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Setting The Stage For Obesity Staging

Long-time readers of these pages may recall that in 2009, Robert Kushner and I published a proposal for a new clinical obesity staging system in the International Journal of Obesity.

Rather than BMI (a measure of weight), the Edmonton Obesity Staging System (EOSS) ranks severity of obesity based on clinical assessment of weight-related health problems, mental health and quality of life. We proposed that this system would provide a far better guide to clinical decision making than using BMI class alone.

For reasons that will become apparent later this week, I would like to repost an excerpt from this original proposal for this system, which was first posted on this blog on March 30, 2008:

Current definitions of obesity based on BMI and waist circumference (WC), while widely accepted, are hardly helpful in counseling individual patients. Readers of my blog are probably quite familiar with my views on this.

As most clinicians will readily agree, when dealing with indiviual patients, both measures lack sensitivity and specificity with regard to identifying the presence or risk of obesity-related risk factors, comorbidities, psychopathology, global functioning or quality of life.

In fact recent epidemiological studies emphasize that good health including low morbidity and mortality is possible over a wide range of BMI. Thus, basing the decision on who to treat and who to leave well alone solely on measures of weight or size is neither sensible nor does justice to the complexity of the relationship between excess body fat and its impact on health and well-being. The well-established obesity-chronic disease paradox makes decisions on who to treat and who not to treat even more uncertain.

Telling healthy large people who have no apparent comorbidities, functional limitations or reduced well-being to lose weight may be counterproductive in that it can introduce and reinforce dissatisfaction with body image, foster frustrations and despair (given the poor long-term success of weight loss attempts) and lead to unhealthy behaviours focusing on weight loss (e.g. excessive exercise or dieting) rather than on healthy lifestyles (which are possible at almost any weight).

Thus, for practical purposes, it is important to move beyond defining who needs obesity treatment simply based on BMI and/or WC to a more clinically meaningful system.

Indeed, what we direly need is a classification of obesity that is clinically relevant in that it helps identify patients who have or are at high-risk of obesity-related complications and are most likely to benefit from treatment.


Now I am no expert on disease classification and realise the large amount of work and consensus meetings that go into developing these classification systems. But I am a clinician, who regularly sees patients and would be happy to see even the simplest form of staging that provides a meaningful framework.

The simplest classification I can think of would be to use a staging system similar to the following:

Stage 0: no apparent obesity-related risk factors (blood pressure, lipids, glucose, etc.), physical symptoms, psychopathology, functional limitations, or impairment of well-being

Stage 1: presence of obesity-related sub-clinical risk factors (elevated blood pressure, impaired fasting glucose, fatty liver, etc.), mild physical symptoms (dyspnea on moderate exertion, occasional aches and pains, etc.), mild psychopathology, mild functional limitations or mild impairment of well-being

Stage 2: presence of established obesity-related chronic disease like hypertension, type 2 diabetes, sleep apnea, osteoarthritis, reflux disease, polycystic ovary syndrome, depression, anxiety disorder, moderate limitations in activities of daily living and/or well being.

Stage 3: established end-organ damage like myocardial infarction, diabetic complications, severe osteoarthritis, significant psychopathology, significant functional limitations and impairment of well-being

Stage 4: severe (end-stage?) disabilities from obesity-related chronic disease, severe disabling psychopathology, severe functional limitations and severe impairment of well-being

Thus, for e.g., a 24 year-old physically active female with a BMI of 32 with no measurable risk factors, functional limitations or self-esteem issues would have Class I, Stage 0 Obesity – benefits of treatment will be marginal or non-existent.

A 32 year-old male with BMI of 36 with hypertension and sleep apnea would have Class III, Stage 2 Obesity – definite indication for obesity treatment.

A 45 year-old female with BMI of 54 who is in a wheel chair because of severe gonarthritis with severe hypoventilaltion would have Class III, Stage 4 Obesity – will require aggressive obesity treatment unless deemed palliative.

