Obesity Is Not A Four-Letter Word

To most of us, the word “obesity” is associated with a wide range of strongly negative connotations. The persistent and widespread weight-bias and fat-phobia promoted by stereotypical (but misleading) images, associations, and assumptions, together with widespread misinformation and misrepresentation, makes a dispassionate and objective use of this term difficult – to the degree that we may wish to avoid it altogether.

Indeed, the term “obesity” means different things to different people – the spectrum is extraordinarily vast, ranging from it being hurled as a personal insult to its use as a medical diagnosis. It is the latter use that I will concern myself with in this post (not to imply that analysing and acknowledging other uses of the term may well be as important).

In a medical context, the term has generally been applied to all individuals, whose body mass index (BMI) appears above a certain cut-off. This practice has long been criticised (not least by me) on the basis that weight or size is simply not an objective measure of health and that BMI does a rather poor job of characterizing individual health risks.  Indeed, it is now well established that good health is possible over a wide range of body shapes and sizes and therefore attempting to base a disease definition on numbers on a scale or measuring tape without additional measures of health, fitness, or well-being are fundamentally flawed.

Thus, with the push for recognition of obesity as a chronic disease (more on this in future posts), there has also been a push for modifying the definition of what constitutes obesity in a medical sense. The emerging consensus shared by various medical bodies and experts in the field, is that the diagnosis of obesity needs to be based on actual measures of health rather than simple anthropometric measures.

A current working definition of what constitutes obesity in a medical sense, is the presence of excess or abnormal body fat that impairs health, the operative word here being “impairs”. Without an impairment in health, there is no disease, ergo, no obesity. This definition immediately excludes all individuals, who, irrespective of shape or size, are in perfect health.

Another important aspect of this definition is that there should exist a direct link between the presence of abnormal or excessive body fat and the health impairment. This is a lot less straightforward than it appears, as most health problems can have more than one cause and not every health problem in a person with abnormal or excess body fat is necessarily related to their adiposity. Here one may have to look for evidence that weight gain makes the problem worse and weight loss makes the problem better before concluding that someone has obesity.

Thus, the medical diagnosis of obesity requires substantially more than just a scale or a measuring tape. It actually requires a medical encounter that includes clinical assessment and the use of clinical judgement and may well require additional diagnostic laboratory and imaging studies or even treatment attempts. Purists may find this cumbersome and somewhat fuzzy, but they should perhaps be reminded that there are countless medical diagnoses that require similar levels of assessment and clinical judgement – in fact, only a rather small group of medical diagnosis are based on a single discrete and objective measure.

To make matters even more complicated, obesity, like many other medical conditions, is extraordinarily heterogeneous as to its causes, its manifestations, its response to treatment, and prognosis. I have previously likened this to cancers, which all share the condition of “malignancy” but are vastly different in terms of clinical presentations and prognoses. Thus, others and I have sometimes used the term “obesities” rather than just “obesity”.

I can readily see why this degree of complexity in defining what obesity actually is (at least in the medical sense), can be extremely dissatisfying to practitioners, patients, policy makers, and the general public, all of who would likely prefer simpler solutions. Unfortunately, things in medicine are rarely neat and tidy or set in stone – a certain fluidity and plasticity in definitions and disease paradigms is the rule rather than the exception.

So, while in medicine, I can see an emerging consensus that characterisation of obesity as a disease needs to be based on actual measures of health rather than just numbers on a scale, I also understand why the use of this term outside of medicine remains highly problematic. Here, I can readily see why, given its strong negative connotations, many would want to abandon the use of this term altogether and frankly, I do not disagree.

Even within the context of medicine, we must be cautious in how we use and to whom we apply the term. For one, we must consistently adhere to the principles of people-first language – there are no “obese” people, only people who have “obesity”! We must also acknowledge and recognise that this term has strong negative connotations for most people, and that we need to take the time to ensure that clients understand exactly what we mean by this term when we use it in our charts, medical records, and inter-professional communication.

Edmonton, AB