BMI, mortality, weight stigma, science… sigh

Emily Nagoski
4 min readMar 16, 2021

Hey all, I really enjoy Health Care Triage, a video series on health-related issues that often includes the phrase “To the research!” — which is basically my life motto — so of course it’s, like, my fave. You should totally watch these takedowns about milk and vaccines not causing autism.

So I cringed a LOT when I realized I was going to write a blog post being critical about the newest video, on the relationship between BMI and health. It’s based on a giant new meta-analysis. Here is the research paper itself and here is the video:

So.

Look at the main overall graph of the relationship between mortality and BMI:

( from Global BMI, 216 )

The red arrow is pointing to the 22.5–25 BMI range. The bigger the square is, the more individuals are represented in that group. The longer the lines are, the more variability there is within the group. The scale at the bottom is 15 (at the axis), 20, 25, 30, 35, 40, and 45) :::

Notice that a BMI between 30–35 (the 7th square — remember 30 = “obese” according to the CDC) is lower risk than BMI under 18 (the first square).

Notice that a BMI between 25–30 (the 5th square — “overweight” according to the CDC) is lower risk than a BMI under 20 (the second square — within the “healthy” range).

And… that part in the video where Aaron sort of shrugs through a mention that there are differences for men and women? Here’s the graph of that “I guess I should mention…” dismissal:

WTF! High (and low) BMI is clearly much higher risk for men than for women! CLEARLY MUCH HIGHER.

And yet who gets more shit, not just from the media and from their cultural overall, but also from their doctors, about their weight?

Women (pdf). Twice as much as men.

Hence the student who was a competitive figure skater in high school — read: professional athlete — with body fat so low that she was skipping periods, yet her doctor told her she was “overweight,” because her BMI was high from all that professional-athlete muscle mass. Hence my own doctor who walked in, eyes on my chart, for our first (and only) appointment and told me I needed to lose 15 pounds. He had never even looked at me, much less at my blood sugar, blood pressure, resting heart rate, or any other actual measure of my health, and the first thing he said to me was that I was too fat.

Think thin privilege isn’t real? Ask Elna Baker:

Stigma against fat people only causes more negative health consequences, not least because doctors’ implicit bias against fat people (as well as people of color) and sexual minorities) reduces quality of care — really, fatphobia among medical providers is both common, surprisingly persistent, and unambiguously problematic — but empathy-building (PDF) and exposure to counter-stereotypes can reduce that bias. As is often true with implicit bias, doctors are not aware of their bias. Also male doctors are more likely than female doctors to have implicit bias against fat people.

Aaron: your video isn’t helping with this — and it could have.

You could have said, “Look! It’s actually WORSE to have a really low BMI than to have a somewhat high BMI! You can’t assume someone’s health status based on their weight!”

Or, “Look! This matters so much more for men than for women, and yet who gets more crap for it? Women! How unfair is that?”

Or, “Look! The range of ‘healthy weights’ isn’t where the government says it is! They say 18.5–24.9, but actually the population is better off 20–30!”

I wish you had said any of those other things, all of which are equally (if not more) supported by the meta-analysis, but which offer far more insight into the relationship of this piece of science to the cultural context that receives it. And I’m surprised that someone whose work is usually so good at integrating the evidence with the cultural context of that evidence — including corporate influence on government recommendations — would instead offer such a shallow, unhelpful analysis.

So for everybody else, let me just reiterate that the cultural thin ideal is a tool of patriarchal, capitalist oppression.

When you go to the doctor and they ask you to step on the scale, feel free to say, “I’d rather not.” That’s what I do.

And if they suggest “losing weight” as a strategy for treating whatever is wrong with you, feel free to say, “What behaviors are you recommending?” If you want to be snarky, you can say, “Should I have my arm removed… or my leg? Both of those would reduce my BMI.”

BMI is stupid.

Exercise is good for you.

Food should look something like it did when it was alive.

Stigma is toxic and our food infrastructure is FUBAR.

Okay.

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Emily Nagoski

sex educator, author, researcher, and activist. also: nerd. http://go.ted.com/emilynagoski and @emilynagoski