Yes, Obesity Is a Disease

Obesity has been classified as a disease by the American Medical Association since 2013.
Image Credit: Don Farrall/Photodisc/GettyImages

In 2013, the American Medical Association (AMA) made headlines around the world with its decision to officially recognize obesity as a disease. At the time, a board member said this distinction would "help change the way the medical community tackles this complex issue," reported ​The New York Times.


The AMA was not the first medical organization to support the idea that obesity is an actual disease, rather than simply a lifestyle choice or a consequence of behavior. The National Institutes of Health had made a similar declaration in 1998, for example, as did The Obesity Society in 2008.

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But because the AMA was seen as the most influential medical society in the United States, "their statement is expected to have a significant influence on health care policy, through effects on insurers, industry, and lawmakers," wrote Kansas City–based endocrinologist Howard Rosen, MD, in ​Missouri Medicine​'s March-April 2014 edition.


At the time, the decision to label obesity as a disease was somewhat controversial. In fact, the AMA board overruled an expert panel that had advised against this recognition.

Read more:The Long-Term Effects of Obesity on Health

Now, years later, there's more consensus among health-care professionals that obesity is, indeed, a disease. New studies and an increased understanding of how obesity works have also backed up this idea, says Steven B. Heymsfield, MD, president of The Obesity Society and professor of metabolism and body composition at the Pennington Biomedical Research Center of the Louisiana State University System.


But there's still a gap between the idea of obesity as a disease and the way that society — and even medical professionals — talk about and treat people with the condition. And even today, not everyone agrees that this distinction was a helpful one. Here's where things stand now, why it matters and what experts say still needs to change.

What Makes Obesity a Disease

When The Obesity Society declared obesity a disease back in 2008, it cited several reasons for its decision. First, there was no widely accepted definition for the term "disease," which meant the distinction would have to be more of a social- and policy-driven one than a scientific one.


Second, there was a "clear and strong majority" among respected medical groups that already believed obesity was a disease, according to the society's white paper, published in the journal ​Obesity​ in September 2012.


And third, a panel of experts determined that declaring obesity a disease would deliver more positive consequences to patients than negative ones, and would "benefit the greater good."


The AMA's decision in 2013 was also influenced by how it believed patients would benefit. Recognizing obesity as a disease would "reduce weight bias" and "improve health outcomes for millions of individuals," said Ethan Lazarus, MD, a delegate for the Obesity Medical Association, in a press release about the announcement. "It means that medical students and residents will receive training in what obesity is and in the best treatment approaches," he added.


In his 2014 editorial, Dr. Rosen posed the question as to whether it was a "good idea" to label obesity as a disease. "Overall, I think yes it is despite the many controversies associated with the disease designation," he wrote.

"In our society, labeling [obesity] as a disease would be expected to improve attitudes and financial support for obesity treatment," he added, and would hopefully broaden insurance coverage for patients as well as reimbursements for doctors. (When reached for comment in October 2019, Dr. Rosen told that he still believes that designating obesity as a disease was, and continues to be, the right call.)


"We don't say that drowning is the human body behaving badly. We say, 'Jeez, we need a lifeguard and a fence around the pool, and we need to teach people to swim and tell them when there's a dangerous riptide.' To have obesity is to be drowning in calories and misinformation and labor-saving technology."

The Argument Against Obesity as a Disease

Not everyone was on board with the AMA's 2013 announcement. At the time, the decision was slammed in the National Review as an "abdication of personal responsibility and an invitation to government meddling." And in April 2014, David Katz, MD, founding director of Yale University's Prevention Research Center, penned an editorial in Nature citing the decision as "well-intentioned" but "misguided."



Today, Dr. Katz says he still agrees with this view. "I actually would double down on the position I took five years ago," Dr. Katz tells "My concern was that calling obesity a disease says that this is a problem with our human physiology — that this is is about hormones out of whack and people needing drugs or surgery."

