Are BMI Scales an Accurate Representation of Health?

Disclaimer: This blog is intended for educational purposes only and is not to be used as professional or medical advice. The content in this blog may be triggering as it includes sensitive material including terms such as weight and obe*ity, and the topic of discrimination based off of weight.

Have you ever calculated your body mass index (BMI) to determine your health or ever wondered why BMI is used? If so, how did this make you feel? 

I’ve had my personal share of years being controlled by my weight or what that calculated as on the BMI scale. In my most disordered and harmful days of my life when I was my smallest size, I STILL wasn’t “normal” based on the BMI scale. 

That’s such a harsh reality for those of us who have pursued that number that just doesn’t end up being “good enough”. But what is often missed here… I was never actually healthy at that lower weight, despite what society might think. 

So what does that tell us?

After thorough research, I learned more about the number I was once so perturbed by. I learned what it means, where it came from (which is a huge shocker to most), and how it came about in affecting our health. Hint: It’s not your weight. 

This blog was co-authored with a dietetics practice student, Samantha Matte, and myself. This blog will answer many questions you might have about the BMI in relation to health. Needless to say, there’s so much more to it than meets the eye (pun intended 😉 ). 

BMI, Where Did It Come From?

According to a Critical Review of BMI, it was originally developed by an Astronomer and Statistician, Lambert Adolphe Jacque Quetelet. His goal was to establish the “social average” through determining characteristics of “the average man”. However, the participants used in this research were:   

  • Caucasian 
  • All men 
  • Between the ages of 18-55
  • Not too muscular  

This technique is an extremely old-fashioned method of determining the population’s health. It dates back 200 years and is not inclusive.

Moreover, each BMI category has been altered over the years and changed drastically in the late 1990’s

After the World Health Organization published their updated classification of the BMI categories, almost half of the population went from being considered a “normal” weight to being classified as “overweight”. This change was driven by the pharmaceutical industry – the only company that was selling weight loss drugs.

Question of their interest: How much profit would be made just by classifying more people as “overweight” or “obese”, overnight?

What is BMI and how is it calculated?

BMI is our body’s mass (weight in kg) divided by height (m squared).  

Currently, it is used within the healthcare system as a screening tool. It supposedly assesses a patient’s potential disease outcome and risk of death. In short, BMI is a very simplistic tool used to classify individuals as underweight, normal weight, overweight or obese. 

But does it actually do that? 

Why BMI is Flawed

Firstly, it’s only pointing at correlation – NOT CAUSATION. For example, someone’s weight being related to a disease, could be just as probable as their weight being related to genetics, access to food or healthcare. 

In other words, BMI doesn’t mean that your weight CAUSED a certain disease. 

Moreover, if weight was a direct and mutually exclusive cause, it would mean that someone in a smaller body couldn’t get a certain disease. However, there isn’t a disease that ONLY affects those in larger bodies. 

Secondly, the correlation between BMI and risk of mortality doesn’t consider important factors like: 

  • Genetics 
  • Mental health 
  • Metabolism
  • Eating disorders 
  • Socio-economic status and 
  • Behavioural factors like physical activity level, alcohol consumption, diet, smoking or drug use.

Additionally, since BMI is based on Caucasian males of ages 18-55 who are not muscular… it is therefore not accurate the rest of the population and will be skewed based on: 

  • Age (it misrepresents infants, children and the elderly)
  • Gender
  • Ethnicity
  • Pregnancy
  • Lean body mass (also known as muscle mass) – since muscle weighs more than fat!

Does a Higher BMI Cause Us to be Unhealthy?

According to studies, body mass is a very weak predictor of death. Furthermore, they also suggest that a larger than “normal” BMI might actually be protective among the elderly. 

It is suggested that a higher weight among elderly populations may be protective, since increased fat tissue can cushion them from the impact of falls. Falls can be very impactful because bones get weaker with age. Consequently, a serious fall can significantly impact an elderly person as it may take off 3-10 years of their life depending on the fall. 

Thus, the answer to this question is no, a higher BMI does not cause us to be unhealthy. You can be healthy in a larger than “normal” sized body. BMI is NOT a direct indicator of your health or risk of death. For instance, you can eat fruits, vegetables, whole grains, exercise regularly, have great blood work results, AND have a higher weight than the “normal” or “ideal” size. 

So, if the only reason you want to lose weight is to be healthy – know that you can achieve health in many ways other than focusing on weight loss. 

Weight Stigma & Discrimination Based on Size

Did you know that more than half of 2400 patients in a study reported receiving inappropriate comments about their weight?

