can have low bodyfat percentages but high BMIs (many professional athletes, for example).
Reply 4
The BMI is just a calculation using your height and weight and the tables are a guideline for what it means. your BMI will be the same because your weight is the same (unless youve shrunk?!) but you have to remember that if you have been exercising etc then the fat should have been converted to muscle, which weighs a hell of a lot more. go by what your doctor says, he should be looking at more than your BMI though.
By the way, well done on all the sliming!
lara400
the fat should have been converted to muscle

It is physiologically impossible to convert fat into muscle.
But you can burn fat and build muscle which is probably what they meant.
beach surf babe
But you can burn fat and build muscle which is probably what they meant.

Probably, but that's not what she said.

You'd be surprised at the amount of guys I know who have tried to get buff by stuffing their faces with pies and ice cream and crap and then trying to "convert" the fat into muscle.
Reply 8
rosetinted
I recently went to my doctor and they calculated my BMI. Now I've been watching my diet and have been exercising a lot over the past few years and have dropped from an 20 to a size 14 and I am continuing to lose weight in a healthy way. However they still said that my BMI was between 30 and 31, ie I'm 'obese'.

Now back when I was a size 20 I might have agreed with them..but I don't feel or look obese now. Even the doctor doing the calculating was very surprised to see that I weigh a lot more than it might look like.

You always hear that the old excuse for overweight people is saying they are big boned. But can it be somewhat true? I do have a large bone structure, wide wrists, broad shoulders and a fair deal of muscle.

If a doctor told you your obese, you're obese, end of..

However your BMI is generally a good way of telling how overweight you are, obviously it's not perfect, but you don't have to be very fat to count as obese.
Nah, body fat index is way more accurate.
Reply 10
Well I can safely say I'm not porking and trying to convert it into muscle.

I've had very physically active jobs for the past 3 years (ski teaching, white water rafting, outdoor activities instructor, punting..etc) so I'd say I probably have more muscle than other women my age. The girls I live with probably can't do one push up!

As for diet and exercise. I'm on a 1200 calorie per day diet, exercise 3 or 4 times a week, go for an hour long walk on the days I don't exercise and bike to and from uni. I'm also doing push-ups, sit-ups and twisting crunches in the morning and evening.
Reply 11
Body fat % is much more relevant, but it's also much harder to measure.
Reply 12
Eblis_O'_Shaughnessy
It is physiologically impossible to convert fat into muscle.


apoligies, apoligies, me being sloppy. did indeed mean that she may have reduced her percentage body fat, but increased muscle mass and therefore not necessarily lost masses of weight.
thankyou for picking me up on that little slip
lara400
apoligies, apoligies, me being sloppy. did indeed mean that she may have reduced her percentage body fat, but increased muscle mass and therefore not necessarily lost masses of weight.
thankyou for picking me up on that little slip

You can never tell if it's someone who knows what they're talking about phrasing it ambiguously or someone who genuinely believes it's possible to convert fat to muscle.

I'm glad you're the former!
I wouldn't worry according to BMI I'm very underweight but I'm healthy and I eat properly/exercise etc. BMI is just a rough indicator and doesn't give accurate results for everyone eg professional rugby players often have BMIs of 30+ making them morbidly obese when obviously they're not.
If your healthy and don't think your overweight then don't worry.
I think the best thing to do would be to measure your body fat percentage, which, correct me physio buffs if I'm wrong but, for a "normal" female should be between 20% and 30%? Less for athletes. If it's in the normal range then problem solved and ignore your BMI (within reason) and accept that you are one of those people who weighs a lot more than you'd think to look at them, but if this is still high then maybe you could do with losing a little more weight for your health's sake. I think the thing about "looking obese" can be really misleading because people these days are so much bigger built in every way than, say, 50 years ago, that people get used to seeing bigger individuals and gradually change their perception of what "overweight" looks like. I read a study in New Scientist which said that a really high proportion of people looking at photos of individuals who were medically obese classified them as looking "normal" in terms of their weight so...not saying you are btw, just an interesting point I thought!
Reply 16
in all fairness you probably are pretty fat if your bmi is 30-31
Reply 17
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Reply 18
This may sound abit personal but are you big busted or was you on your periods this may be the cause of you being "obese" truthfully me personally dont go by what the dr says :smile:
Reply 19
Kingers
in all fairness you probably are pretty fat if your bmi is 30-31


Not always. Mine is over 26 and I'm no where near 'fat' (I don't think). It's probably possible to look ok with a BMI of 30.