The BMI calculator doesn’t work for everyone (Picture: Ella Byworth for Metro.co.uk)

I recently changed my life insurance provider and my initial quote was fantastic.

However, once it was processed through their system, I discovered it had increased.

Yes, light skin gets you further in the entertainment business, and probably in life – but change has begun

The reason why? My Body Mass Index (BMI) was too high.

Now in all fairness my BMI is higher than it should be but it did get me thinking about a long held theory of mine that the BMI calculator doesn’t work well for black women.


This theory is based on the stringent scientific observation of my friends and family.

Case in point, my sister is naturally very muscular and has impressive hips and a butt. Looking at her you’d never think she was obese, which is what her BMI calculates her to be.



This is a potential issue because BMI is used by the medical profession to quickly determine a person’s weight in relation to their height.

It is often used to measure the risk of developing type 2 diabetes, as well as other metabolic diseases such as hypertension, high cholesterol and heart disease.

Because of this, it has become the de facto measure of how healthy a person is.

In addition to insurance companies, certain professions also use it to determine a candidate’s eligibility.

It’s even used to determine if you are eligible for some medical procedures such as IVF and surgery.

So I began to wonder, are black women being unfairly penalised by an outdated measure that potentially discriminates along the lines of race?

It would seem the answer may just be yes.

BMI has its limitations because it does not take into account differing body shapes that are not a result of excess body fat.

The BMI also does not distinguish between body fat and muscle mass, which is why muscular athletes can have a high BMI, particularly as muscle is heavier than fat.

New research suggests that higher muscle mass is not just an issue for athletes.

A 2011 study published in the research journal Obesity found that while white women with a BMI of 30 or more and a waist circumference of 36 inches or more were at greater risk for diabetes, high blood pressure and high cholesterol, black women with those same numbers were considered medically healthy.

It further theorises that the weight gap between white and black women may have to do with how body fat is distributed differently throughout the body.

There are a number of reasons the BMI calculator doesn’t work (Picture: Ella Byworth for Metro.co.uk)

These findings echo a 2009 study which revealed that black people had less body fat than white people, even when they had the same BMI and waist measurements, which led to a theory that muscle mass may be higher in black people.

Even if you take the issue of race out of the equation, BMI is still a woefully inadequate and inaccurate measure of obesity and, as a result, health.

The National Institute For Health and Care Excellence is currently reviewing its use.



So if BMI is so problematic, why is it still so widely used?

‘It’s very hard to change something that’s so set in stone,’ says Dr Margaret Ashwell, President of the Association for Nutrition.

‘It needs to be put into policy and if I had devoted my whole life to political lobbying on this issue, perhaps something might have changed.

‘I haven’t done that but I have been saying the same thing for twenty odd years and the more I say it, the more evidence there is to support it,’ she adds.

In regard to body fat, there are other measurements recommended for assessing the risk of obesity-related diseases.

Guidelines from the National Heart, Lung and Blood Institute recommended looking at waist circumference.

But even this isn’t entirely accurate when used in isolation. Dr Ashwell promotes the use of waist-to-height ratio as the most accurate measure of obesity.

This recommendation is backed by a 2017 study by Leeds Beckett University.

Waist-to-height ratio works well regardless of race. It’s also accurate for children as well as adults of any gender.

Health risks start when your waist measurement is more than half your height.

It’s an early warning sign that you are storing your fat around your middle, which can lead to a variety of health problems in the future, something the BMI often discounts.

There are some places around the world further ahead in getting it into policy such as New Zealand, who use it in their survey data.


Thailand also has a government policy which measures people’s waist to height ratio and even uses a piece of string to do it.

You measure a person’s height using a piece of string then cut or fold it in half and put it around their waist and it should fit.

‘They’ve managed to get the process down to something that doesn’t need a tape measure, scales or equipment so it can be done anywhere around the world’ says Dr Ashwell.

‘If you want a scientific message to be accepted as public health policy it needs to be simple. Which is why BMI works so well.

‘BMI does have its uses – because it’s used everywhere it has helped us build continuity in our data.

‘But for the man in the street to get an early health warning signal, waist-to-height and a piece of string is more effective.’

MORE: It’s time we talked about the ethnicity pay gap

MORE: People of colour need to pick their battles and Kim Kardashian’s ‘Bo Derek’ hairstyle isn’t one

MORE: As a carrier of the sickle cell gene trait, I have to be extra selective about who the father of my kids will be

Advertisement Advertisement