Obesity, defined as the presence of abnormal or excess body fat that impairs health, by definition, impairs health and is increasingly recognised as a chronic disease not unlike hypertension or diabetes.
But what exactly is the disease process?
Here an analogy with chronic kidney disease may be helpful.
For one, like chronic kidney disease, obesity can have a wide range of different underlying drivers. These can be genetic, environmental, iatrogenic (medications), or some other (unrelated) disease process.
Thus, in the same way that chronic kidney disease can result from polycystic kidney disease (genetic), lead toxicity (environmental), non-steroidal anti-inflammatory drugs (medications), or plasmocytoma (unrelated disease), obesity can result from Prader-Willi syndrome (genetic), highly processed foods (environmental), atypical anti-psychotics (medications), or craniopharyngioma (unrelated disease).
In kidney disease, each of these causes have different disease pathways, timelines, and prognosis, the end result, however, is an often progressive and irreversible loss of kidney function, which in extreme cases can end with the patient needing renal replacement therapy (like dialysis of kidney transplant).
Similarly, irrespective of the underlying cause, obesity, once established, generally becomes a life-long problem, which can often progress over time and may, in extreme cases, result in terminal incapacitating illness.
Secondly, irrespective of the underlying cause, chronic kidney disease, like obesity, can result in a wide range of associated disease processes.
Thus, irrespective of the underlying cause, progressive loss of kidney function results in a common pathway of related disease processes that can lead to fluid retention, hypertension, anemia, hyperparathyroidism, bone disease, and increased risk for infections and cardiovascular complications.
Similarly, irrespective of the underlying cause, progressive accumulation of abnormal or excessive body fat can result in a range of related disease processes ranging from metabolic problems (type 2 diabetes, gout, dyslipidemia, fertility issues), to mechanical issues (obstructive sleep apnea, GERD, plantar fasciitis, gonarthritis, urinary incontinence), to cancers (endometrial, breast, colon).
In addition, both chronic kidney disease and obesity can significantly affect overall physical and emotional well-being and quality of life.
As in chronic kidney disease, the exact processes by which obesity affects various aspects of health are distinct and involve specific pathophysiological pathways.
Thus, in the same way that we now understand how loss of kidney function can result in complications like anemia (loss of erythropoietin) or hyperparathyroidism (loss of activation of Vitamin D), we understand how accumulation of abnormal or excess body fat can lead to type 2 diabetes (reduced levels of adiponectin and increased intramyocellular lipid accumulation leading to insulin resistance) or obstructive sleep apnea (increased pharyngeal fat accumulation).
As in chronic kidney disease, not every patient with obesity develops every possible complication. Thus, for e.g. in the same way that not every patient with chronic kidney disease develops hypertension or bone disease, not every patient with obesity necessarily develops type 2 diabetes or sleep apnea.
In summary, as in patients with chronic kidney disease, where we now appreciate that irrespective of the different causal pathways leading to the loss of kidney function, there are discrete common pathways leading to typical complications, in patients presenting with obesity, irrespective of the wide range of pathways that can lead to the accumulation of abnormal or excessive body fat, there are discrete common pathways leading to the typical complications associated with obesity.
Incidentally, this view of obesity has important clinical consequences. Thus, as in patients with chronic kidney disease, obesity management had three distinct goals, each of which may require a different management strategy:
- Addressing the underlying drivers
- Halting or slowing progression
- Preventing or managing the complications
Busan, South Korea
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.
A few days ago I posted an article with the tongue-in-cheek rhetorical title, “Is there a role for dietitians in obesity management?”, to which, as readers should note, my clear answer (or so I thought) was “ABSOLUTELY!”.
Interestingly, the response to this post from the dietitian community was both humbling and indeed an honour. Not only did the post receive an unusually large number of lengthy and passionate comments (both here and on social media), but I also received a most thoughtful letter signed by well over 200 dietitians, suggesting I reconsider or at least clarify my post.
This overwhelming response to my post was humbling, because, I do not believe that there is anything I could possibly have written that would have elicited an even remotely similar prompt and passionate response from my own medical colleagues – clearly dietitians care strongly about what they do. Apparently, they also appear to pay attention to what I have to say – which is an honour indeed!
That said, I agree very much that some clarification is in order.
