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Arguments Against Obesity As A Disease #7: Medicalizes A Behaviour

ABOM logoContinuing in my miniseries on objections I have heard against calling obesity a disease, I now address the argument that, doing so “medicalizes a behaviour”.

This argument is of course based on the underlying assumption that the root cause of obesity is a behaviour.

This is perhaps true at the most superficial level of understanding of obesity – yes, there are behaviours that can promote weight gain like eating too much, sedentariness and working shifts.

Note however, that nowhere in the WHO definition of obesity as a “disease that results from excess or abnormal body fat that impairs health”, is there any mention of behaviour whatsoever.

This is because for many people, the relationship between behaviour and weight gain is not at all as straightforward as many think.

Take for example physical activity – although over 95% of Canadians do not meet even the minimum criteria for daily physical activity (a behaviour), only 20% of Canadians have obesity (using the BMI 30 cutoff for the sake of argument).

So if behaviour (not moving enough) is touted as one of the root causes of obesity, why does not 95% of the population have obesity?

The simple answer is that for any given level of physical activity (or rather lack of it), some people gain weight while others don’t.

Similarly, if you believe that eating a lot of junk food (a behaviour) is the root cause of obesity, you will have to explain why not everyone who eats a lot of junk food has obesity and why a lot of people have obesity despite never touching the stuff.

No matter what behaviour you pick, it will never explain all (or even most) of obesity and there will always be plenty of people with those exact same behaviours, who manage to maintain a “normal” weight with no additional effort.

As I have previously outlined in blog posts and articles. “behaviours” leading to obesity, if anything, are no more than a symptom of underlying root causes of energy imbalance that can be related to a wide range of psychological, social and/or biological factors, with the precise cause varying widely from one person to the next.

Thus, equating “behaviour” with “obesity” only happens in the minds of people who fail to see obesity for what it actually is – a complex heterogenous often multifactorial disease characterized by excess or abnormal fat tissue that impairs health.

Thus, all that declaring obesity to be a disease is really doing is “medicalising” obesity (which is of course exactly what medicine needs to do) – it is not “medicalising” a behaviour because obesity is not a “behaviour”.

That is not to say that some pathological behaviours (e.g. binge eating disorder) may lead to weight gain. But most of obesity is attributable to “normal” behaviours in an “abnormal” environment.

And so once again, I would like to remind readers that obesity is not a behaviour (unlike smoking or smoking cessation – which is!) – see here for an explanation of the difference.

Toronto, ON


  1. “(M)ost of obesity is attributable to “normal” behaviours in an “abnormal” environment.” Preach it, Dr. S! This is the central lesson that most people in white coats still need to embrace. And the abnormal environment is not merely toxic food culture (that the obese person is supposed to resist or moderate), but also the biological environment (body) of the person who has obesity, which may be broken by serial dieting, endocrine disruptors, or the hundreds of other factors that contribute to weight gain that you have dealt with in other posts.

    As for the specifics of this post. I have heard the argument that calling obesity a disease “medicalizes a characteristic.” It’s not a behavior-based argument so much as an aesthetic argument.

    As for my reaction to the general thesis of this series, I get what you’re saying but I still choke at the word “disease.” It’s probably my own issue. I have stigmatized the word “disease.”

    All that said, I prefer to tell people I manage the “condition” of obesity. I try to explain to my doctors that I am unusual in how successful I am in that management, but one of my doctors has begun insisting that “I need to watch it” because my BMI has crept to a 26.53. Given that my highest established weight put my BMI at 32.5 (in 2001), and given that I can no longer run since I lack adequate cartilage in my left foot (running was an integral part of my first 7 years of weight-loss maintenance), I personally think she needs to “watch” her own mouth. But I haven’t said that out loud. Some day I would love to see a post on how we patients can help educate our physicians. (Hint: bringing them copies of your blog posts doesn’t seem get through. I’ve tried that.)

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  2. Your differentiation of smoking as a behaviour and obesity as not a behaviour misses the point. Obviously the relevant behaviours in the case of obesity are eating and activity, which are of concern because of their presumed link to the pathological physical state (disease) called obesity. Smoking is a behaviour, and it too is only of concern because of its link to pathological physical outcomes. Furthermore, just like in the case of eating and exercise, smoking behaviour has multiple causes.

    The dismissal of eating and activity as causes of obesity because some (or even most) people who eat junk food or do not exercise do not become obese is a problematic conclusion. Indeed, it appears that many people can, at least for a while, “get away with” bad habits and not become obese, but the trends towards increasing obesity as they move into middle age would suggest that for most people the bad habits eventually catch up with them.

    Among those for whom obesity comes faster and earlier, due to unfortunate genetics and/or environments, behaviour is still a proximal cause of disease (obesity) onset, and still a potential target of intervention. This is not to suggest that simply telling them to eat less and exercise more is likely to be effective, but simply that if those individuals worked on improving eating and physical activity habits that they would benefit, losing some weight and decreasing the comorbidities associated with their weight.

    Behaviour is important in understanding and treating obesity. The causes of behaviour are no doubt complex, as you point out.

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  3. “So if behaviour (not moving enough) is touted as one of the root causes of obesity, why does not 95% of the population have obesity?”

    The common argument to this is that the rising obesity rates show that soon it will happen!

    Hyperbole. It’s not just for breakfast anymore! (*burp*)

    As for patients educating doctors, I’m gonna be a broken record (again [again]) 🙂 and encourage that doctors have their noses rubbed in the Rudd Center’s stuff about weight bias in medicine.

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