The WHOLE BMI formula is completely and totally flawed/false in every, any and all applications regardles of child, adolescent, youth, young adult, adult. The factor of squaring the height has zilch/no science behind it at all. It just something plucked out of the sky by the inventor of the BMI formula back in the mid 1800's to make the formula kind of fit a whole of population calculation back in the 1800's. The inventer of the BMI never meant it to apply to indiviual people and it was never designed to be used to measure any one individual person.
Here are words from the above post by Charlotte Bevan (dec) the C in the C & M ED Productions piece posted by toothfairy
There are a couple of problems I have with the whole weight obsession thing. I really think I don't know have to go on another rant about BMI but, just in case anyone missed my last million rants, BMI was never ever ever ever ever ever meant to be used to by clinicians as a measure of physical or mental health. EVER. It is a population screen that is full of false positives and false negatives, not a clinical tool and, quite frankly, should not be being used by clinicians.
If you have a clinician who is calculating your child's mental and physical health based on BMI, they are using the wrong diagnostic tool
The body mass index (BMI), or Quetelet index, is a heuristic proxy for human body fat based on an individual's weight and height. BMI does not actually measure the percentage of body fat.
BMI was explicitly cited by Keys as being appropriate for population studies, and inappropriate for individual diagnosis.
BMI has been used by the WHO as the standard for recording obesity statistics since the early 1980s. In the United States, BMI is also used as a measure of underweight, owing to advocacy on behalf of those suffering with eating disorders, such as anorexia nervosa and bulimia nervosa.
BMI can be calculated quickly and without expensive equipment. However, BMI categories do not take into account many factors such as frame size and muscularity. The categories also fail to account for varying proportions of fat, bone, cartilage, water weight, and more.
Despite this, BMI categories are regularly regarded as a satisfactory tool for measuring whether sedentary individuals are "underweight", "overweight" or "obese" with various exemptions, such as: athletes, children, the elderly, and the infirm.
One basic problem, especially in athletes, is that muscle weight contributes to BMI. Some professional athletes would be "overweight" or "obese" according to their BMI, despite them carrying little fat, unless the number at which they are considered "overweight" or "obese" is adjusted upward in some modified version of the calculation. In children and the elderly, differences in bone density and, thus, in the proportion of bone to total weight can mean the number at which these people are considered underweight should be adjusted downward.
The medical establishment has generally acknowledged some major shortcomings of BMI. Because the BMI formula depends only upon weight and height, its assumptions about the distribution between lean mass and adipose tissue are not always exact. BMI sometimes overestimates adiposity on those with more lean body mass (e.g., athletes) while greatly under-estimating excess adiposity on those with less lean body mass. A study in June, 2008 by Romero-Corral et al. examined 13,601 subjects from the United States' Third National Health and Nutrition Examination Survey (NHANES III) and found that BMI-defined obesity was present in 21% of men and 31% of women. Using body fat percentages (BF%), however, BF%-defined obesity was found in 50% of men and 62% of women. While BMI-defined obesity showed high specificity (95% of men and 99% of women presenting BMI-defined obesity also presented BF%-defined obesity), BMI showed poor sensitivity (BMI only identified 36% of the men and 49% of the women who presented BF%-defined obesity).
Secondly, weighing is a cultural thing. Here, in the UK and in Australia and NZ, we are not weighed every time we visit the doctors. For medical purposes, I was weighed prior to Georgie being born (March 1997) and then not again, until July 2010 just before my breast cancer operation
and this one
OK I caved and did some searching for some old BMI rants.
First - from the film State not weight film (as approved by Professor Treasure)
Promised BMI rant
But, as a general rule, isn't BMI used as a recovery indicator? I am particularly thinking of the 18.5 BMI of the diagnostic criteria.
Good question, Sue. BMI is not an accurate measure, as BMI ranges contain both false positives and false negatives. Giving an exact number BMI is a nonsense really. Each patient is different and requires a different weight to recover. Also neither buleemia or Ednos have a BMI diagnostic criteria. It is only used for anorexia and only as a diagnostic criteria, not as a indicator of recovery. The focus on BMI has distracted clinicians from the real process of recovery. Wayt is only part of recovery.
Right. I thought that the healthy weight range for BMI started at 18.5
You are right , Sue. The WHO's minimum healthy BMI is, indeed, 18.5. However, you should bear in mind, that this is the level at which the diagnositic criteria has been set for a diagnosis of anorexia. It should not be confused with an indication of recovery. Remember, Just because an eating disorder sufferer attains a BMI of over 18.5, it is not a recovery indicator. There are very few people, who are healthy, at that BMI level. They tend to be people, who are exceptionally lean and fit, say, a marathon runner. The average, healthy, BMI range is higher. That is the healthy weight range, for the majority of the population. However, eating disorder patients are not average. For example, there are some anorexia patients, who need to keep their BMI at 24, or above, in order for the anorexia symptoms, not to reoccur. There are some buleemia patients, who need to keep their BMI at 25 or above, in order to be at optimum function.
The 18.5 BMI criteria is being dropped from the D S M 5. I suspect, because of the rigidity of a set number. There are plenty of eating disorder patients, who are critically, and lethally ill, at a much higher BMI. BMI is, at best, a population screen and not an accurate mathematical formula - remember all those false positives and false negatives. These are just numbers, Sue, and quite meaningless in recovery. Recovery is not about numbers. There are so many factors inverwoven with the weight issue. You are aiming for a state of mental health rather than a recovery weight
Right. You are saying, that there is no correct BMI, for a patient. That in fact, BMI is not a measure of the patient's recovery or mental health. You are also saying, that the W H Os figure of BMI 18.5, is a diagnostic criteria for anorexia, not a recovery indicator. That the BMI 18.5 is being dropped from the new DSM 5. That Recovery is not about numbers on a scale as there are so many other factors interwoven
Mother, wife, farmer, C of C and M Productions