Obesity As a Disease: Understanding the Science and Reducing the Stigma

More than 40% of Americans over 20 live with obesity and another 30% are overweight. Despite its pervasiveness, obesity is highly stigmatized, and studies show that weight stigma has profound implications across all facets of society because it continues to be associated with poor dietary choices and lack of control. The truth, however, is that obesity results from multiple complex genetic, environmental, and behavioral factors. In 2013, the American Medical Association (AMA) House of Delegates voted to recognize obesity as a disease subject to treatment and prevention efforts. Though the decision was controversial at the time, the AMA’s purpose was to enable increased funding for obesity research and treatment options, and to improve treatment outcomes. The decision would also improve insurance coverage for obesity treatment and increase reimbursement to providers for treating individuals with obesity. In this article, we’ll discuss the implications of calling obesity a disease, discover what, if anything, has changed since the 2013 AMA decision, and explore steps to reduce the stigma associated with overweight and obesity.

What Do We Mean by “Obesity” and “Disease”?

Medical organizations, clinicians, and scientists have been unable to agree on either a standard definition of obesity or whether obesity even fits the description of a disease. Currently, the most widely used tool for assessing obesity is Body Mass Index (BMI), a measure of body fat. A BMI of 25-29.9 is considered overweight. A BMI >30 is considered obese. Yet, BMI is limited in its ability to accurately assess the health risk, or impact, associated with body fat. Therefore, many argue that BMI is a poor instrument to define obesity. Some of the reasons are noted below.

Factors that limit the usefulness of BMI include:

• BMI does not differentiate between lean body mass and fat body mass. In population-based studies, women generally have lower BMI scores than men, even though their fat mass relative to BMI is greater. One study used bioelectrical impedance to measure body fat in male and female subjects, all with a BMI of 25. Men’s body fat ranged from 14%-35% due to higher lean body mass and women’s ranged from 26%-43% due to higher fat body mass. The diversity among body fat scores, from low-normal to obese, reveals the weakness of using BMI to define obesity.

• BMI does not account for fat distribution, a key indicator of obesity-associated risk. Fat stored around the abdomen carries a higher risk for heart disease, diabetes, and stroke, compared to fat stored in other locations. Waist circumference, waist:hip ratio, dual energy X-ray absorptiometry (DEXA), and computed tomography (CT) scans are better used to measure body fat distribution.

• BMI does not account for the health risks associated with other comorbid conditions, such as hypertension, diabetes, and heart disease, nor does it account for family history. A 2010 study found that genetics accounts for more than 50% of susceptibility to coronary artery disease.

• Social determinants, race, ethnicity, and age may modify the risks associated with BMI.

  
  

The weakness of BMI to define obesity complicates the matter of determining whether obesity fits the description of a disease. Yet, even if BMI effectively defined obesity, a universal definition of disease does not exist. So, how can obesity be called a disease? Organizations such as The American Obesity Society have asked this very question.

Several definitions of disease have been proposed over the years, and these definitions typically share a few characteristics.

Disease has been defined as:

• a deviation from species-typical functioning

• an organ not performing the job that allowed it to evolve by natural selection

• a condition meeting the following three conditions:

  1.  Disease is a condition of the body, its parts, organs, or systems or an alteration thereof.

  2.  The condition results from infection, parasites, nutritional, dietary, environmental, genetic, or other causes.

  3.  The condition deviates from normal structure or function.

  
  

However it is defined, obesity has reached epidemic proportion. Obesity and its complications are challenging the world’s health care systems. It is a complex condition with life-threatening outcomes if not treated. Despite the lack of a universal, clear definition for both terms--obesity and disease--the AMA decision to recognize obesity as a disease is both a compassionate and necessary step toward improving obesity outcomes and reducing the stigma associated with it.

The Case for Classifying Obesity as a Disease

Worldwide, obesity is a major public health issue associated with increased morbidity and mortality. It is a chronic condition associated with hormonal and metabolic dysregulation. According to the CDC, people with overweight or obesity are at increased risk for many serious diseases and health conditions including:

• All-cause mortality (early death)

• High blood pressure

• High or low LDL cholesterol and high levels of triglycerides

• Type 2 diabetes

• Heart disease

• Stroke

• Gallbladder disease

• Osteoarthritis

• Sleep apnea and breathing problems

• Many types of cancers

• Lower quality of life

• Mental illness such as clinical depression, anxiety, and other mental disorders

• Generalized pain and difficulty with activities of daily living

Because of its complexity, it is essential to adopt all possible strategies for combatting obesity, reducing patient suffering, and reducing the costs of obesity treatment. Currently, obesity is underdiagnosed due to the limitations of using BMI as a diagnostic tool. It is estimated that 30% of people with obesity are not diagnosed, limiting access to affordable treatment options. Correct and early diagnosis of obesity will lead to reduced healthcare costs and prevention of many of the diseases associated with it.

The Case Against the Disease Label

Some of the difficulties in labeling obesity a disease have already been mentioned: the lack of a universal definition of both obesity and disease, and the obesity paradox in which some people with a normal BMI have an excess of visceral fat and are not healthy, while others with BMIs in the obese range have better short- and long-term health outcomes.

