Is Obesity a Disease?

The Short Answer is "Yes - it is now!"

According to the HSE’s “Obesity in Adults:  A 2022 Adapted Clinical Practice Guideline for Ireland” obesity is defined as a complex chronic disease characterised by excess or dysfunctional adiposity that impairs health.

How and when did Obesity become a disease?

In June 2013, the Membership of the American Medical Association’s (AMA’s), at its annual conference, voted, and passed, Resolution 420 which stated:


“That our American Medical Association recognize obesity as a disease state with multiple pathophysiological aspects requiring a range of interventions to advance obesity treatment and prevention.”


This vote in favour of resolution 420 took place despite (and against the contrary) Recommendation and Opinion of the AMA’s own Committee on Science and Public Health).

Milestones in Regarding Obesity as a Disease and their Policy Implications

Figure 1 depicts milestones in regarding obesity as a disease. Each milestone is an example of how labeling a condition as a “disease” or “not a disease” can have significant policy implications. Established in 1977, the Healthcare Financing Administration (HCFA, predecessor to CMS, the Centers for Medicare and Medicaid Services) included language in its Coverage Issues Manual stating that “obesity is not an illness.” This language reflected widely-held beliefs and served as a model for denying coverage of obesity care under both publicly and privately funded health plans.

In 1998, the National Institutes of Health published Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults that stated, “Obesity is a complex multifactorial chronic disease.”


In early 2002, the Internal Revenue Service issued a ruling that expenses for obesity treatment would qualify as deductible medical expenses. Later in 2002, the Social Security Administration (SSA) published an evaluation of obesity stating that “Obesity is a complex, chronic disease characterized by excessive accumulation of body fat.” This determination explicitly stated that obesity is a valid medical source of impairment for the purpose of evaluating Social Security disability claims.


A key milestone came in 2004 when CMS removed language stating that “obesity is not an illness” from its Coverage Issues Manual. Although this action did not include a specific determination that obesity is a disease, it removed a significant obstacle to further progress and coverage for obesity-related medical services.


In 2006, CMS issued a National Coverage Determination providing coverage for bariatric surgery under Medicare, a decision that followed as a natural consequence of the agency’s 2004 reassessment of obesity.


The Obesity Society published a white paper on evidence and arguments for obesity as a disease in 2008, followed in 2012 by a similar position from the American Association of Clinical Endocrinologists.


Finally, in 2013, the American Medical Association resolved at its annual House of Delegates meeting to “recognize obesity as a disease state with multiple pathophysiological aspects requiring a range of interventions to advance obesity treatment and prevention.”


Though this resolution has no legal standing, the AMA has stated that “recognizing obesity as a disease will help change the way the medical community tackles this complex issue.” Their leadership in shifting the care model for obesity to a chronic disease model may have a significant impact on the way obesity is addressed

Why did the AMA Membership vote to recognize Obesity as a disease?

The AMA’s stated reasons were as follows:


“Recognizing obesity as a disease will help change the way the medical community tackles this complex issue that affects approximately one in three Americans,” Dr. Patrice Harris, a member of the association’s board, said in a statement. She suggested the new definition would help in the fight against Type 2 diabetes and heart disease, which are linked to obesity.


The AMA’s President in 2013, Ardis Hoven, stated: “The AMA has long recognized obesity as a major public-health concern, but the recent policy adopted in June marks the first time we’ve recognized obesity as a disease due to the prevalence and seriousness of obesity.”

Were there any other reasons?

Yes. Payment.


Designating obesity as a disease increases the chances that the cost of obesity treatments will eventually be covered by private health insurance plans and national health insurance.


Doctors need to be paid for delivering weight-loss treatments to patients.  By designates obesity as a disease, it is likely in the future that wieght managment treatments (including anti-obesity drugs) will be covered by private insurance plans and national health insurance.


However, at present, most private health insurance plans (and national health insurance) do not cover the cost of any weight-loss treatment programmes (or cover the cost of weight loss drugs) – except bariatric surgery for critical patients (ie when it is a matter of life or death).


The new “Obesity in Adults: A 2022 Adapted Clinical Practice Guideline for Ireland” calls for the inclusion of obesity in the Structured Chronic Disease Management Programme and for pharmacotherapy reimbursement, to ensure equal access to treatment based on health need rather than ability to pay.