Why BMI Is Completely Bullshit

If you’ve ever been to the doctor, it’s more than likely that your BMI has been discussed. For those of you who don’t know, BMI stands for Body Mass Index. And I’m here to tell you it’s utter bullshit. 

The body mass index is a calculation of kg/m2or, to put it simply, body mass divided by our height, and then squared. The problem with such measurement is that it doesn’t differentiate between fat and muscle. There are four categories this arbitrary number can place you in: 

  1. Underweight (BMI of 18.5 or below)
  2. Normal (18.5 to 25)
  3. Overweight (25 to 30)
  4. Obese (30 and up)

How did we get this ridiculous calculation?

A Belgian mathematician, Adolphe Quetelet, wanted to understand the science behind statistics. For instance, he noticed an increase in crime in poverty-stricken areas. He called his research “social physics.” Quetelet created a simple formula for body mass in order to assist governments and their resource allocations per population. He didn’t create it for medical purposes and even spoke out against using it for measuring health. If the creator of the formula didn’t want it used for such a purpose, what happened then? In 1972, American physiologist Ancel Keys started using it as a measurement for obesity. 

According to CDC, 71.6% of Americans over the age of 20 are considered overweight. On top of that, 39.8% are considered obese. Essentially, when using BMI as a measurement, most of America is fat. However, how does the BMI factor in deciding the difference between 25 pounds of fat and 25 pounds of muscle? 

Oh wait, it doesn’t!

It’s an inaccurate tool, and inaccuracy has no place in medicine or science. There are many other ways to tell patients that they need to lose weight. If indeed they need to. And calling someone fat is definitely not the way to go. 

Shame doesn’t lead to change.

What does, however, lead to change is body positivity. It is a movement that has been sparking important conversations right now. It believes that human beings should have a positive body image. Fat or thin, body-positive advocates believe you should be allowed to love your body as it is. Unfortunately, there are many opponents who claim that our self-love is leading to an obesity epidemic. They also claim that because we accept ourselves, we’re glorifying being fat.

First of all, weight is not synonymous with health. Personally, I have suffered from disordered eating since my teens and I destroyed my body, all in the name of being thin. And I wasn’t doing it for my doctor. I was doing it to look the way Sports Illustrated told me I needed to look in a swimsuit. Thin does not equal healthy. Fat does not equal unhealthy. 

Armed with their bullshit concern, online trollers claim accepting ourselves is killing us. Nah, what’s killing us is diet culture. Heart disease and obesity are constantly linked to each other in the media. Wanna know a secret? Weight cycling, AKA yo-yo dieting, causes severe inflammation, especially over long periods of time. Later on, that inflammation is a risk factor for heart disease. We can argue correlation equals causation all day, but it doesn’t. When murder rates increase, so do ice cream sales — but no one is saying Ted Bundy is the Good Humor Man. Correlation does not equal causation. 

We want to vilify fat. But what we need to remember is that fat doesn’t kill. Depression caused by weight stigmas, however, can kill. Weight discrimination by health providers can kill. My BMI tells me I’m in the obese category. I have fluctuated a lot due to my fucked up relationship with food. Millions of people have. And yet, we still ignore the classism and ableism that corresponds to being an “ideal” weight. 

BMI is bullshit. 

Society’s beauty ideal changes every decade. 

Women’s bodies become trends. And trends come and go. 

If you’re fat, you’re viewed as having failed morally. 

I’m done. I’ve been done for a long time. I’m not playing this lethal game anymore. My body is my body. And whether it’s fat or thin or in between, that’s my business. An arbitrary number from a 150-year-old cisgender white guy will no longer determine my health and my worth. 

I am worthy. 

You are worthy. So, go live your life on your terms.

Featured image via Pexels


  1. The way you have provided detailed tips, opinions, and discussions about Body Mass Index and the guidance you provided, it’s imperative. Reading this post will make everyone feel better about “Body Mass Index”…

  2. I agree with Mac- pathetic! Yes, BMI is bullshit, especially as it doesn’t differential between male/female or muscle/fat.

    Perhaps the person who wrote this article is a ‘transformer’??

    It’s a pity Adolphe wasn’t a black lesbian, eh? / -:

  3. I am pleased to see more folks calling out how failed BMI is as measure of health as it’s use does have serious consequences.
    Personally I am built more heavily than the “average” man being I am large boned (10″ wrists) and have heavy muscular legs (26″ thighs). At my current 6′ / 250 lbs according to my latest physical I am level 2 obese an have a 1:5 chance of a stroke or heart attack according to my doctor. As such she pressed me to start taking several medications.
    Facts are when I was training for a marathon a number of years back I was running 40 miles/week and was tested at 8% body fat. At the then 205 lbs I was about 10 lbs over the top weight for someone my height. Not matter that I had a 35″ waist at the time I would be considered in need of losing at least 10 lbs according to BMI.
    Fast forward to a few years back having done a good bit of weight training my “trim” weight is now about 235 (36″ waist) but would be considered significantly over weight per BMI. At my current weight I do need to shed about 15 lbs but am hardly obese.
    None of this would matter a bit except that the medical field is still using this as a legitimate measure of health and as a basis for recommending medications. This antiquated “tool” either needs updating to allow for body frame size and perhaps waist measurement or thrown in the dustbin of outdated ideas.

  4. Love this post. I’ve hated the BMI BS for years. It says I should be between 107-142 or something ridiculous. I’d love for the medical world to stop labeling and treating people on whether they are thin or obese. Thin people die everyday. “Obese” people can live long lives. And individually we can start to look at ourselves as instruments instead of ornaments. We are enough and deserve medical care and attention just as we are.


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