5 Reasons Why the BMI is BS

Body Mass Index (BMI) is a simple (but bullshit) calculation that originally sought to track health risk among the US population. However, as you will read more about in the 5 reasons why the BMI is BS below, this calculation is fatally flawed for many reasons and is not in any way a viable way of tracking health risk in any population (or individual for that matter).

1. BMI is not a good indicator of health

The BMI calculation includes only weight and height as variables. It does not account for mental health, stress levels, physical activity, genes, environment, relationships, socioeconomic status, career satisfaction or financial security. However, all of these are important factors in determining an individual’s health.

According to this reputable study, “using the blood pressure, triglyceride, cholesterol, glucose, insulin resistance and C-reactive protein data, population frequencies/percentages of metabolically healthy versus unhealthy individuals were stratified by BMI. Nearly half of overweight individuals, 29% of obese individuals and even 16% of obesity type 2/3 individuals were metabolically healthy. Moreover, over 30% of normal weight individuals were cardiometabolically unhealthy. Using BMI categories as the main indicator of health, an estimated 74,936,678 US adults are misclassified as cardiometabolically unhealthy or cardiometabolically healthy.”

I relate so deeply with the statistics above. Doctor’s told me my BMI was “perfectly healthy” when I was in the throes of anorexia. They completely missed the mark as I was severely malnourished and in VERY poor health.

Additionally, those who attempt to intentionally lose weight (per a doctor’s recommendation based off their BMI) can actually increase their mortality risk according to the same study.

2. BMI is discriminatory in nature

First off, BMI fails to account for diversity among individuals (sex, age, ethnicity, etc). Even worse, insurance companies and medical providers refuse coverage based on BMI, a fatally flawed calculation. This in and of itself is discrimination and oppression. All individuals, regardless of their body size and shape, deserve equal and fair medical treatment.

3. BMI can lead to a host of negative mental and physical health issues including poor body image and eating disorders

BMI is just another way for diet culture to stigmatize those in larger bodies and celebrate those in thinner bodies. This leads to ethical consequences. When an individual is pathologized as good or bad based on BMI or weight, they tend to engage in destructive dieting behaviors. These behaviors set them up for a lifetime of struggle (including poor body image and greater risk of developing an eating disorder).

4. BMI is a money making scheme for the diet industry

According to this study, the weight loss industry is worth almost $60 billion per year. How crazy is that? One of the tools the diet industry uses is BMI (especially because it’s cheap and easy). Diet culture exists on the premise that your body is “not okay” and that is needs to be “fixed”. If we all felt great about our bodies, we wouldn’t spend money on dieting. They need us to feel bad about ourselves in order to make a profit. So twisted.

5. BMI is outdated

Adolphe Quetelet, a mathematician and astronomer (not a doctor), developed BMI in the 1830s (over 190 years ago). Additionally, this was a time when our knowledge of the body was very limited. Even Adolphe was explicit that it was not appropriate for use in individual health evaluation. Given the evidence above though, it’s also really not a viable indicator of a population’s health risk either.