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The classification of obesity as a disease remains a contentious issue. On one hand, recognizing obesity as a disease highlights its serious health implications, complex biological mechanisms, and significant economic burden. On the other hand, it challenges traditional definitions of disease and may have negative social and psychological effects. Ultimately, the decision to classify obesity as a disease should consider both the scientific evidence and the potential impact on public health strategies and individual behaviors.
Obesity has become a prevalent issue worldwide, raising significant health and economic concerns. The debate on whether obesity should be classified as a disease has garnered attention from both the medical community and the public. This article aims to explore the arguments for and against classifying obesity as a disease, examining its impact on health, the underlying mechanisms, and the implications of such a classification.
The Case for Obesity as a Disease
Health Implications
Obesity is associated with numerous comorbidities, including diabetes mellitus, coronary heart disease, certain cancers, and sleep-breathing disorders1 2 5. The condition significantly increases the risk of developing these diseases, leading to higher morbidity and mortality rates. For instance, a body mass index (BMI) above 35 kg/m² increases the risk of diabetes mellitus by 93-fold in women and 42-fold in men5. Additionally, obesity contributes to cardiovascular diseases, hypertension, and dyslipidemia, further exacerbating health risks7.
Biological Mechanisms
Obesity is a complex, multifactorial disease influenced by genetic, epigenetic, and environmental factors2 6. The expansion of adipose tissue and visceral fat leads to metabolic disorders, organ dysfunction, and increased mortality8. The chronic nature of obesity, coupled with its potential reversibility through appropriate diagnosis and treatment, supports its classification as a disease8.
Economic Burden
The economic impact of obesity is substantial, with costs related to excess weight reaching 9.3% of the U.S. gross domestic product8. Recognizing obesity as a disease could lead to better resource allocation for prevention and treatment, ultimately reducing healthcare costs and improving patient outcomes8.
The Case Against Obesity as a Disease
Definition of Disease
Critics argue that obesity does not fit traditional definitions of disease, which typically involve a universal set of symptoms or signs and impairment of function4. While obesity is a significant threat to health and longevity, it lacks a consistent group of symptoms that characterize other diseases4. Labeling obesity as a disease may be seen as an expedient measure rather than a scientifically sound classification4.
Social and Psychological Implications
Labeling obesity as a disease could have unintended consequences on weight-management processes. Studies have shown that defining obesity as a disease may undermine self-regulatory processes, leading to decreased concern about weight and higher-calorie food choices among obese individuals9. While this classification may improve body image, it could also reduce the emphasis on health-focused dieting and weight management9.
Is obesity a disease?
E L Gibson has answered Likely
An expert from University of Roehampton in Nutrition, Psychology
In 2013, The American Medical Association, and subsequently several other medical bodies including the National Institutes of Health, decided to classify obesity as a disease. So if you are American, presumably so far as your medical insurance is concerned, obesity is a disease, which might have implications for the way an obese person is treated. But of course the issue is more complicated, not least if you are not American.
When people think of a disease, they often think of illnesses that are infectious, even contagious, like measles; but obesity is a ‘non-communicable’ disease (NCD), i.e. it cannot be transmitted between people (except socioculturally or genetically), like cardiovascular disease, which is hidden, or insidious conditions where deterioration is obvious such as dementia. This aspect may mean some people are uncomfortable with seeing obesity as a disease; moreover, unlike most infectious diseases, NCDs including obesity, often have multiple causes, manifestations and comorbidities.
But to answer the question more thoroughly, we need to understand what ‘obesity’ is. Technically, obesity is defined by a body mass index (BMI; weight in kg divided by height in metres squared) of at least 30; yet even this definition needs to modified if the person is Asian (lowered considerably, depending on ethnicity) because of ethnic differences in the ratio of fat mass to fat-free mass and susceptibility to Type-2 diabetes. This classification is based on BMI being a (rough) proxy for excess fat mass, and increased risks to health by conditions like Type-2 diabetes, as well as increased mortality. As well as diabetes, excess body fat is associated with increased blood pressure, cardiovascular disease, endocrine disturbances including reduced fertility, sleep apnoea, increases in some cancers, joint problems, gout, gall stones, increased risk of dementia, to name a few. So at the very least, obesity is a condition that increases risk of a range of diseases, many of which increase the chances of premature death.
