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February 8, 2017

Why Is Obesity a Disease?

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]The American Medical Association (AMA) designated obesity a disease in 2013 and as a result, the idea that obesity is caused by insufficient willpower, lack of discipline, and bad choices began to transform. The headlines, “AMA Recognizes Obesity as a Disease” were catapulted across both academic and mainstream media. Obesity was no longer a conversation topic tucked away in a dusty corner but was instead sprinkled across national news for the public to scrutinize. From “TED Talks” to The New York Times, obesity specialists were asked to “weigh in” on this groundbreaking and somewhat controversial topic and to answer the question, “is obesity a disease?”

Now, four years later, the debate continues. Is obesity a disease? For some, obesity as a disease invalidates the importance of discipline, proper nutrition, and exercise and enables individuals with obesity to escape responsibility. For others, obesity as a disease is a bridge to additional research, coordination of effective treatment, and increased resources for weight loss.

According to Merriam Webster, a disease is “a condition . . . that impairs normal functioning and is typically manifested by distinguishing signs and symptoms.” In defining obesity specifically, one of the most comprehensive definitions is provided by the Obesity Medicine Association in the Obesity Algorithm. Obesity is defined as a “chronic, relapsing, multi-factorial, neurobehavioral disease, wherein an increase in body fat promotes adipose tissue dysfunction and abnormal fat mass physical forces, resulting in adverse metabolic, biomechanical, and psychosocial health consequences.”

Individuals with obesity have an increased accumulation of fat not always attributable to eating too many calories or lacking physical activity. Individuals with obesity experience impaired metabolic pathways along with disordered signaling for hunger, satiety (the feeling of fullness), and fullness (the state of fullness). For many, efforts to lose weight are met with unyielding resistance or disappointing weight regain. This is demonstrated by the follow-up body composition results of contestants on “The Biggest Loser.” As contestants lose even as much as 230 pounds, their body’s response is a slower and less efficient basal metabolic rate. This occurs in an effort to return the body to its previous condition of obesity; it’s a counter-effort by the body that makes weight gain easier and weight loss harder.

The pathology of obesity is vast and varies based on the cause of weight gain. There is not just one type or cause for obesity. Obesity sub-types include congenital, stress-induced, menopause-related, and MC4R-deficient, to name a few. Obesity is related to genetic, psychological, physical, metabolic, neurological, and hormonal impairments. It is intimately linked to heart disease, sleep apnea, and certain cancers. Obesity is one of the few diseases that can negatively influence social and interpersonal relationships.

Why obesity is a disease is becoming more evident as we increase our knowledge of fat mechanics. To successfully confront the obesity pandemic will require attacking the disease and its manifestations, not just its symptoms.

Do you consider obesity a disease? At the end of this Medscape article, you can take a short survey and view the results to find out where you stand compared to other physician specialties.

Frequently Asked Questions

Is obesity a disease or a disorder?

Obesity is a chronic disease. According to the Centers for Disease Control and Prevention, obesity affects 42.8% of middle-age adults. Obesity is closely related to several other chronic diseases, including heart disease, hypertension, type 2 diabetes, sleep apnea, certain cancers, joint diseases, and more.

Is obesity considered a chronic disease?

Yes. Obesity, with its overwhelming prevalence of 1 in 6 adults in the U.S., is now recognized as a chronic disease by several organizations, including the American Medical Association. The Centers for Disease Control and Prevention (CDC) defines chronic disease as conditions that last one year or more and require ongoing medical attention or limit activities of daily living, or both. Three leading chronic diseases are heart disease, cancer, type 2 diabetes. Obesity is associated with all three of these chronic diseases. CDC also acknowledges widespread consequences of obesity when compared to normal or healthy weight for many serious health conditions, including all causes of death, hypertension, diabetes mellitus, coronary heart disease, stroke and many cancers. Of the $3.3 trillion spent annually on medical care for chronic conditions, obesity alone is associated with $1.4 trillion.

What is the link between obesity and mental health?

Numerous studies support a strong link between obesity and mental health. This relationship appears to be bi-directional; while mental health disorders increase the risk for obesity, having obesity also increases the risk of mental health disorders, especially in certain populations. Mental health disorders can increase the risk for obesity for several reasons: 1) Medications used to treat psychiatric illnesses can cause weight gain and insulin resistance, contributing to obesity; 2) Mental illnesses affect behaviors such as decreased sleep, poor eating behaviors, and reduced physical activity, which can contribute to the development of obesity. Conversely, having obesity increases the risk for depression. This is likely due to numerous complex factors, including poor self-image and depressed mood in response to weight bias and stigma, decreased activity due to joint and back pain associated with excess weight, and biological disruptions caused by chemicals secreted by fat cells when a person has obesity. The link between obesity and mental health is complex and multi-faceted. It is important that patients with mental health disorders are monitored for weight, and that people with obesity are screened for mental health disorders.