For one, as stated above, the title of the post was indeed entirely rhetorical – if I did, for even a second, have any doubts as to the important role that dietitians have in obesity management, I would probably not have bothered writing the post at all.
Secondly, I would have thought that both my opening and closing paragraphs would have made it entirely evident just how much respect I have for the professional expertise that dietitians have with regard to their discipline and their essential role in obesity management. I truly believe that it would be entirely fair to say that dietitians’ knowledge of biochemistry, disease processes, counseling techniques, client-centred care, and clinical passion are second to none (and I happily include my own colleagues in the comparator).
Furthermore, nowhere did I state or imply that my comments apply to ALL (or even the majority of) dietitians – in fact, I thought I had made it clear that the issues I raised applied to a small minority (perhaps no more than a handful?) of dietitians. (I did not single out anyone by name, as I do not believe in, nor intended, any ad hominem attacks).
In my post, I touched on a few different but related issues:
1) The unequivocal endorsement of obesity as a chronic disease.
2) Potential gaps in specific obesity training.
3) Reluctance (of at least some practitioners) to consider weight loss as a realistic (and often necessary) therapeutic option.
Apart from the fact (as I have done in countless previous posts) that I have called out members of my own (or for that matter, any) medical profession on the exact same issues, I am also fully aware that within any health profession there is a wide range of expertise, experience, and opinion on virtually any issue.
But, I do believe that each of the above-mentioned issues is of importance (not just for dietitians), and I will happily clarify my stance and thinking on each of them in subsequent posts.
As to why, if my comments apply to all health professions, I decided to single out dietitians for this particular post, the reasons are simple:
1) This specific post happened to be prompted by actual conversations over the past few months with several dietitians from across Canada, who all (independently!) raised similar concerns about what they thought was perhaps amiss amongst some (younger?) members within their profession when it comes to obesity management (again, no names!).
2) Ten years of blogging have taught me that to initiate a lively discussion with any post, it needs to be opinionated, one-sided, strongly worded, and provocative – anything less, is a waste of time (sadly, balance is boring!). If nothing else, my post certainly achieved that.
3) I truly do consider the role that dietitians have to play in obesity management of the utmost importance. Dietitians are in fact “THE” profession, that other health professionals most often look to when it comes to obesity management. With that comes immense responsibility, which I know dietitians take very seriously.
I promise that I will attempt to do my utmost to clarify and expand on the specific issues raised in my previous post in subsequent posts.
Hopefully these “clarifications” will be taken in the respectful and constructive spirit in which they are offered – I am fully aware that nothing in medicine is black and white; we all happily operate in shades of grey (as I always emphasize to my patients). I’m also very aware that today’s certainties may well turn out to be yesterday’s follies – as our understanding of disease processes and treatments evolve, so do our clinical approaches (as they should).
All I ask of you, is to bear with me…
“On November 13th the Camera dei Deputati of the Italian Parliament voted unanimously to approve a motion that recognises obesity as a chronic disease and asks the Government to implement specific actions to promote and improve obesity prevention and management.“ Luca Busetto, co-chair of the EASO Obesity Management Task Force.
Why is this important? Because only through the unequivocal recognition of obesity as a chronic disease can governments mobilise the immense resources need to prevent and manage it in people living with this chronic disease.
To be clear, not everyone living in a larger body has obesity – as I have written countless times before, health cannot be measured with scales or measuring tapes.
The disease “obesity” only exists when abnormal or excess adiposity affects health. Thus, the term “healthy” obesity is in fact a misnomer – there is no such thing. By definition the clinical term “obesity” should refer only to people who have a clear health impairment as a direct result of their adiposity.
That said, the Italian Governments all-party declaration of obesity as a chronic disease, will hopefully mean that Italians living with this chronic disease now have better access to preventive and therapeutic interventions.
I am thus happy to see that among the various commitments made towards a national plan, the Italian government also emphasizes full access to diagnostic procedures for comorbidities, to dietary interventions, as well as psychological, pharmacological and surgical approaches as indicated.
Hopefully other European countries, and in fact, countries the world over will follow this example and ensure that people living with obesity are no longer treated as second-class citizens when it comes to access to treatment for their chronic disease.
I spent the first 10 years of my professional life studying and treating hypertension. As a bit of a history buff, I dug out old books on hypertension and went back to reading papers on blood pressure that were written in the 20s and 30s. I also had numerous mentors, who were around well before the advent of modern diagnostics or pharmacotherapy. In retrospect, I believe that there is much we can learn from the history of hypertension.