So are there any downsides to classifying obesity as a disease? Well, perhaps the most obvious problem is the crude measure, BMI, used to classify obesity. For example, a heavily muscled man with little body fat could easily have a BMI > 30, but would not benefit from being labelled obese. By and large, apart from the mechanical stresses of excess weight, the comorbities are most strongly associated specifically with abdominal fat, which can be fairly well measured by waist circumference. However, since taller people on average have larger waists, a more predictive measure of health risks is waist to height ratio, where having a waist larger than half your height is associated with increased risks to health, and more accurately than BMI. Would it help to dispose of obesity as a term and refer to the disease of ‘central roundness’ instead? Probably not, despite being more medically relevant.
Another risk of the disease label is that it could induce a sense of agency or inevitability that might deter some people from changing their behaviour, which invariably they need to, even if that change is hastened along by gastric bypass surgery. Talking of which, another potential downside is that there are simply too few expert centres for treating obesity to deal effectively with the extent of this ‘new’ disease. Nevertheless, with most States in the USA having at least one in three adults with BMI > 30, and some Middle Eastern and other countries making the USA look slim by comparison, anything that starts to focus medical minds and money on treating obesity, or at least ‘central roundness’, more seriously is surely a good thing?
Is obesity a disease?
Michael Vallis has answered Likely
An expert from Dalhousie University in Psychology, Obesity
This is a great question and the source of much confusion and not an insignificant amount of debate. It is, safe, however, to conclude that the medical community consider obesity as a disease, in the same way hypertension, hypercholesterolemia and type 2 diabetes are chronic diseases. The best evidence for this position is the evidence that fat cells are not inert, they just don’t sit there doing nothing, they are active endocrine organs that secrete peptides that contribute to disease; further fat deposits in the liver cause NAFLD (nonalcoholic fatty liver disease). So we view obesity as a condition for which dysfunction in health, function and quality of life are addressed.
This position has been taken by the World Health Organization, The Canadian Medical Association, and others. A recent position paper by the World Obesity Federation (Obesity Reviews 18, 715–723, July 2017) details why obesity qualifies as a chronic disease. A further paper by the American Association of Clinical Endocrinologists/American College of Endocrinology (Endocrine Practice Vol 23 No. 3 March 2017 ) have preposed the term Adiposity Based Chronic Disease (ABCD) to address some of the confusion in this issue.
Is obesity a disease?
Joreintje D Mackenbach has answered Near Certain
An expert from Independent in Epidemiology
In May 2017, the World Obesity Federation released a position statement in the journal Obesity Reviews recognising obesity as a “chronic, relapsing, progressive disease process.” This view is in accordance with the positions taken by the World Health Organization in 1997 and the American Medical Association in 2013.
As described by Bray et al. (Obes Rev 2017): “Obesity is viewed from an epidemiological model, with an agent affecting the host and producing disease. Food is the primary agent, particularly foods that are high in energy density such as fat, or in sugar‐sweetened beverages. An abundance of food, low physical activity and several other environmental factors interact with the genetic susceptibility of the host to produce positive energy balance. The majority of this excess energy is stored as fat in enlarged, and often more numerous fat cells, but some lipid may infiltrate other organs such as the liver (ectopic fat). The enlarged fat cells and ectopic fat produce and secrete a variety of metabolic, hormonal and inflammatory products that produce damage in organs such as the arteries, heart, liver, muscle and pancreas. The magnitude of the obesity and its adverse effects in individuals may relate to the virulence or toxicity of the environment and its interaction with the host. Thus, obesity fits the epidemiological model of a disease process except that the toxic or pathological agent is food rather than a microbe.”
Is obesity a disease?
Carl Lavie M.D. has answered Unlikely
An expert from John Ochsner Heart and Vascular Institute in Obesity, Cardiovascular Disease, Cardiology, Public Health, Medicine
Obesity is a diagnosis and a disorder and certainly a risk factor, but generally most do not consider it to be a disease. In a similar way, high cholesterol is generally not considered a disease.
