We’re finally on the other side of 2020! And with the new year comes the same old-school messaging: “Isn’t time for you to set a new year’s resolution, and shouldn’t you start the new year by trying to lose weight?” This is the time of year when we’re all lambasted with diet- and exercise-focused imagery and told that we should set a weight loss goal.
Here’s the thing: we know based on the science that weight bias and stigma like that can actually be harmful for your mental AND physical health. We’re here to encourage you to set meaningful, specific, health-based goals for this year if that is what you want and need – but we’re also here to remind you that your weight doesn’t dictate your health status. This post is all about digging into the history of BMI, our major measurement of weight and body size in this country, and why it isn’t the best measure of health.
The History of the BMI
Do you know the equation for BMI? It’s our mass in meters over height squared. Basically, this translate to a measure of your overall mass relative to your height. It doesn’t give a sense of body composition (like how much body fat you have relative to bones and muscle), nor does it give any information about how healthy you are inside of that body – it’s just a number about your mass.
How did the BMI come to exist? It was created over 200 years ago by Adolphe Quetelet – a Belgian astronomer and mathematician, not a physician – who wanted to quantify “the average man.” The formula was developed based on measurements of Scottish and French people, so it was only developed with white Western European people in mind. Weight and BMI weren’t considered measures of health until U.S. life insurance companies started tracking and using BMI to influence coverage and cost in the early 1900s. Using BMI to quantify health status was solidified by the work of Ancel Keys in the 1970s, at which point he conducted studies on a majority white sample of men. Current research has shown that BMI only accurately describes body fat (not to mention health status) in about 50% of women – this is largely due to the formula being based on men’s measurements in the 19th century.
Limitations of the BMI
- It doesn’t account for differences in body composition. As we mentioned above, BMI doesn’t accurately describe the ratio between lean and fat mass. The classic example is the body builder with 2% body fat with an obese BMI – it just doesn’t work for that subpopulation, as it doesn’t work for many others.
- It doesn’t incorporate better, more evidence–based measures of health on the inside. There are many people walking around with very healthy measures of risk for all kinds of chronic diseases – heart disease, neurological disease, and even mental health – with high BMI. Being healthy and having a high BMI can co-exist.
- It’s even less accurate for certain people. The BMI was designed for use/characterization of Western European adults, so it’s no surprise that it doesn’t accurately describe large subgroups of people: Black people, Hispanic or LatinX people, elderly people, women, and tall people to start. With limitations like that, it’s tough to use this as a population-wide indicator, right?
These are just a couple reasons why we and many other clinicians are moving away from focusing so much on BMI and body weight. Knowing this information and being able to advocate for yourself is a big step in the journey toward healing your relationship with your body.
So, What Do We Do?
The good news is that the solution is pretty simple: stop paying attention to the BMI and start paying attention to other indicators of mental and physical health. As naturopathic physicians, we are trained to identify and address the root cause of disease and discomfort – this is never going to be simply someone’s weight or BMI. Ask your doctor (including your ND!) to focus more on other indicators of health first to preserve your self-esteem and other aspects of mental health. Focus on wellbeing rather than symptom management. Ask yourself, regularly:
- How do I feel right now in my body?
- How do I want to feel, and how can I get there?
- Is my weight holding me back from doing things I love and living the life I want to live?
BMI isn’t a reason to put life on pause. If you’re looking to maximize your health and wellness without fear of body shaming, diet prescribing, or weight loss talk, working with a member of the Northwest Integrative Medicine Body Positive Medicine team is one way to do so.
Big virtual hugs,
Dr. Pickworth & Dr. Corn
- Huistra HM. De geschiedenis van de BMI [History of the BMI]. Ned Tijdschr Geneeskd. 2017;161:D1242. Dutch. PMID: 29303085.
- Rothman KJ. BMI-related errors in the measurement of obesity. Int J Obes (Lond). 2008 Aug;32 Suppl 3:S56-9. doi: 10.1038/ijo.2008.87. PMID: 18695655.