The Controversy Over Obesity as a Disease: What Psychiatrists Should Know

by sylvia r. karasu, m.d.

Recently, the AMA House of Delegates voted to classify obesity officially as a disease, and in doing so, it has discarded the recommendation by its own panel of experts from the Council on Science and Public Health. Furthermore, as a result, the more than one-third of American adults who are obese now have a recognized disease (Psychiatric News, July 19).

Years ago, obesity was considered a moral issue: after all, two of Christianity’s Seven Deadly Sins are gluttony and sloth. Over the years we have shifted from the moral to the medical and have “medicalized” obesity.

The controversy over whether obesity qualifies as a disease (rather than a risk factor for other diseases, such as cardiac or metabolic abnormalities) is not new and touches on the very fabric of medicine, namely, what exactly is a disease? Though there are definitions that physicians use, the answer is not an obvious one. In fact, the council report says, “This seemingly straightforward question lacks a single, clear, authoritative, and widely accepted definition.” It continues, “Indeed, the medical community’s definitions of disease have been heavily influenced by contexts of time, place, and culture, as much as scientific understanding of disease processes.”

Obesity, the medical term, is an excess accumulation of fat, or in medical parlance, adipose tissue. Other than this excess of fat, though, there are no other clinical signs or symptoms that are present in all obese people. Obesity, as defined today, is determined by a ratio made popular in the 1970s—the body mass index (BMI), or the weight in kilograms divided by the height in meters squared. As such, as noted by Rockefeller University researcher Jeffrey Friedman, M.D., it is a “threshold concept.”

In other words, although the higher the BMI, the more likely significant medical morbidity and even mortality, the actual BMI cutoff for obesity is fairly arbitrary and statistical, rather than diagnostic. By changing our cutoff number, we can create an entire new population of ill people and dramatically change the prevalence of obesity in any population. In fact, it was not until the late 1990s that the World Health Organization provided the guidelines we use today. BMI, though, is a highly flawed and notoriously inaccurate clinical measure of obesity. It measures bone and muscle as well as fat, and it is inaccurate in particularly muscular people such as athletes and in unusually tall or short people. It has become popular, though, because it is safe, economical, and convenient.

One of the other complications of viewing obesity as a disease is that there are some obese people who never develop medical problems and live long and healthy lives. These fortunate individuals have so-called metabolically benign obesity. Physicians are not necessarily able to predict which patients are most susceptible to obesity-related diseases, of which there are many, including some forms of cancer, heart disease, diabetes, abnormal lipid levels, osteoarthritis, sleep apnea, and so on. Perhaps David B. Allison, M.D., the Quetelet Endowed Professor of Public Health at the University of Alabama at Birmingham, and his colleague Stanley Heshka, M.D., summarized the controversy most efficaciously, “We are therefore placed in the conceptually awkward position of declaring a disease, which, for some of its victims, entails no affliction.”

Significantly the International Classification of Diseases (ICD-9), as well as the forthcoming ICD-10, has listed obesity, in the "Endocrine" section, among its diseases. And although considered for acceptance in the recently published Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the DSM-5 Task Force opted not to include obesity as a psychiatric disorder. The report of the AMA’s council presented the pros and cons of “medicalizing” obesity. On the one hand, doing so “could intensify patient and provider reliance on pharmacological and surgical treatments” and lead to “prioritizing body size as a greater determinant of health than health behaviors” and even lead to “overtreatment” for some. On other hand, recognizing obesity as a disease may lead to decreased stigma and discrimination experienced by the obese in our society and may also lead to increased financial reimbursement for obesity-related treatments. There is no question that obesity is a major public-health concern for adults and children worldwide. By the latest statistics (from the Centers for Disease Control and Prevention), over 78 million adults (41 million women and 37 million men) in the United States are obese, as are 17 percent, or about 12.5 million U.S. children and adolescents. Over the past 30 years, obesity rates have been increasing for reasons that are not completely clear but are the result of a complex combination of genetic, environmental, and behavioral factors. Some researchers believe that by 2030, over 86 percent of Americans will be overweight or obese. Whether obesity is a disease is obviously a complex and controversial one. The most important result of the AMA’s recent statement, though, is that it puts obesity front and center in the public dialogue. And if there is any hope of gaining control over our national obesity problem, it is by continuing to keep this dialogue in the public domain.

Sylvia R. Karasu, M.D., is a clinical associate professor of psychiatry at Weill Cornell Medical College in New York City. She is the senior author of The Gravity of Weight, a comprehensive textbook on the science of weight control, published by American Psychiatric Publishing. The book can be ordered here.

>>Back to Newsletter