Body Mass Index (BMI)

By October 11, 2011November 14th, 2014Health Coaching

Let’s carry on with our talks on weight management.  If you haven’t already, thern take a look at this one for a bit more insight. It is such a big concern for a lot of ladies out there, including myself, that I do want to focus a lot of my attention on it.  In terms of personal growth, it can be such a sticking point for ladies.  You may be feeling on top of the world and then you catch a glimpse of yourself in the mirror and all of a sudden, all that matters is how fat you think you are.  In some cases, your weight is really not all that bad but in other cases, a little help is required.  For all you women out there, I hope this helps.  As always, feel free to mention anything that you would like to know about.  If private, tell me and I will not publish the comment but respond to you directly.

Anyway, off we go…

Today, I am going to discuss one way in which health professionals assess your risk of weight related diseases.  I am sure it will make you aware of what really counts when considering controlling your diet or various weight loss solutions.

Body Mass Index

Is there anyone out there who has not heard of this?  Possibly, well this is for you.  This is usually the first thing that is measured when considering how to classify your risk factors and whether you are overweight or obese.  Body Mass Index (BMI) measures your total weight relative to your height.  This allows professionals to classify you as obese or not without just basing it on your weight.  It does not measure body fat however so it is not completely accurate but it does give a basic estimate.  It is considered THE standard at the moment.

Consider this example, Sarah and Lucy might weigh 11stone (154 pounds or 70kg). Sarah’s height is 5’ 9” (1.75m) while Lucy is 5’ 5” (1.65m).   Now, 11 stone can seem to be a huge number but relatively, Sarah has a BMI of 22.9 which is healthy while Lucy (unfortunate girl) has a BMI of 25.7 which has just crossed over into overweight.  As you can see, same weight, different assessment.

BMI is calculated as one’s weight (in Kg) divided by height (in meters) squared.

There are other ways to calculate it as well as shown on the Wikipedia site.  I have pasted a few in here.  It seems this method of measuring weight was developed sometime between 1830 and 1850 by a guy called  Adolphe Quetelet.  I wonder what made him think of it.  It used to be called the Quetelet index until the 1970s when it was realised that obesity was becoming a concern in westernised societies.  A research paper was released by Ancel Keys stating however that Body Mass Index should be used only when considering whole population groups.  He felt it was inappropriate for use in individuals but it became popular as it meant health professionals such as myself could objectively talk with patients about their weight – People do get a bit defensive if you are talking too personally about how fat you might think they are.  This way we can show very clearly that there is or is not a problem whether over or under weight.

So, go on, calculate your BMI. For a nice site for measuring it, click here.  Or here, if you are based in the UK – Gotta love the NHS! Actually, it works for everyone.

Where do you fit?  Look at the table below.



Risk of disease

Underweight Less than 18.5 Low (except for other
issues such as mental health concerns, lack of menstrual
periods etc)
Healthy Weight 18.5 – 24.9 Average
Overweight 25.0-29.9 Mildly Increased
Obese Class 1 30.0 – 34.9 Moderate
Class 2 35.0 – 39.9 High
Class 3 Above 40.0 Very High

Obtained (and made prettier- although I cannot see my borders in Firefox! anyone know how to sort that out!) from the National Institute of Clinical Excellence


There are limitations to the use of BMI in checking how healthy you are, one of which I have already mentioned.

  1. It does not measure body fat, which is quite important.
  2. It was developed originally for white Caucasian populations so it may not be completely accurate for other racial groups.
  3. If you happen to be super muscular, it probably does not give an accurate measure of whether you are overweight or not.  The chances are that you will be very aware of how much effort you have put into developing your muscles and you will know there is no concern whatever your BMI might say.  For the rest of us, we cannot use this as an excuse!

Ok, that is enough for now.  I hope you found it useful.  Next time we will consider another measurement used in weight management.

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