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Is Obesity Really a Disease?

Calling obesity a disease—or not—is fraught with difficulties.

Key points

  • In 2008, The Obesity Society stopped short of calling obesity a disease.
  • Discoveries regarding the genetic contribution to obesity have highlighted the complexity of obesity.
  • Calling obesity a disease affects attitudes, treatment, health insurance, policy, and education.
Source: aykut karahan/iStock
Source: aykut karahan/iStock

Recent developments in the news have once again highlighted controversies that come along with defining obesity as a disease. Most notably, several drugs currently being used to treat type II diabetes have been found to promote weight loss in obese individuals when prescribed in higher doses. Unfortunately, these drugs come at a high cost, which insurance companies are reluctant to pay.

While type II diabetes has long been recognized as a disease with a specific cause and specific disease processes, obesity is not so clear-cut.

How They Are Different

In 2008, The Obesity Society came out with a white paper on the topic of whether obesity is a disease.

At the time, they focused on the difficulties inherent in defining obesity as a disease. Apparently, there are way too many ways to become obese and too many possible outcomes for it to be called a disease. In addition, they noted a lack of a clear, widely accepted definition of disease. After reviewing the evidence and discovering it to be controversial and complex, the authors admitted to taking a utilitarian approach.

They felt that, in spite of the complexities, there were many societal and individual advantages to calling it a disease. To circumvent some of the problems, they modified the question from, “Is obesity a disease?” to “Should we consider obesity a disease?”

The difference is subtle but important. Rather than try to show why obesity is a disease using established definitions of disease, they cast a wider net. For them, obesity can be considered a disease, even though is not really a disease in the strict sense.

It should be noted that since then, health organizations like the US Food and Drug Administration, the World Health Organization, the World Obesity Federation, and even the Internal Revenue Service have taken the position that obesity is a disease.

The Role of Genetics

At the time, The Obesity Society did not have enough specifics to be able to include genetics in consideration of their findings.

The year 2008 marked the discovery of the FTO gene (fat mass and obesity–associated gene), which was heralded as the discovery of the first gene contributing to common forms of obesity.

In 2013, The American Medical Association came out with a position paper that declared obesity a disease. Between 2008 and 2013, there had been an explosion of research indicating discovery of many potential gene variants that could potentially lead to a tendency to become obese.

One would think that these discoveries would support the argument that obesity is a disease with its own unique processes. But, actually, genetics has evolved so quickly that the waters have become muddied with a plethora of potential contributors to obesity.

So, even if The Obesity Society’s declaration had been bolstered by genetic discoveries, their stance would probably have been the same.

What They Concluded

As The Obesity Society indicated, obesity can be considered a disease.

In their view, the positive ramifications of this are the following:

  • It describes obesity as a complex condition with many causes, including many factors that are largely beyond an individual’s control.
  • Obesity causes much suffering.
  • Obesity contributes to ill health, impaired function, reduced quality of life, serious disease, and greater mortality.
  • Successful treatment, although difficult, produces many benefits.
  • There is a great deal of social stigma and discrimination for those who are obese.
  • Obese people deserve better.

It is difficult to disagree with these findings.

Pros and Cons to the Disease Model

On the negative side:

  • Obese people may throw in the towel and not try to improve their health.
  • Controversies still rage regarding the nature of disease and the effect of genetics.
  • If obesity is a considered a disease, companies who contribute to health insurance costs may end up having to pay more, which could contribute to discrimination of obese people in the workforce.

On the plus side:

  • It may be easier to get funding for research. (If obesity is a disease rather than just a risk factor.)
  • There may be more insurance payments to doctors who treat obesity.
  • There could potentially be more insurance payments for anti-obesity drugs.
  • There may be less stigma and discrimination attached to being obese.

Other Difficulties to Sort Out

As noted above, it is difficult to get insurance companies to pay for what are promising new drugs for weight loss. This is just one example of struggles to get insurance to cover treatments for obesity.

Medicare and Medicaid do not cover weight-loss drugs.

It needs to be pointed out that lifestyle interventions, while complex and difficult to provide, have been shown again and again to be effective for weight loss and overall health, even in the face of genetic tendencies. Still, it needs to be recognized that behavior is only a part of the picture.

Environment is still a huge factor. One notes that the obesity epidemic closely follows the rising occurrence of our “obesogenic” environment, including highly processed foods and sedentary lifestyles. This means that the genes we carry have been enabled to express themselves more easily as our environment has changed. We need to keep awareness of this in the forefront and do what we can to pressure food manufacturing companies to create healthier options.

Finally, it seems that we need to double down on education, for the general public, doctors, and corporations, so that there is a clear message about the causes of obesity and what we can do to mitigate the suffering that obesity causes in our society.


TOS Writing Group: Allison, D.B., et al. (2008). Obesity as a Disease: A White Paper on Evidence and Arguments Commissioned by the Council of The Obesity Society. Obesity. 16:1161-1177.

Loos, R.J.F. and Bouchard C. (2008). FTO: the first gene contributing to common forms of human obesity. Obesity Reviews. 9:246-250.

DeLorenzo, A., Gratteri, S., Gualtieri, P., Cammarano, A., Bertucci, P., DiRenzo, L. (2019). Why primary obesity is a disease? Journal of Translational Medicine. 17:169.

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