Don’t Say O!

Why it's time to retire harmful weight-centric labels in healthcare, policy, and everyday language.

There are some words that it is time, as a global society, to retire. We're talking about the “O words”, ob*se and ov*rweight to be exact. 

The “O Words” are so widely used and accepted in society and are deeply embedded in contemporary health discourse. We see and hear them, in healthcare systems, research papers, media headlines, government policy, and in everyday conversations where they are often delivered under the guise of concern. 

The words are often presented as neutral descriptors, but they are not neutral.

These words carry history, hierarchy, and have been used for decades to categorise, judge, and justify unequal treatment. The harm attached to them does not disappear simply because they are widely used or clinically familiar. 

We are not the first to question these terms. Researchers, advocates and people with lived experience have been challenging use of the O Words for decades. We are simply adding our voice to a long-standing and evidence-based call for change. 

Language evolves. When words cause harm, distort the way we understand health and bodies, and justify rampant discrimination they should evolve out of use, especially when the people most impacted by their use are the ones who are begging you to stop. 

The O Words Medicalise Human Diversity 

The O Words are rooted in Body Mass Index (BMI) thresholds. BMI was developed as a population-level statistical tool and was never designed to diagnose individual health. Yet over time, the O Words have become the backbone of clinical categorisation and public health policy. 

Human bodies vary across genetics, culture, geography, age, and socioeconomic context, something the BMI never accounted for. That variation is normal, so when it is reduced to a limited set of weight categories, normal human variation is reframed as pathology, and come bodies become inherently problematic. 

That reframing shapes systems, funding priorities, and clinical decision-making, all of which carries huge consequences. 

The Word “Over” Is Doing a Lot of Work 

In particular, the word “ov*rweight”; it might sound straightforward, but over what weight?  

A healthy weight? According to which measure? Based on whose body? Under what cultural standards? In which decade?  

Human bodies are shaped by genetics, epigenetics, environment, access to resources, stress, culture, and countless other factors. There is no single baseline from which deviation automatically signals a problem. Yet the word assumes that such a baseline exists AND that moving beyond it is inherently wrong. 

Did you know that in 1998, the BMI thresholds were changed overnight? Millions of people went to bed a “normal weight” only to wake up as “ov*rweight”, without their body changing one iota.    

When a definition can be altered by committee and instantly redefine millions of people, it is difficult to argue that it represents fixed biological truth. 

Once we recognise how unstable and context-dependent these thresholds are, the words themselves begins to unravel. 

O Words Are Inaccurate Proxies for Health 

Body size is a poor standalone indicator of health. People across the weight spectrum experience both chronic illness and metabolic stability. Health outcomes are shaped by complex and interacting factors, including social determinants, access to care, stress exposure, income, sleep, nutrition and movement. These are established findings within public health research.  

And yet the O words continue to be used as shorthand for health risk, as though body size alone offers reliable clinical insight. 

Despite decades of evidence, weight remains a primary screening tool, a policy lever, and a clinical justification for large-scale intervention. It is invoked to describe crises, calculate economic burden, and predict disease, even though behavioural, environmental, and socioeconomic factors are consistently shown to have greater influence on long-term health outcomes than body size. 

In a weight-centric system, body size becomes the focus of intervention. Attention is directed toward weight reduction rather than toward improving access to care, reducing stress exposure, increasing food security, or addressing discrimination. 

This misalignment has material consequences. Clinical attention narrows, symptoms are attributed to weight rather than investigated, appropriate treatment are delayed, and preventable conditions go undiagnosed. Individualsare reduced to a category rather than treated as whole people with complex medical needs. And when people are repeatedly reduced to a stigmatised category, the stigma itself becomes a health risk. 

The issue is not merely that the O words are imprecise or make people uncomfortable. It’s that their continued use reinforces a weight-centric model that is inconsistent with contemporary evidence about what is health-promoting and what actually drives positive health outcomes. 

The O Words Reinforce Stigma 

The O words do not sit in a vacuum, they exist within a culture that routinely frames larger bodies as failures, burdens or crises. 

It is not just that the O words are deeply flawed and inaccurate, it is that continuing to use them as proxies for health sustains a model of care that overlooks complexity and perpetuates harm. 