Currently 39.6% of adults over age 20 in the US have a BMI in the obesity range, but it would be hard to classify all as having a disease. Likewise, low levels of fitness is also a bad prognostic sign, worse than obesity as we have published , but this is a risk factor, risk marker, but most would not consider it a disease by itself. In fact, a thin person who is unfit has a worse prognosis than an obese person who is fit. Additionally, although many obese have bad lipids , blood pressure, inflammation, high sugars etc, but many obese are completely metabolically healthy. In this case, if a metabolically healthy obese person also has good fitness, they really have an excellent prognosis. Therefore, in general, obesity should not be considered to be a disease.
However, when obesity becomes more severe, such as BMI over 40, which is also called Class III obesity ( or previously called “morbid obesity” ) is hardly ever healthy, and I do think at this severe degree , one would more likely think of this as a disease. I would compare this to elevated blood sugar -when 100-125, it is called impaired fasting glucose, which is a diagnosis and risk factor, but most do not count this as a disease. However, once the blood sugar reaches 126 and higher, the diagnosis is diabetes, which is considered a disease. I believe these same points apply to Obesity.
Is obesity a disease?
D J Barr-Anderson has answered Near Certain
An expert from University of Minnesota in Obesity
Yes, obesity is a disease. See more information from the American Medical Association and the peer-review literature:
https://www.ama-assn.org/sites/default/files/media-browser/public/about-ama/councils/Council%20Reports/council-on-science-public-health/a13csaph3.pdf
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4988332/
Is obesity a disease?
Dylan D Thomas has answered Near Certain
An expert from Boston University in Endocrinology
recognized as such by AMA, WHO, and most major medical societies and organizations
Is obesity a disease?
Daniel J Hruschka has answered Unlikely
An expert from Arizona State University in Epidemiology, Anthropology, Global Health
What counts as a “disease” depends on a societal notions of what is abnormal, dysfunctional, and morally wrong. So whether obesity is a “disease” depends to some extent on the society one lives in.
That said, there is good evidence that extremely high levels of fat can lead to other disorders like diabetes and heart disease. So obesity is very likely a risk factor for other conditions defined as diseases in modern medicine. But whether obesity is itself a disease, may be a question that is impossible to answer.
For that reason, my response of “unlikely” means it completely depends on one’s definition of obesity and of the societal context one lives in. If we use the WHO cutoff of BMI > 30 to define “obesity”, then there are many people who fit in this category who live very long happy lives without any indication of a “disease.”
Is obesity a disease?
Sylvia Santosa has answered Near Certain
An expert from Concordia University in Obesity
The American Medical Association and the Canadian Medical Association have recognized obesity as a chronic medical disease. Recognizing obesity as a disease is important in enhancing awareness, research, prevention, and treatment of obesity.
Is obesity a disease?
Igho J Onakpoya has answered Unlikely
An expert from Oxford University in Obesity
Although obesity is a risk factor for several other medical conditions, being obese in itself should not be classified as a disease.
Obesity is a modifiable lifestyle factor and is the result of an imbalance between caloric intake and energy expenditure. This is akin to cigarette smoking being linked to lung cancer: are we now going to classify smoking as a disease?
The burden of obesity can be reduced if effective preventive policies are put in place and allowed to flourish.
Is obesity a disease?
Daniel W Nixon has answered Near Certain
An expert from Morehouse School of Medicine in Breast Cancer
Obesity is an increasingly serious problem in the US and worldwide. Defining obesity is controversial because of debate about the definition of “disease”. Growing evidence, however, implicates causative genetic, environmental, and biological influences on body weight, leading several national and international health organizations to agree that obesity is a disease. It is clear that obesity can cause mental distress, skeletal issues from excess weight bearing and importantly is a significant risk factor for cardiovascular disease, diabetes, Alzheimer’s disease and cancer. Biological factors show that body fat is not just an inert repository of excess calories, but actually functions like a gland, producing many biological substances including leptin and adiponectin. These two chemicals are directly implicated in cancer and Alzheimer’s disease. So, obesity is a direct cause of certain disorders and is a strong risk factor for others. This leads me to agree that obesity is almost certainly a disease.
Is obesity a disease?
Nouf Sahal Alharbi has answered Near Certain
An expert from King Saud University in Public Health, Political Science
Obesity is one of the risk factors that lead to many chronic disease like T2DM