Stay tuned for more on the Edmonton Obesity Staging System this week.

Edmonton, Alberta

Sharma AM, & Kushner RF (2009). A proposed clinical staging system for obesity. International journal of obesity (2005), 33 (3), 289-95 PMID: 19188927


  1. Okay. Let’s say I’ve got normal blood pressure and blood sugar levels, but had to have a hip replacement due to trauma induced osteoarthritis resulting from car accident injuries. Also, I’ve got some minor aches and pains related to that. Does that make me stage 0 or stage 2? Would your answer be different if my BMI was 20 vs. 40 and if so, why? Do the injuries suddenly become the result of my weight rather than the car accident if I’m heavier even if they are, in fact, a result of the car accident?

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  2. Interesting. I was part stage 1, part stage 2, and one stage 3 symptom. Two thing is absent in the staging. First is attitude of the patient. The second is …. but then I am just a ex-obese person.

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  3. @DeeLeigh: “Does that make me stage 0 or stage 2? ”

    Great question, because the answer is not clear at all. If the injury is contributing to weight gain, then pain management and physiotherapy, etc. could be indicated to prevent further weight gain.

    If despite best pain management, the osteoarthritis gets worse and mobility weight loss may be indicated (remember each lb of weight loss takes 4 lbs off each knee).

    In EOSS we have counted the presence of osteoarthritis as EOSS 2 – irrespective of cause because simply having both obesity AND osteoarthritis can increase risk (whereas obesity alone may not).

    We limit the use of EOSS to overweight and obese patients, the rationale being that in patients with lower BMI levels (e.g. 20) not only is it unlikely that weight is aggravating or contributing to the problem nor is it likely that weight loss will remarkably reduce pain or symptoms.

    Again – a great research question!

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  4. How do you rank someone who has a BMI over 50, mobility issues (osteoarthritis and back issues from a fractured pelvis years ago) but has no other co-morbidities? Blood pressure, blood sugar, cholesterol, heart, lungs are all fine, arteries are clear, no depression.
    Seems to me your ranking system leaves out a lot of people who are fat, metabolically healthy, but have physical issues for whatever reason, not all of them related to being fat. Given that there is no way to make a fat person safely, permanently thinner, what do you suggest? Weight may be aggravating those physical issues, but losing weight is not an option for most of us, been there done that, and got fatter trying, thank you very much. So far, weight loss is the only solution offered and it’s not really a viable solution.

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  5. If despite best pain management, the osteoarthritis gets worse and mobility weight loss may be indicated (remember each lb of weight loss takes 4 lbs off each knee).

    In EOSS we have counted the presence of osteoarthritis as EOSS 2 – irrespective of cause because simply having both obesity AND osteoarthritis can increase risk (whereas obesity alone may not).

    Well, I’m certainly glad I didn’t consult you. I researched it and found out that many thin people also have ruined hips 20 years after a dislocation and broken joint. Also, it was only one hip – the one that had been broken and dislocated. The other hip was fine. So, my doctor and I blamed the car accident rather than my weight, I had a hip replacement, and two years later I’m back to normal. If I’d followed your advice, I’d probably be regaining weight I’d lost on a diet and have compromised mobility right now. Instead, I’m the same size I’ve always been and can walk all day again.

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  6. The more I think about this, the more it bothers me. If you withhold a treatment like a hip replacement, telling the patient to lose weight instead, then you’re setting them up for failure. You know that most people can’t maintain a large weight loss.

    And, you’re in favor of weight loss surgery. Does this mean that you’d try to blackmail patients into weight loss surgery by refusing to approve joint replacements until they’ve lost weight? I’m really concerned about this, because I’ve heard of it happening and I think it’s unconscionable.

    Right now, I’m just thankful that my sports medicine specialist and surgeon never weighed me and probably didn’t know what my BMI was. Maybe if they had, I’d have been refused treatment. I mean, I guess I could have starved myself down to a “normal” BMI and then had the surgery, but I can’t imagine what it would have been like trying to recover while dealing with a weight rebound, and after having lost most of my muscle mass.

