Why BMI is not a measure of health
Hey guys!
I’ve been MIA. Or, more like, missing by being incapacitated due to a back injury. A few weeks ago, I had a tweak in my back that I’m guessing came from power-lifting (my boyfriend says I “butt wink” in my squats). The tweak was painful, but manageable. I didn’t want to stop moving though, so I kept up with my morning walks and stair running and just decided to put a hold on power-lifting. This was dumb because the pain would just keep coming back, and some days worse than others. So, I decided to stop being overly ambitious and took a week off from any movement except for the absolute necessary stuff like driving to the office, going to the bathroom and making myself a meal. My back would feel better every day of non-movement. Then, last Saturday, I decided the tiny pain left in my back was tiny enough to work through. So, I decided to engage in household Olympics. You know, scrubbing the bathtub, etc. Next thing I knew, I could not stand. And this lasted for 2.5 days. I don’t even want to describe the pain and how I had to devise an elaborate way to use the restroom. Dear lord. I went to the doctor on Monday (my boyfriend had to practically carry me to the office) and she told me I had a muscle spasm, which she could easily find via the bruise I had given myself by rubbing that spot on my back. She gave me a high dosage of Ibuprofen and a muscle relaxer. The muscle relaxers don’t work and the Ibuprofen works just a bit. I can’t help but wonder if it’s more than a muscle spasm, but I’m also not obsessing about what it could be (ah, to be wiser from all those panic attacks).
It’s been a week since then and I’m just barely starting to feel better. I’m hoping I continue to get better but am also considering finding a physical therapist to ensure that I strengthen the area and also know what exactly is going on. We’ll see! Anyone out there suffered back injuries? Holla’!
Anyhow, in addition to telling all of you about the dangers of butt-winking
, I wanted to tell you about the reality of BMI. I talk a lot on here about what obesity really means and how the rhetorical abuses of the term may actually be harming us more than any weight-related “epidemic” and I’ve yet to really tell you about BMI, so I wanted to change that.

What is BMI?
BMI stands for Body Mass Index and it’s basically a ratio of a person’s height and weight. Specifically, BMI is the number that is generated after dividing someone’s weight in pounds by their height squared in inches and then multiplied by 703. A Belgian mathematician developed the ratio in 1832, noting that it should be used as a statistical generalization for large populations (in other words, not intended for individual use).
But what has it become? It’s become the ONE WAY that we measure overweight and obesity in this country. You know all those stats about how we’re all doomed to die in a fatpocalypse? They’re all based on this bogus measurement.
What are the cut-offs?