Weight stigma, by definition, is negative judgment towards those who are of a higher weight than what is considered “normal”, thin or attractive. Typical assumptions made with weight stigma are that those in larger bodies are lazy, unintelligent, or lack self discipline. 

Unfortunately, from time to time, even some healthcare professionals (such as doctors, nurses and more) stereotype those in larger bodies. This weight stigma may show up as having healthcare professionals blame weight for your symptoms or any health-related concern you bring up. As a result, you may feel the need to advocate for yourself and your health… over and over again. 

If this is you… I feel you. It can be really exhausting and overwhelming. Know that your ACCESS to Healthcare with RESPECT and DIGNITY is a human right!

If you feel empowered to advocate for yourself, start by asking not to be weighed, or get a blind weight. And when you get “weight loss” as the only solution to your health issue, ask the doctor: “What else would you suggest for a thin patient?” or “What is the evidence around weight loss in helping this issue?”

On the other hand, if you are finding it hard to advocate for yourself, reach out to a healthcare professional who practices from a Health at Every Size ® approach, like myself.

Healthcare professionals need to be held accountable. Above all, you deserve ethical support for your health!

Impact of Weight Stigma

Let’s get real … The impact of weight stigma (or fatphobia) is MUCH WORSE for your health than a piece of bread or cake. 

Weight stigma poses extreme risk to one’s health and may lead to: 

  • Depression
  • Low-self esteem
  • Poor body image 
  • Anxiety 
  • Stress 
  • Disordered eating or the possibility of eating disorders

The stress caused by the experience of weight stigma and obsessing about food and weight IS MORE HARMFUL than the number on the scale itself.  

These risks carry forth into every aspect of your life. They can impact your relationship with yourself, your relationship with others, and your relationship with food. And in turn, all of that can negatively impact your overall health. 

Alright, so if not weight loss… then what?!

First, reject the diet culture and diet mentality.

Second, accept your body as it is today so that you can move forward.

  • Know that your body transforms naturally and no matter what you do today, it will not be what it used to be. Accepting your body doesn’t mean you’re giving up on yourself. On the contrary… you’re giving yourself a fighting chance to live with more freedom & peace! To read more about this, check out the “ Radical Acceptance” blog. 

Third, your mental health MATTERS.

  • If pursuing weight loss all these years has gotten you into deep depression, anxiety, low self-esteem, cycles of restriction, bingeing, guilt and shame…. Then you need to break the cycle. Start by exploring ways in which you can improve your mental health around how you feel about your body. To learn more about your relationship with food and your body, check out the blog, “ How to start loving your size and yourself today”.

Fourth, advocate for yourself with the healthcare professionals you are seeing.

  • If you are told to “lose weight” for everything you see the doctor for, ask them: “How would you treat this if I was in a smaller body?”.
  • Alternatively, let your doctor know that pursuing weight loss only leads to weight gain for you. Ask for other treatment options available.
  • If the number on the scale triggers you and might throw you in a negative loop, ask to not be weighed, or get a blind weight (facing away from the scale and not being told the number).

Lastly, look for help from those who are weight inclusive or work from the Health At Every Size ® to assist.

This topic is so dear to my heart. I wholeheartedly believe that ALL individuals, no matter their size or what they look like, should be treated with respect and dignity both within the healthcare system and society.  

No matter where you are in your journey today, know that you deserve to heal. 5 years from now, you’ll be thankful you started today. Don’t wait until something else changes. You deserve better!

Do you always struggle with your body image, size and shape?

Want to rid yourself of self-judgment, guilt, and shame? Let’s chat. 

Book your 15-minute call here for us to chat and see how I can help you!

Blog Author: Samantha Matte, Dietetics Student at Brescia University College

Blog Contributor: Yasmin Alachkar, Dietetics Student at University of British Columbia

Edited & Approved by: Cristel Moubarak, RD


Harvard Health Publishing Harvard Medical School: How Useful is the Body Mass Index (BMI)? (accessed November 27 2020) Available from:

Frank Nuttall MD, PhD: Body Mass INdex Obesity, BMI, and Health, A Critical Review (accessed November 27 2020) Available from:,_bmi,_and_health__a.5.aspx

UC Santa Barbara: Flaws n Body Mass Index (accessed November 27 2020) Available from:

American Journal of Clinical Nutrition: BMI and all-cause mortality in older adults: a meta- analysis (accessed November 27 2020)  Available from:

International Journal of Epidemiology: The Epidemiology of Overweight And Obesity (accessed November 27 2020) Available from:

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