Talkback: BMI Calculator

I am an older male; i am 5ft 7" tall and weigh 10 stone currently. I have recently been told by a practice nurse that i am underweight. My wife thinks the same thing. My BMI says i am 21.75 - considered to be in the healthy weight range. What should i believe?


  • If your BMI is 21.75, you are not underweight.  What makes them think that you are?

  • No idea what an older male is but I'm pushing the higher end of 30 and am.
    170cm (7ft-7) and weigh 62.86 kg (9st 9lb)
    I have also put on weight since running as I have built some muscle and am currently the heaviest I have ever been image

    Going by me your a bloody porker  image but im happy I do not have the same practice nurse as you.

    Also worth noting that BMI is seriously flawed as its a 19th century calculation which squares the hight by the weight of a population. BMI also ignores waist size, which is a clear indicator of obesity level. BMI makes no allowance for the relative proportions of bone, muscle and fat in the body. But bone is denser than muscle and twice as dense as fat, so a person with strong bones, good muscle tone and low fat will have a high BMI because of this it is not uncommon for world class athletes to find themselves classified as overweight or even obese according to BMI.

  • Squeakz wrote (see)

    No idea what an older male is but I'm pushing the higher end of 30 and am.
    170cm (7ft-7) and weigh 62.86 kg (9st 9lb)

    You're a bit light for someone 7 1/2 foot tall image

  • ROFL fair point Rob image never noticed that ohh the joys of typo's (perhaps ive grown a few feet although last time I checked I was 5ft 7)
  • I agree with Squeakz, BMI is a realitively antiquated, none scientific way of measuring body index. It is crude in the extrememe. I have never made the average even when I had a body fat index of less than 9%. It doesn't factor in bone density or muscular physique. You'd be better off having your body fat measure by a qualified sports instructor. I'm 161cm tall with a bmi of 27 so technically I'm o

  • Get a body stat test, you can get these if you are a member of a gym, if you arent then I dont know where you would be able to get it done.

    I do them all the time at work and they are really accurate.

  • not sure your age,, but is your wife in the habit of lying to you... Do you think the practice nurse  is in cahoots with her.

     If you trust your partner and have not had reasons to believe they are a nasty evil person.then why not believe her in this. people never see themselves as others see them

  • My BMI is 19.53 which is less than the figure quoted as being considered unhealthy.

    I have had several BUPA medicals and at each one have had to discuss this with them and so I have asked the obvious question - so if I am not anorexic and eat whatever I want what are the health risks of having a BMI lower than that considered ideal?

    I am yet to get a satisfactory answer but if someone out there wants to tell me why I am unhealthy then I am all ears. As far as I am concerned I am thin and I'm sure Mrs Skinny would like a bit more to grapple with and snuggle up to but I'm not sure that merits a health warning.

  • RicFRicF ✭✭✭

    Go on to BMI NHS choices and use the calculator. It places the lower limit of healthy at 18.5. I'll take that. For my height, gender and age I could be within limits at 7st 10lb's.

    Currently I'm on 21.

    I'm of the opinion that those ranges of healthy/unhealthy were arrived at by measuring sick people in hospital beds compared to healthy ones walking around.

    That's statistics for you.

    According to a pre med I once had. They (medics) thought I was nearly dead. I was actually in race shape having run 27:01 for 5 miles the previous day. They're not used to low blood pressure, low weight and a HR of 35 bpm.

  • Pretty sure that most elite marathonners would come in as underweight on BMI.

    And rugby players obese.

    It's only a guide for the general public - not sports people.

    Are you healthy otherwise ?
  • VDOT52VDOT52 ✭✭✭
    Most make elite marathon runners are about 20 on the Bmi I think...

    Quick google search find this:

    Looks like I was wrong- Wilson Kipsang is just under the lower limit- but his bodyfat is incredibly low so that is the difference. If they worked on lean weight he would be towards the high end of normal
  • RicFRicF ✭✭✭

    I had a look at that page. I very much doubt if Mo Farah's BMI is as high as 21. 

    When Seb Coe was breaking world records he was said to weigh 8st 5lb's while being 5' 9" tall. Well Mo makes Coe look fat.

    Watching a replay of the last Olympics 10,000m, there wasn't one runner carrying visibly less fat than Mo.

    I've been on this subject on another thread. The responses have been quite revealing. 


  • Generally agree, but I've seen Mo lifting 3 times his weight, so he must have quite dense muscular fibres = mass = weight.

    As somebody mentioned previously BMI is extremely unfair to muscle mass. BTW, muscle is a lot more dense/"heavier" than fat...

  • For most people BMI is a useful tool to prompt people to think about their weight and whether they need to change their lifestyle. For that purpose it is sufficiently accurate, and we should be careful not to undermine it.

    But - for the reasons given above - there are better alternatives for active people who put thought into their diet / weight.

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