As you can see above, borrowed from Wikipedia, there are several categories for BMI – including the one we’re all meant to strive for: “normal” or “healthy weight.”
So, BMI is the way we measure obesity and overweight in this country EVEN THOUGH we do not have good reason to believe it measures health. Is this sad and detrimental to our health? Yes and I’ll explain why below.
So, uh, why did this bullshit measurement gain popularity?
The BMI’s popularity is due to a paper published in the July 1972 edition of Journal of Chronic Diseases by Ancel Keys, which, purportedly, found BMI to be a good proxy for body fat % among height-to-weight ratios. Keys, like the Beligan polymath who developed BMI, did not see at useful for individual cases. But, lo and behold, the National Institutes for Health (NIH) decided to use BMI as its measurement and, in 1998, a committee decided that they should lower the BMI cutoff for “ideal/normal” weight, which effectively made 25 million Americans “overweight, ” and thus “unhealthy,” overnight. You can read more about this in Julie Guthman’s book, Abigail Saguy’s book and Ragen’s blog. As Ragen notes, “3 members of the committee responsible for making the recommendation had direct ties to pharmaceuticals that manufactured diet pills for profit. A fourth member was the lead scientist for the program advisory committee of Weight Watchers International.” Did these Americans, in fact, go from healthy to unhealthy overnight? That’s not as easy to answer as you might suspect. While I want to say, “of course not!” in my smart-ass voice, I also know the power of persuasion and stigma to have strong effects of people. In other words, if you are told, overnight, that you became sickly and unhealthy – will you believe it?
What BMI is not:
- a measure of health
- a measure of worth
So…what’s the problem?
- BMI has no causal relationship to a person’s health! In fact, there are studies that show those who are overweight tend to have LOWER mortality than those who are normal- and underweight!
- BMI has become something that is considered SO important (read: profitable), students are now being sent home with “BMI report cards” showing where they stand on this measurement
- BMI has become something so important (read: profitable) our government has waged a war to get people to lose enough weight to become “normal” on the BMI chart. Unfortunately, we view weight in this country as something that can be easily fixed (the weight loss industry is, after all, a $6B industry!). You won’t see anyone telling you that you can change your HEIGHT (though, I imagine this will occur soon enough with the latest eugenics-like invention that will sure enough come to market when weight loss “cures” stop selling).
- BMI has become something so important (read: profitable) that local states, govt agencies and employers are encouraging citizens to lose body weight (i.e. points from their BMI). For instance, “MI Healthier Tomorrow” is a communications initiative of the Michigan Health and Wellness 4 x 4 Plan that is designed to encourage Michiganders to lose 10 percent of their body weight. How wonderful! >:(
- When the media discusses the obesity “epidemic,” it often uses footage of “headless fatties” – in other words, they typically use footage of very large persons’ bodies to show us the extreme cases of obesity (BMI) and to remove us from feeling implicated in this crisis. The truth is – most of us ARE indeed a part of this crisis! Brad Pitt and Will Smith are overweight based on BMI. Should we incentivize them to lose 10% of their body weight? I am overweight. Yes, by 1 pound, but, alas, I am implicated in this crisis by virtue of having a healthy no-longer-bulimic body.
- We are so obsessed with weight and weight loss that we have sacrificed our health and many of us, including medical doctors, are under dangerous assumptions about what health “looks like” and weighs. This affects people who are thin and malnourished but fall in the “normal” BMI range as they are often assumed to be healthy and engaging in healthful behaviors. Alternately, people who are overweight (per BMI) and in good health and engaging in healthful behaviors may be told they need to lose weight. Do you see the insidious nature of this weight obsession? Even those who are healthy may be told to engage in dangerous and unhealthful practices simply because they land in the overweight category, which the zeitgeist believes is bad even when science shows us that it tends to be more predictive of health!
So, remember, this entire CRISIS hinges on some bullshit measurement of weight-height ratio that is NOT a measurement of health. And, remember, all of us with bodies are implicated in this EPIDEMIC. You never know, tomorrow the NIH can decide that “normal BMI” should actually be dropped a couple points and, overnight, YOU can be a diseased drain on society.
<3,
The Cranky One
Tags: BMI report cards, body mass index, dr. abigail saguy, Julie Guthman, obesity politics



8 People have left comments on this post
I totally agree, BMI is useless for measuring ones health. People have very different body structures and should not be measured by BMI.
I can sympathize with your back pain. I injured my back after helping a family member move house back in Oct 12th 2012 and it is still bad. I get lower back pain (bearable) whenever I walk more than 200 yards. However, later that day the pain seams to radiate up my spine and I often find tasks like doing the washing up a nightmare as I often double over in pain. I think it is about time I see a doctor..lol.
Hope you feel/get better soon.
Claire
I’m sharing this with everyone I know.
But especially the doctor who’s triggered my old problem. I’m just glad I realized it BEFORE spending a chunk of money on “diet aids” again.
Keep in mind that BMI is just another number and of course it doesn’t show your health measure. I am not a doctor but i know for a fact that people have diferent bone density and that could severely alter the BMI number.Anyway I don’t know if i am wrong, but if I am, please be free to correct me
I can’t stand it. This article is great because it exposes the truth about how the BMI is set up to screw people out of being healthy, and encourage them to look to someone else to give them what they need to get healthy. Another reason to believe that the majority of what the media and politicians say is garbage. Tragic…
If BMI is a ratio of a persons height and weight, it is obviously inaccurate. People have different body types as well different speeds of metabolism.
I cannot agree with this more! This BMI has no evidence based medicine behind it. People are different, and some very thin people have problems because they have eating disorders and are not getting enough nutrients. I personally look at my own body fat measure to set weight targets, but that is for my own benefit in terms of aesthetics. I do not believe on starving oneself or sacrificing nutrition to keep the body fat down. I saw a study recently that showed Americans are actually gaining more weight, despite consuming less calories, probably because they are following the advice of fad diets and killing their metabolism.
Hi
As far as I can see BMI would be more representative if we all had the same make up but as we don’t and some people are built lighter and vies versa. This only leaves a small amount right in the middle of the pack that it is measuring to any accuracy. As for a health index I really cannot see what relevance it has at all. It measures your body mass index and nothing else and as we know this is only one of a huge amount of factors that go towards how healthy we are. It just works for the politicians so that they can push their opinions and policies on to the public.
Great post thanks lee