Arguments For Calling Obesity A Disease #2: It Is Driven By Biology

Continuing in my miniseries on reasons why obesity should be considered a disease, I turn to the idea that obesity is largely driven by biology (in which I include psychology, which is also ultimately biology). This is something people dealing with mental illness discovered a long time ago – depression is “molecules in your brain” – well, so is obesity! Let me explain. Humans throughout evolutionary history, like all living creatures, were faced with a dilemma, namely to deal with wide variations in food availability over time (feast vs. famine). Biologically, this means that they were driven in times of plenty to take up and store as many calories as they could in preparation for bad times – this is how our ancestors survived to this day. While finding and eating food during times of plenty does not require much work or motivation, finding food during times of famine requires us to go to almost any length and risks to find food. This risk-taking behaviour is biologically ensured by tightly linking food intake to the hedonic reward system, which provides the strong intrinsic motivator to put in the work required to find foods and consume them beyond our immediate needs. Indeed, it is this link between food and pleasure that explains why we would go to such lengths to further enhance the reward from food by converting raw ingredients into often complex dishes involving hours of toiling in the kitchen. Human culinary creativity knows no limits – all in the service of enhancing pleasure. Thus, our bodies are perfectly geared towards these activities. When we don’t eat, a complex and powerful neurohormonal response takes over (aka hunger), till the urge becomes overwhelming and forces us to still our appetites by seeking, preparing and consuming foods – the hungrier we get, the more we seek and prepare foods to deliver even greater hedonic reward (fat, sugar, salt, spices). The tight biological link between eating and the reward system also explains why we so often eat in response to emotions – anxiety, depression, boredom, happiness, fear, loneliness, stress, can all make us eat. But eating is also engrained into our social behaviour (again largely driven by biology) – as we bond to our mothers through food, we bond to others through eating. Thus, eating has been part of virtually every celebration and social gathering for as long as anyone can remember. Food is celebration, bonding, culture, and identity – all… Read More »

Full Post

Arguments Against Obesity As A Disease #9: Its Just A Risk Factor

Next, in my miniseries on arguments I commonly hear against the notion of calling obesity a disease, is that it is “just a risk factor” for other diseases. This may be true, if you just (wrongly) considered elevated BMI as your definition of obesity, because no doubt, people with higher BMI levels carry a higher risk for obesity related complications including type 2 diabetes, sleep apnea, fatty liver disease, hypertension – just to name a few. (Note that increased risk is not the same as actually having the condition!). However, when you use the actual WHO definition of obesity, namely, “accumulation of excess or abnormal fat that impairs health”, obesity is no longer just a risk factor – it is now (by definition) impairing your health, which makes it far more than just a risk factor. So while someone with a BMI of 35 may be at risk of developing obesity (not the same as having it), when their excess fat actually starts impairing their health, it de facto becomes a disease in its own right. Even then, one might argue that obesity itself is not the disease, rather the complications of obesity are the real disease. This notion is both right and wrong. There are many conditions that are both diseases in their own right as well as risk factors for other diseases or complications. Take type 2 diabetes for instance – it is both a disease in itself but also a risk factor for coronary heart disease or end-stage kidney disease. Take hypertension – a disease in its own right but also a risk factor for strokes and heart attacks. Take gastro-oesophageal reflux disease, which is also a risk factor for Barrett’s disease and oesophageal cancer. Take fatty liver disease, which is also a risk factor for cirrhosis. Gall bladder stones, which is also a risk factor for pancreatitis. Multiple sclerosis, which is also a risk factor for neurogenic bladder and pyelonephritis. The list goes on and on. So just because obesity is also a risk factor for a wide range of other medical problems, it does not make obesity any less of a disease in its own right. When excess or abnormal body fat affects health – it’s a disease. When it doesn’t, it’s at best a risk factor. That, is perhaps a subtle but important distinction. @DrSharma Toronto, ON

Full Post

Arguments Against Obesity As A Disease #2: Inconsistent Relationship Between Body Fat And Health