In the early part of last century, as we learnt more about the physiology of blood pressure regulation, numerous forms of “secondary” hypertension were identified (e.g. renal artery stenosis, Conn’s Syndrome, pheochromocytoma, etc.). Although these were rare conditions, they taught us much about pathophysiology – but (to this day), most case of elevated blood pressure are still considered “essential”, meaning that they do not appear to have a defined cause (genetics and environment both play a big role but the details remain rather murky).
Although the link between elevated blood pressure, stroke, heart disease, and kidney failure were well-recognised, there were no good treatments. In fact, the history of medical and surgical treatment of hypertension during the first part of the 1900s was so dismal, that many were opposed to treating hypertension with anything other than a highly restricted low-salt diet. Prior to the 1950s, pharmacotherapy included drugs like sodium thiocyanate, barbiturates, bismuth, bromides, hexamethonium, hydralazine, or reserpine – drugs that were poorly tolerated and for which there was little evidence that they lowered mortality. In desperate cases, surgeons performed sympathectomies – a drastic and complex operation.
Given the dismal landscape of medication for hypertension, there were loud voices that challenged the whole concept of hypertension. After all, if there were no good treatments, would it not be best to leave the patients alone and perhaps just support them in other ways? There were prominent doctors who warned about the possible damage that lowering blood pressure could do (particularly to the elderly). Even those who supported treatment, suggested modest targets – 170/110 mmHh was deemed “not so bad”.
Then came the 50s. The first modern drug to be introduced was the oral-diuretic chlorothiazide. Then came, beta-blockers, ca-antagonists, ACE-inhibitors, ARBs, and renin blockers.
Now that effective medications were available, researchers could conduct long-term studies to prove that these medications were not only safe and effective in lowering blood pressure, but could actually drastically reduce the incidence of strokes, heart attacks, and kidney failure.
But even as these studies were ongoing, there were the “nay” sayers. People who pointed out that, given the dismal history of hypertension medications, these should have no place in the clinic. People, who, even if they conceded that the medications were more effective and safer that ever before, pointed out that there was not enough data to support their routine use. There were those, who warned against lowering blood pressure too far and those who decidedly did not consider elevated blood pressures in the elderly a worthwhile target. And of course, there continued to be those that felt that rather than trying to treat hypertension, we should focus all efforts on preventing it by declaring a war on salt.
How things have changed. Today, no doctor would think twice about prescribing anti-hypertensive medications to a patient with elevated blood pressure. No payer would refuse the coverage of anti-hypertensive medications. No medical student leaves medical school without training in hypertension management. In fact, the only excuse today for anyone walking around with elevated blood pressure is either that they have not been diagnosed or are not taking their medications as prescribed (of course there are still some patients for whom the existing treatments are not tolerated or do not work, but these are few and far between).
I still recall the debates at conferences (my first hypertension conference was the World Hypertension Conference in Kyoto in 1988) on whether or not hypertension is a disease or just a risk factor. I recall proponents suggesting that simply improving lifestyles (without lowering blood pressures) would be as useful if not better for patients than exposing them to life-long pharmacotherapy (after all essential hypertension is just a “lifestyle” disease). I remember arguments about definitions and targets, about diagnostic strategies and therapeutic pathways (e.g. is it better to increase the dose, switch, or add-on?).
Funnily enough, I am reliving much of this history with obesity. There are those who, given the dismal past of anti-obesity medications, are vehemently opposed to the very notion that anti-obesity medications will one-day have a place in clinical obesity management. There are those, who given the past failures with dietary approaches (not unlike the failure of low-salt diets to produce long-term blood pressure lowering in most people), are ready to abandon dietary approaches all together (at least in the context of weight loss). Indeed, there are those who continue to argue that obesity is not really a disease but simply a risk factor attributable largely to lifestyle “choices”.
It took about 100 years for us to get to hypertension management as it exists today. In obesity, I think the wheels are moving a lot faster, although to many living with this disease, movement may appear glacial. Remember, less than 30 years have passed since the discovery of leptin. Only now are we entering the “modern” era of anti-obesity medications.
Yes, the debates about definitions and targets and treatment plans will continue but I am confident that sooner or later, we will get to the point where helping patients manage their obesity will be as routine, free of bias or judgement, and accepted as helping patients manage their hypertension.