Another argument against the disease label is that it creates social anxiety and a “fear of fatness” which often focuses on individual responsibility for obesity while ignoring uncontrollable factors, like genetics, that lead to obesity. Proponents of the Health at Every Size (HAES) philosophy believe that focusing on measures of body weight, shape, and size is unhealthy. They encourage practicing a fulfilling and meaningful lifestyle, listening to internal hunger and satiety signals, and practicing reasonable levels of exercise.

Weight-based prejudices generally attribute overweight and obesity to laziness and lack of willpower. To reduce the stigma of obesity, public awareness and education about the complexity of obesity and obstacles in achieving sustainable weight loss are needed. Societal and media messages that blame the obese person need to be replaced with messages that obesity is a disease with complex causes, many potential associated conditions, and is often a lifelong condition.

A Public Health and Social Imperative to Change Perceptions

What changes have occurred since the 2013 declaration of obesity as a disease? Has public perception of obesity changed?

While newer approaches like Health at Every Size are attempting to change public perceptions of obesity, evidence suggests that obesity rates continue to climb, while obesity stigma and bias persists. Media is a major source of weight bias through inappropriate images and language that perpetuates individual responsibility for obesity rather than recognizing the nature of the disease.

In the section above, we discussed the need for public awareness and education regarding the causes of obesity and the media’s culpability in promoting obesity bias and the personal responsibility narrative. Other targets for an education campaign include healthcare providers, the media, and the community in general.

Medical care providers can learn to use patient-first language (“person with obesity”). The media should move away from using visuals and graphics that promote a perfect body image and are shaming to overweight people. Also, community-level education campaigns can promote a neutral body image by promoting healthy eating and reasonable exercise.  

Toward Inclusive and Effective Treatment

Two guidelines are currently standard of care in the management of overweight and obesity. One results from a 2013 collaboration between the American College of Cardiology (ACC), the American Heart Association (AHA), and The Obesity Society (TOS). The second guideline results from a 2016 collaboration between the American Association of Clinical Endocrinologists (AACE) and the American College of Endocrinology (ACE). Body Mass Index continues to be recommended for an initial evaluation while other weight-related conditions help establish disease severity. Lifestyle interventions, including healthy diet and regular exercise, remain the cornerstone of treatment for obesity. Behavioral therapy can be added as needed. More successful interventions, for those who are approved, include pharmacotherapy and metabolic and bariatric surgery.

Several of the alternative options remain unavailable to those without income or health insurance. Also, people who are severely obese can require a multimodal approach. As a society, we must address the disparity in access to treatment options if we want to reduce the incidence of overweight and obesity.

A Conclusion to the Obesity Epidemic

Obesity is a complex medical disease that requires understanding rather than shame if we hope to slow or stop its rate of growth. Clinicians, the media, and policymakers must be educated about obesity and should be held accountable to make efforts in reducing the associated stigma. Social media and other methods should be used to promote positive messages and educational materials for the community. Compassion and evidence-based care are essential to support and improve treatment outcomes for individuals living with obesity.

References

De Lorenzo, A., Gratteri, S., Gualtieri, P. et al. (2019). Why primary obesity is a disease?. Journal of Translational Medicine. 17(169). https://doi.org/10.1186/s12967-019-1919-y

Fulton, M., Dadana, S., Srinivasan, V.N. [Updated 2023 Oct 26]. Obesity, Stigma, and Discrimination. StatPearls [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK554571/

Hales, C.M., Carroll, M.D., Fryar, C.D., Ogden, C.L. (2020). Prevalence of Obesity and Severe Obesity Among Adults: United States, 2017–2018. NCHS Data Brief, no 360. National Center for Health Statistics. https://www.cdc.gov/nchs/products/databriefs/db360.htm

National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Food and Nutrition Board; Roundtable on Obesity Solutions; Callahan EA, editor. (2023 Jul 31). The Science, Strengths, and Limitations of Body Mass Index. Translating Knowledge of Foundational Drivers of Obesity into Practice: Proceedings of a Workshop Series. https://www.ncbi.nlm.nih.gov/books/NBK594362/

Nuttall F. Q. (2015). Body mass index: Obesity, BMI, and health: A critical review. Nutrition Today, 50(3), 117–128. https://doi.org/10.1097/NT.0000000000000092

Penney, T. L., & Kirk, S. F. (2015). The health at every size paradigm and obesity: missing empirical evidence may help push the reframing obesity debate forward. American Journal of Public Health, 105(5), e38–e42. https://doi.org/10.2105/AJPH.2015.302552

Puhl, R. M., & Heuer, C. A. (2010). Obesity stigma: Important considerations for public health. American Journal of Public Health, 100(6), 1019–1028. https://doi.org/10.2105/AJPH.2009.159491

Rosen, H. (2014). Is obesity a disease or a behavior abnormality? Did the AMA get It right? Missouri Medicine, 111(2), 104–108. https://pmc.ncbi.nlm.nih.gov/articles/PMC6179496/

Rubino, F., Puhl, R.M., Cummings, D.E. et al. (2020). Joint international consensus statement for ending stigma of obesity. Nature Medicine. 26, 485–497. https://doi.org/10.1038/s41591-020-0803-x

U.S. Centers for Disease Control and Prevention. (2024). How overweight and obesity impacts your health. https://www.cdc.gov/healthy-weight-growth/food-activity/overweight-obesity-impacts-health.html

Assessed and Endorsed by the MedReport Medical Review Board