Yesterday, in my brief series on the pros and cons of calling obesity a chronic disease, I addressed the issue of BMI as a poor definition of obesity (understood here as “abnormal or excess body fat that affects health”). Another common argument I hear from those who do not support the notion of obesity as a chronic disease, is that there is an inconsistent relationship between body fat and health. This is no doubt the case. Indeed, whether or not your body fat affects your health depends on a range of factors – from your genetic predisposition to certain “complications” to the “nature” of your body fat, factors that cannot be captured or assessed by simply stepping on a scale. Often, this variability in the relationship between excess body fat and its impact on health, is used to argue against a “causal relationship” between the two. This argument is often presented along the lines of, “If obesity is a disease, how come I don’t have diabetes?”. Where the direct impact of excess body fat on health should be evident,  is when the amount of excess fat poses a direct “mechanical” problem that impedes physical functioning. This impact, however, is likely to vary from one person to the next. A good example of this, is obstructive sleep apnea, where an increase in pharyngeal fat deposition is directly and causally related to the airway obstruction. The causal relationship of pharyngeal fat and the symptoms is directly evident by improvement in symptoms following surgical removal of the excess fat (an operation that is seldom undertaken due to possible complications and redeposition of fat). There is also substantial evidence that significant weight loss (such as induced by bariatric surgery) results in a dramatic improvement in apnea/hypopnea index and sometimes even in complete resolution of the problem. Yet, not everyone with excess weight develops obstructive sleep apnea. One of the factors that explains this variation, is the anatomical dimension of the pharyngeal space, which varies significantly from one person to the next. So, just how much excess fat in the neck region results in symptoms (if any) will necessarily be highly variable. This is not an argument against the relationship between excess body fat and obstructive sleep apnea, it is just the expected variation between individuals that is evident in many diseases. Likewise, when the amount of excess fat impairs the body’s capacity to perform essential functions (from mobility… Read More »

Full Post

Arguments Against Obesity As A Disease #1: BMI Is Not A Good Measure Of Health

Over the past months, I have been involved in countless discussions and debates about whether or not obesity should be considered a chronic disease (as it has by the American and Canadian Medical Associations and a number of other organisations). I therefore thought it perhaps helpful if I discussed each of the common pros and cons on this issue in a series of blog posts. To begin this short series, I’d like to discuss perhaps the most common argument against calling obesity a disease, namely, the well-known shortcomings of BMI. As regular readers will know, I have long railed against the use of BMI as a clinical definition of obesity as it is neither a direct measure of body fatness nor does it directly measure health. In fact, its specificity and sensitivity to pick up health problems commonly associated with obesity (such as type 2 diabetes or hypertension) is so limited, that it would not even remotely meet the criteria commonly applied to other diseases for diagnostic testing. Thus, especially around the BMI cut off of 30 (widely used to “define” obesity in Caucasians), anywhere from 5-25% of individuals would be considered pretty healthy by almost any clinical measure. Even at higher BMI cut offs, it is not all that difficult to find individuals with very mild to non-existent health problems related to their size (as in EOSS 0-1). While some of these individuals may well go on to develop health problems over time, “risk for” a disease is generally not considered a “diagnosis” of that disease. Thus, even if an elevated BMI may indicate increased risk of obesity, it cannot be used to “define” an individual as having the “disease of obesity”. This shortcoming of BMI has been widely (albeit perhaps not widely enough) recognised, which is exactly why, for e.g. the Canadian Medical Association, in their declaration of obesity specifically states that, “BMI is a useful operational definition for obesity but should not be used as the defining characteristic of the disease….in the case of individuals who are very obese, issues of definition and measurement are not relevant.” (emphasis mine) Similarly the WHO in its definition of obesity states that, “BMI provides the most useful population-level measure of overweight and obesity as it is the same for both sexes and for all ages of adults. However, it should be considered a rough guide because it may not correspond to the same degree of fatness… Read More »

Full Post

Guest Post: ICD-10 Code Coming For Sarcopenic Obesity

Today’s guest post comes for Carla Prado, PhD, Assistant Professor and CAIP Chair in Nutrition, Food and Health, University of Alberta, Edmonton, Canada Although obesity is often conceived as excess fat mass, we now know that individuals with obesity may have normal, high or low muscle mass. Low muscle mass (sarcopenia) is a debilitating condition associated with poor physical function, morbidity and mortality. The simultaneous appearance of obesity and sarcopenia (sarcopenic obesity) is an emerging area of interest as its prevalence is at rise. Importantly, sarcopenic obesity is the worst‐case scenario as both excess fat and low muscle mass have its own (and perhaps synergistic) metabolic and health‐related consequences. As a “hidden condition”, sarcopenia in individuals with obesity is undetectable by use of body weight or body mass index. The need for sophisticated measurements of body composition has limited our ability to fully understand this condition, as well as to establish preventive and treatment strategies, limiting the translation between research and clinical practice. This is about to change. As of October 1st, 2016, sarcopenia will have its own diagnostic code (ICD‐10 code). The World Health Organization International Statistical Classification of Diseases and Related Health Problems (ICD) is a standard tool used to report diagnosis and in‐patient procedures. Hopefully, this will mean that the official record and identification of sarcopenia in medical records will improve our understanding of the epidemiology, health management and treatment of this condition. According to the Aging In Motion Coalition, the establishment of an ICD‐10 Code represents a major recognition of the importance of sarcopenia, removing barriers to treatment and research on several fronts. Such barriers include awareness and attention, clear indications for treatment, and reimbursement. We expect Canada will champion the study of sarcopenia and sarcopenic obesity with special calls for funding, advocacy and public awareness. Carla Prado Edmonton, AB

Full Post