Over the past 30 years, I have actively been involved in nutrition research – conducting numerous carefully controlled dietary studies ranging from the impact of electrolytes on blood pressure and renal function, to the impact of micro and macronutrients on insulin resistance and metabolism, to the role of genetic factors in response to nutrient intake. In all of this, dietitians have always been key players in my research team helping with the design and execution of these studies.
In my clinical work, I have regularly depended on the tremendous expertise of dietitians in the care of my patients with hypertension, chronic kidney disease, dyslipidemia, and type 2 diabetes – in virtually all of these conditions, dietitians have helped my patients on a wide range of treatments ranging from medications to chronic hemodialysis improve their diets, thereby significantly improving control of their underlying diseases or averting complications.
I have practiced medicine long enough to remember the days of prescribing low-salt diets before the modern era of anti-hypertensive medications, dietary lipid management before the introduction of statins, and worrying about glycosuria well-before most people considered type 2 diabetes to be an actual “disease” and not just a “risk factor” of questionable significance that happens to old people.
Thus, it is with a bit of wonder that I sense an increasing reluctance of some dietitians (at least in Canada) to fully embrace the important role that they could play in obesity management. At times, in recent conversations, I was surprised (and concerned) that more than a few (younger?) dietitians are not only uncomfortable with addressing obesity in their clients, they are in fact ambivilant (if not frankly hostile) to the very idea that obesity is a disease or that dietary interventions to support weight loss have a role to play in obesity management.
This, of course does not apply to the many excellent and skilled dietitians working in the many bariatric centres and obesity clinics, without who many of the successful outcomes in medical and surgical treatment of this chronic disease would hardly be possible.
Rather, ambivalence towards nutritional obesity management appears to emanate from folks who clearly do not (yet) have a sound understanding of the complex psycho-neurobiology of obesity or the mode of action and effectiveness of evidence-based obesity treatments that include medications and surgery.
Indeed, I cannot but wonder about these dietitians’ qualifications to actually contribute to the care of patients struggling with obesity. Imagine having your patient with diabetes being counselled by a dietitian who has never heard of insulin or glucagon, has only a vague idea of how SGLT2 agonists, DPP IV inhibitors, or GLP-1 analogues work, and firmly believes that typ2 diabetes can be fully controlled or even “cured” if patients only followed “healthy eating” tips. Imagine having your cholesterol managed by dietitians who don’t “believe” in cholesterol or statins, or your hypertension managed by dietitians who believe that some variation in blood pressure levels is acceptable and that simply reducing your salt intake and perhaps following the DASH diet is all you need to get off those terrible anti-hypertension meds.
This is unfortunate. Not only is there room for dietary interventions in obesity management, but, as in other chronic diseases, dietitians can (and should) be a key partner in the therapeutic management of people living with this chronic disease.
However, to be effective, dietitians need to first of all be comfortable with the very notion that obesity is a chronic disease. In the same way that any dietitian who does not “believe” in hypertention or type 2 diabetes should probably best stay away from counseling clients with these conditions, I would be wary of any dietary advice regarding managing my obesity from a dietition who does not “believe” in this disease.
Next, I would also expect any dietitian attempting to counsel patients for their obesity to have a robust understanding of the complex psycho-neuro biology of obesity, be aware of their own biases and misconceptions about people living with obesity, and be fully informed and aware of current evidence-based obesity treatments, including medications and surgery.
I would expect no less of a dietitian working with my patients living with hypertension or chronic kidney failure. Simply trying to get people living with obesity to follow a healthy balanced diet is not enough – different people living with obesity require different dietary approaches – approaches that change from patient to patient dependent on patient preferences, responses, circumstances, expectations, severity of disease, as well as concomitant use of medications and surgery.
I know that dietitians can do this when managing patients with a host of other chronic diseases – why some of them struggle to similarly serve clients with obesity, is frankly beyond me.
As we will soon see in the new Clinical Practice Guideline for Obesity Treatment in Adults to be released in 2020, there is strong and robust evidence to support nutritional interventions and dietary management of people living with obesity (in adjunct to, not instead of, medical and surgical management). But is it up to the dietetic profession to fully embrace this role and prepare its members for it by ensuring that their members fully understand and appreciate the emerging science of this complex chronic disease.