Why BMI Is a Racist System

[easypeasylemonn]

So for a while, I've been trying to lose weight and I have always been "obese" according to BMI when I was size 10 due to my height. I now have a better grip on when I am my healthiest/how to lose fat in a healthy way (diet/working out).

I don't know if this has ever been raised before on Mumsnet but I find it crazy that people still don't know that BMI was developed using flawed, Eurocentric data and applied universally without considering differences in body composition. I've pulled some info together - what are your thoughts??

BMI Was Created Using White European Data:

Developed in the 19th century by Adolphe Quetelet, BMI was based on measurements from white European men. It was never intended to be a diagnostic tool for individual health but was later misapplied in medicine without adjusting for racial and ethnic diversity.

It Was Tested Using Data from Enslaved Black People:

In the 19th century, racist pseudoscience influenced how body measurements were used. Scientists like Louis Agassiz and Samuel Morton collected data from enslaved African people to argue that Black individuals had fundamentally different (and supposedly inferior) bodies compared to white Europeans. This racial bias informed later medical standards, including BMI, reinforcing false ideas about Black physiology.

BMI Ignores Racial Differences in Body Composition:

BMI assumes that all bodies store fat, muscle, and bone in the same way, but research shows that:

• Black individuals tend to have higher muscle mass and bone density, leading to overestimations of obesity and health risks.
• Asian populations often have higher health risks at lower BMIs, meaning they might be underdiagnosed for conditions like diabetes or heart disease.

If you check your BMI on the nhs site it asks for your ethnicity and adjusts accordingly.

I assume more recent research has updated the calculation

Well i agree that bmi is a flawed system.

But I'm not sure how you can be 'size 10 due to your height'? Surely you are just size 10 ? I can't see how you are obese if size 10.

We have discussed this before. The NHS site adjusts for ethnicity.
It's already told me I need to get my BMI below 23 ( pretty hard post menopause).
Dont see how it is racist.

You could also say it’s ageist and sexist.

I’m aware of the racist history of bmi in terms of why and how it was developed. Awful.

I think it still serves as a good indicator of healthy weight for most people today, as it is adjusted for different ethnic backgrounds.

Agree with that. Personally I think as an older woman if you have a bmi that's on the low side -albeit what the NHS says is the healthy range you're at risk of more infections, osteoporosis etc.
Don't know if anyone has researched this, but it is what I think.

I think this is a really good point for lots of things that rely on data. See also crash dummies (all men), facial recognition, lots of AI base data is used on predominantly caucasian data and even more predominantly on male data.

Thankfully the NHS now have taken this into account for the BMI but in a world ever moving towards reliance on data being used as the basis of AI which intern will be used to forecast and create policy it is really important that these issues are raised.

It’s just a blunt tool used as part of wider considerations to assess your health.

It’s draining people just looking to be offended all the time.

BMI is a starting point for a conversation with yourself and doctors about your weight and potential health risks. That all it is. It’s just a tool, one of many.

You can’t seriously think someone who is 5’3 and a size 10 weighs the same as someone who is 6’ and a size 10. The extra body mass is what causes the BMI to then say obese when you aren’t. it’s a shit system.

Obviously its different. But a size 10 person of 5 ft 3 wouldn't be overweight

It's far from a perfect system but the NHS calculator adjusts for ethnicity. I've certainly seen it documented in the info about Asian people being higher risk at a lower weight.

Also it doesn't make sense that you say your height made you "obese" that's taken into account. What's your height / weight?

If it's designed around men then it's of no use to us of any race.

Your post is conflicting. You say BMI was based on measurements from white European men* *
then say collected data from enslaved African people to argue that Black individuals had fundamentally different (and supposedly inferior) bodies compared to white Europeans
So, do you think Black people and White people have fundamentally different body compositions? Surely throughout the whole range of Black ethnicities, there are myriad body types, as there are in the re age of White ethnicities.
People’s bodies are a result of genetics. Think of it like breeding racehorses. The leanest, fastest horses would be selected to breed from, rather than a small, slow donkey of a horse. Because of their genetics.
Some White ethnicities have a propensity for being very tall, or having very blonde hair. Someone who’s of Nigerian ancestry may well look very different from someone who’s of Khoisan ancestry.
BMI is adjusted for ethnicity, age and sex. If you’re 4’ tall and weigh 10 stone you’re overweight. Its very easy!

Obese at a size 10? Are you under 4ft tall? I think if you’re an extreme outlier in terms of your height then the blunt tool of a BMI chart isn’t going to be helpful whatever your ethnicity.

This. And I thought the adjustment to take into account ethnicity meany that the "overweight"/"obese" categories started at a lower BMI for (some) non-white people? So I'm not sure how historical racism in devising the BMI formula affects whether OP is deemed obesefor her height at a size 10?

It's a blunt tool. It has a 3 stone range for my height. That's a lot of wiggle room to lie in the healthy range.
If you lie outside that range it's an indicator you need to look deeper at your health.

It's literally just a mathematical calculation - weight divided by height squared. It is a blunt tool and the nhs recognises racial differences but in general terms it is a fairly useful guide.

You don’t have to use BMI you can use other tools. You can use waist to height ratio or work out you body fat. The most easy way to work out if you are dangerously obese is to measure your waist

The BMI takes into account ethnicity so it will be lower thresholds for non white people for this reason as it recognises that some ethnicities are at a higher risk

If you have a high muscle mass don’t use BMI it won’t be the right thing for you

I really just wanted to hear some opinions - so thank you!

While 'racist' is a strong term, 'biased' may be more appropriate. Historically, research in this area has been deeply flawed, often lacking diversity. However, more recent studies have taken a more inclusive approach, examining body composition across various ethnic groups and the broader male and female diaspora.

South Asian/5ft1 - I remember being told I was in the obese category about 10 years ago when I was a size 10, at the docs surgery. I'm sure the NHS has made changes to the BMI calculator in that time.

I think bottom line - I find it to be less useful when calculating how "healthy" my weight is. More recently, I've been going by energy levels/how I'm sleeping/how I'm fitting in my clothes. I guess those are more indicative of what makes me feel good - less health-related.

Thanks Soontobe60 for replying! Your racehorse analogy oversimplifies things. Genetics matter, but epigenetics—how environment, history, and lifestyle affect gene expression—plays a huge role too.

The contradiction you pointed out isn’t really one. Early BMI was both flawed in its scope (based mostly on white European men) and later misused to push racist ideas about physical differences. The data from enslaved Africans wasn’t real science—it was an excuse to justify bias.

Yes, there’s huge variation within and across ethnic groups, but history, diet, and environment also shape bodies in ways BMI doesn’t fully account for. While it’s been adjusted for ethnicity, it’s still an imperfect tool that oversimplifies human diversity.

But that’s why you type your height into the calculator? It doesn’t say all women have to weigh the same amount..! The taller you are the more weight it allows. If you’re a true size 10 it won’t say you are obese.

Thank you LosingCount for replying. You are right - I think it's a fairly simplified tool but not for everyone!

Biased, or limited in its application or not representative might be better.