Hello Dazzle! Thanks for coming and hanging out with me today, I’m glad that you are here. Today I want to talk about the reasons that BMI shouldn’t be used clinically and should not be part of your weight management plan. BMI stands for Body Mass Index. This value is a number that is derived from a person’s weight and height. The only reason that it is currently being used is because it is a convenient number rather then being a measure that holds any meaning or value. I’m not the first to write on this topic [1] [2] [3] [4] and I am far from the only medical professional declaring that the use of this measure needs to stop. [5] [7] [13]
Let’s start off with the fact that the BMI has no medical foundation upon which to stand. It was not developed by a medical professional with any medical research to explain or justify its use as a medical measure. The BMI was created in the 1830, about 200 years ago. It was not created with measuring obesity in mind, but rather as a means to discover what was the average man. Nothing in this research measured anything about the person’s health. It was looking only at their height and weight in relation to each other. Nothing more then that. Lambert Adolphe Jacques Quetelet, the person who developed the BMI, even stated it couldn’t be used to determine a person’s fatness. [4] [7]
The next thing to point out is that the math that creates this formula doesn’t make any sense. The mathematician that created this formula couldn’t get the data to line up into any kind of neat fashion, so he invented a formula that made it work. Generating someone’s BMI requires you to square their height. There is no logical reason that this would be required if their was a correlation between a person’s height and weight. The truth is that this was the only way that the mathematician could get the numbers to work. Since the data wasn’t giving him what he was looking for, he invented a formula that did. This is the definition of bad science.
The BMI does not take into account where the person’s weight is coming from. Bone and muscle weigh more then fat. This means that if a person has strong, healthy bones and good muscle mass they will weigh more. Those who are in this healthy category are often measured as having high BMIs that indicate that they are obese. This fact alone means that the BMI is fundamentally flawed and cannot be trusted as an accurate measurement for a person’s fat ratios. “It should be noted that in population-based studies women generally have a BMI that is lower than that in men, even though their fat mass relative to their body build or BMI is considerably greater.” [7] [8] [9] [10] [11] [12]
We have long established the reality that mathematical averages do not represent an individual in any kind of accurate fashion. Data averages lead us to information that cannot possibly be applied to an individual with the classic example being that of having 2.4 children. There is a great deal of research that has gone into the proper way to evaluate data for the applicability to individuals. None of those considerations are take into account when generating the BMI. [6]
One of the major problems with the averages that BMI represents is that it mathematically assumes that tall people are simply scaled up versions of short people. This is simply not the case. Those who are taller also tend to be thinner and of a slighter build when compared to those that are shorter. The body ratios between tall and short people simply do not equate to each other. [7]
The BMI data collected will always be skewed and not represent the actual population presentation. This is recognized as being a factor of significantly lower BMIs not being compatible with life and those individuals not being included within the data. These means that the BMI charts skew to the higher end because they don’t fully capture the population. This means that what is presented as being an average BMI isn’t actually the average BMI. [7]
The human body is complex and nothing about it has ever lent itself to such a simplification. Our weight and risk for disease is no different. There is research that demonstrates that those who are shorter have a higher mortality rate when compared to taller people with the same BMI. But this isn’t something talked about in the medical field and it isn’t addressed within the BMI model. [7]
The medical field has taken the BMI and has generated categories based upon these numbers that are complete nonsense. It suggests that there are clear and distinct categories between being over weight and a healthy weight. There is no research to support these categories, yet we are using them to determine the medical advice and medical care that we are providing patients. Additionally, the research has shown that many of the people that fall into the obese category are actually within the average for the population bell curve given the same mathematical standards. [7]
More recent research has shown that BMI is not an a risk factor for cardiovascular disease or death related to heart health. This is just another indicator that using BMI to determine a person’s over all health isn’t clinically valid. [13] Most researching heart health consider this lack of correlation to be an issue with the BMIs inability to accurately measure the fat present in a person’s body, let alone where that fat is being deposited. Since the risk associated with heart health is having fat on your organs, it is not surprising that there is no correlation between a person’s BMI and their heart health.
This is an unethical and discriminatory practice. Looking at the language of the categorization alone can reveal the manner in which people being under weight is preferred over those being over weight. Those who are in the category above normal are labeled as being “pre-obese” despite there being no research to indicate that their weight predisposes them to becoming obese later. Yet those in the category just below normal are labeled as “under weight” rather then “pre-normal.” This highlights the way medicine has pathologized higher weights in a way it hasn’t for lower weights. [7]
It clearly isn’t working. We have been using BMI as a means to measure, categorize and guide treatment for weight management. We are also using the BMI to guide decisions regarding public health policy. Yet, America remains the leader in the rates of obesity in the world. This approach to evaluating and treating obesity isn’t working and it doesn’t make sense to keep a system that isn’t producing the desired outcome.
Well, that’s about it for my rambling today. Thanks for coming and spending some time with me. If you like what you read, click on that like button. It really does help! Until we talk again, you take care of yourselves!
Additional Reading and References
- The really old, racist and non-medical origins of the BMI
- The Bizarre and Racist History of the BMI
- The Problem with BMI
- Top 10 Reasons Why The BMI Is Bogus
- The History of BMI: Part One
- Populations and samples
- Body Mass Index
- Age changes in body composition revealed by computed tomography
- Arm and leg composition determined by computed tomography in young and elderly men
- Body mass index and percent body fat: a meta analysis among different ethnic groups
- A requiem for BMI in the clinical setting
- BMI-related errors in the measurement of obesity
- Is BMI the best measure of obesity?
- Should we continue to use BMI as a cardiovascular risk factor?
- Beyond BMI: The value of more accurate measures of fatness and obesity in social science research
- In BMI we trust: reframing the body mass index as a measure of health
Zebra Pig 