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  7. Hi Dr. Sharma:

    After hearing this artical on the news I went to look up “fatty liver self treatment” thinking that I would benefit from that. There was surprisingly little there that was not vested in product flogging. Then I looked up your exact article on e-mail (media is so good at over simplifying things–and this happened here also) the emphansis on other agrivating medical issues for bariatric surgery does sound reasonable. When I had my recent foot surergy (debraidment) I asked the foot doctor about loosing weight and how much I should loose, his comment was “any weight loose is good”.

    Because physical pain can interupt the REM sleep patern the well-being of a person: furthermore, there are complications with pain medications that hip replacement surgery can truly help and preventing medication problems is the better course of action.

    As I understand it the presurgery weight loose is so that there is a graeter chance of success and maintained success rather than failure. Afterall It is fairly hard for a hip replacement to produce a relapse whereas, it is quit possible for bariatric surgry to relapse.

    That being said I would like some information on how to treat fatty liver. Afterall there is self treatment for diabetis and cholesterol. It might be a case where I have taken some charge and want to take more charge of my health. The last thing I want to do is regain the 35+ pounds that I have lost as these will come back with reinforcements.

    I truly feel inpowered by loosing weight. I have even spelled the word weight enough to have it in my memory, a benefit for my ADHA spelling disability.

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  8. I have another question. Everyone who lives long enough eventually develops the chronic diseases of aging, including heart problems and (for people who are genetically prone to it) diabetes. Does this mean that thin people will redefined as obese as they age? What about fat people who develop age-related diseases at around the same time as their thin contemporaries? Are you going to blame their weight? Obviously, that makes no sense.

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  9. Hi Dr. Sharma, I’m really intrigued with this idea of an obesity staging system. It makes a lot more sense than what I usually hear, which is , OMG you weigh X, lose weight now or you will be dead by forty.

    I really question the validity of including mental illness as a staging criterion, though. I have two main concerns:

    First of all, certainly people can experience low low self-esteem and negative emotions, or develop eating disorders, stemming from unhappiness with their weight. In these cases, maybe getting down to a “desirable” weight would make them feel better (except in the case of eating disorders), until, of course, they gain it all back with more. Wouldn’t it make more sense to work on self-acceptance?

    Second, when it comes to mental illness as opposed to ordinary unhappiness, I wasn’t aware that there was the smallest scrap of evidence that obesity is involved in its causation, though there are plenty of ways mental illness can cause obesity, whether it’s self-medication with food or alcohol, loss of ability to function that leads to poor diet and low activity levels, or the many psychiatric medications that cause significant weight gain (mood stabilizers and antipsychotics are the main culprits, but some antidepressants also). Helping the patient get the mental illness better under control may improve their ability to engage in healthy behaviours, and is a good thing, but there’s zero guarantee that this will have any effect on weight.

    I haven’t been able to access the full text of the article in which you originally describe the EOSS model, but I’m assuming there are citations there to support mental illness as a staging consideration. Would it be too much trouble to email and/or post those citations and/or suggest further reading for me on this subject?


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  10. Please consider PCOS as a ’cause’ of fat instead of as a result of fatness.

    Anxiety problems can also bring on weight as a causation with higher cortisol levels.

    Endocrine disease does cause fat as a symptom.

    Us Fat people need more help that works. Also a return to the old formula of admitting some fat people have serious metabolic issues, yes there are those with food addiction etc, too. I nearly died from not having doctors listen….

    Read my story here…[I gained almost 400lbs in 2 and half years NOT by choice and have weighed nearly 700lbs, definitely near your stage 4, now hovering somewhere in stage 3 and in the low 500s [I can walk small distances and am not wheelchair bound but considering I am disabled, figure stage 3 would apply]

    Weight loss is failing too for most people, long term. That is a problem. That needs more research as well. Doctors as a whole have to do better, with weight there is something beyond just failed will power going on.

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