Is Obesity a Disease?

Is obesity a disease? This is a question I ask myself regularly and have many internal debates in my efforts to answer.

On the one hand, I want the health consequences of obesity to be taken seriously. In the spirit of The Obesity Society's "I Treat Obesity Seriously" campaign, I want people needing treatment to have access to it. I want people to have access to evidence-based, sound treatments, with plenty of options between the extremes of "just eat less" and bariatric surgery.

On the other hand, obesity is currently defined as a size. As Dr. Sharma told us at this week's Your Weight Matters Convention, anatomical descriptions of obesity don't tell us anything. By using definitions--even if they can be calculated with numbers--that ultimately rely on visual cues, I worry we further stigmatize people who have obesity.

In order to think of something as a disease--and treat it seriously, we (1) need a definition that demonstrates health impact, (2) we need ways to screen and identify individuals with a disease, and (3) we need treatments to offer them.

The CDC, and pretty much everyone else, defines obesity based on BMI. Of course, BMI doesn't distinguish fat from muscle, subcutaneous fat from visceral fat, healthy people from unhealthy. There have been some good attempts to "score" obesity in terms of health, including the Edmonton Obesity Staging System. They are huge improvements, but we don't have enough evidence to define obesity using them alone. Does my BMI-defined obesity remain "obesity" because I think Prevacid is the best drug ever invented, or do I need to have actual GERD? Is a tight airplane seat enough functional limitation, or does it have to reach the point I buy velcro shoes?

For that matter, how we are we going to implement and screen any sort of health-based measure like this? Do I have to have a high BMI? I could have high percent body fat and a low BMI. What about all of the people who have a low BMI and conditions associated with obesity? If we use size as the fundamental requirement for defining obesity, how do we get past the stigma of the current societal perceptions of size? BMI is used because it's so easy to calculate. Really identifying when a high BMI is problematic requires more effort--a fasting lipid panel, for example, along with many other assessments.

One of our greatest challenges is that there are too few treatments for obesity. Intensive lifestyle interventions can work, but they don't always, and they aren't readily accessible to everyone. There are a few new drugs, but pharmaceutical treatment continues to struggle to overcome the black mark of Phen-Fen. Obesity treatment research is painfully hampered by the perception that obesity is the fault of the person with the obesity. The unremarkable success of current treatments has led to a focus on prevention, assuming treatment will never work. But we don't know that treatments won't work--we just haven't found them yet. What if we stopped trying to find cancer treatments because early efforts were not successful?

The "obesity epidemic" is not something that we can solve overnight. Prevention is a key element, but until we regularly use health-focused definitions, recognize the complex factors underlying obesity, and develop effective treatments, we will never succeed. Paraphrasing Ted Kyle, we are "writing off an entire generation, perhaps two generations." And we are doing this because of our unwillingness to accept that the failure is actually our own. We researchers, clinicians, and policymakers have failed people who have obesity because it's easier to say "people just need self-control" than "we have done a terrible job defining this disease and developing treatments."

Passing the blame is simply unfair. We will only ever be able to "Treat Obesity Seriously" when we take responsibility for developing serious health-focused definitions, step away from body size stigma, and focus our energy on real, effective treatments.