The words are also highly stigmatised, and research consistently demonstrates that weight stigma is associated with poorer physical and mental health outcomes. Think increased stress, healthcare avoidance, disordered eating behaviours, poorer health outcomes, and long-term risk of chronic conditions.  

The biases of individual doctors and health professionals also negatively impact clinical decision-making, with studies showing that discrimination by doctors has the same mortality risk as smoking (we wish we were making this up, but it's true, and it's our Roman Empire).  

When labels carry strong social stigma, its routine use cannot be separated from that context. 

Language reflects culture, but it also reinforces it. If we are serious about improving health outcomes and building ethical healthcare systems, we must be willing to examine the terminology that sustains harmful narratives and then retire them where necessary. 

“But It’s a Medical Term.” 

Many terms once considered medically acceptable have been revised or retired in light of new evidence and evolving ethical standards. 

As evidence evolves and our understanding of medicine evolves, our language must evolve with it. When language encodes judgment while presenting itself as objective, it moves beyond description and begins shaping expectation and intervention. When we know better, we should do better.  

Because the question is not whether the terms exist in a classification system, the question is whether its continued use contributes to better health outcomes and respects human dignity. If the answer is no, and in this case, it is a gigantic neon flashing NO, then reassessment is not radical, it is responsible.

Why This Conversation Matters on 4 March 

We are publishing this blog on 4 March - International Fat Liberation Day. 

The date coincides with World Ob*sity Day, a global campaign that frames higher-weight bodies as a public health crisis and burdens to be eliminated. Each year, headlines focus on prevalence rates, projected healthcare expenditure, and the language of emergency, reinforcing the perception of body size as a collective threat.  

International Fat Liberation Day was created in protest of that framing; to challenge the assumption that body size alone constitutes a public health emergency and to question the political and economic forces that shape such narratives. 

The O words sit at the centre of this discourse. They are not incidental descriptors; they are the linguistic scaffolding that allows complex social and health issues to be collapsed into a single, visible characteristic: body size. 

Publishing this blog calling for the elimination of the O Words on 4 March is therefore not symbolic. It is an acknowledgment that the language we normalise in global health conversations has material consequences. If we want more accurate, ethical and effective approaches to health, we must be willing to interrogate the terminology that underpins current models. 

What To Say Instead 

Retiring harmful language does not mean abandoning clarity. It means choosing words that are respectful and aligned with contemporary evidence. 

We encourage the following principles across healthcare, policy, media and community settings:

1. Use “people in larger bodies” in policy and systems conversations. 

This centres humanity rather than pathology.   

2. Use “higher-weight” where comparison is clinically necessary. 

It is descriptive without implying defect or deviation. 

3. Avoid referencing body size at all when it is not relevant. 

 In many contexts, body size is not a relevant or useful piece of information.  

4. Focus on health conditions, not body size. 

Say: 

• People with hypertension 

• People with type 2 diabetes 

• People experiencing joint pain 

These conditions affect people across body sizes and size alone does not define risk. When we focus on conditions rather than size, we improve clarity and reduce bias. 

5. Use “fat” as a neutral descriptor - but use it with caution. 

The word fat has been reclaimed by the fat community who intentionally use the word this way. Neutralising it reduces its power as a weapon and removes the moral charge often attached to size. That said, when used outside of the community, existing biases may distort the words neutrality, so please consider context or include a discliamer that the word is a neutral descriptor. 

In the coming weeks, we will be releasing a comprehensive Language Guide for Body Size, with practical recommendations for clinicians, researchers, media professionals, workplaces, educators, and everyone. Stay tuned, we are busting at the seams to release this!  

The Words We Choose Create Ripples 

The language we use matters. 

It shapes how people are treated in clinics and classrooms, it shapes policy priorities and research agendas, it shapes media narratives and how individuals speak about themselves and to each other. 

When we change our language and set boundaries around the terms we will and will not accept, those choices ripple outward. 

Retiring harmful terminology is not about political correctness. It is about accuracy, dignity and improving health outcomes for everybody. 

The O Words have shaped public discourse for decades and are in direct conflict with the outcomes we claim to value. Let's leave them in the past.