The disease distinction overlooks the fact that many Americans overdo it on salt and sugar, he says, and that people today are far more sedentary than they used to be. All of these issues are major contributors to obesity, he says, and to related conditions like diabetes and heart disease.

Dr. Katz argues that rather than calling obesity a disease, experts should speak about obesity the way they speak about drowning. "We don't say that drowning is the human body behaving badly," he says. "We say, 'Jeez, we need a lifeguard and a fence around the pool, and we need to teach people to swim and tell them when there's a dangerous riptide.'

"To have obesity is to be drowning in calories and misinformation and labor-saving technology," he continues, "and we need societal and cultural and environmental defenses to stop it — we don't need to pretend that our bodies are at fault and that those other forces don't exist."

What’s Happened Since 2013

In December 2018, The Obesity Society released a new statement on this topic, recommitting to its initial position published in 2008. In the updated statement, the authors cite a "large and growing information database from which to characterize the disease of obesity," and they note that "many reviews by individual authors and societies provide extensive documentation of the underlying causes and consequences of obesity."

The updated position statement also points out that, over the last decade, more than 20 medical associations around the world have published their own position statements recognizing obesity as a disease.


"There is still some controversy," Dr. Heymsfield, who co-wrote the new statement, tells "But on the whole, the number of really serious professional organizations defining obesity as a disease has increased substantially over time."

Scientific studies have continued to support the idea that obesity is about more than just diet and exercise, as well. This began in the 1980s and 1990s, when scientists discovered that between 40 and 70 percent of body-size variation was due to genetic factors, according to a 2014 article published in ​Nature​.

But research in the last decade has provided an even better understanding about how, exactly, DNA plays a role in unhealthy weight gain. In a 2014 study published in The BMJ, for example, researchers found that a link between fried food and obesity was stronger in people with certain genes.

Other recent studies have found that changes to DNA in early childhood or even before birth — changes that may be brought on by a parent's diet or lifestyle choices—can also affect a person's likelihood of having obesity, according to the Harvard T.H. Chan School of Public Health.

Read more:The 6 Best Workouts if You're Genetically Prone to Obesity

"The evidence gets stronger and stronger that there's not only a heritable component, but that this component interacts with an environment that promotes obesity," says Dr. Heymsfield. "If you've got that combo — if you live in America today and you have a genetic predisposition to obesity — it almost guarantees that you are going to be affected."

Then there's the way that we talk about people who have overweight or obesity. While person-first language has become the preferred way to refer to people with chronic diseases and disabilities ("a person with diabetes," for example, rather than "a diabetic person"), it has been slower to catch on in the context of weight.


A commentary published on Medscape in July 2014 points out that, while the practice has been adopted by scientific journals and leading obesity organizations, it's often not the norm when articles in the media or even medical professionals refer to people with obesity.

"The evidence gets stronger and stronger that there's not only a heritable component, but that this component interacts with an environment that promotes obesity. If you've got that combo — if you live in America today and you have a genetic predisposition to obesity — it almost guarantees that you are going to be affected."

Has the Label Helped Patients?

When obesity was first described as a disease, some critics worried that the distinction would reinforce the idea that there was something wrong with people who have overweight or obesity. But Dr. Heymsfield believes that the disease distinction has actually helped ​reducefat shaming and stigma.

"There's still a very large contingent of people who are normal weight who believe obesity is a problem of willpower — that if you can't control your eating, you should be ashamed of yourself and your weight," he says. "But by educating people that it's not that simple, and that there are many other factors involved, we've been able to change some of those beliefs."

Dr. Heymsfield thinks the designation of obesity as a disease has also had a positive effect on the quality of care patients are receiving. "One change I've seen is the number of doctors and medical professionals going into the speciality of obesity medicine," he says. Indeed, 2019 saw a 27 percent increase in physicians becoming certified in the field, according to the American Board of Obesity Medicine, bringing the total to more than 3,000 in the United States and Canada.

Read more:6 Things You Should Never Say to Someone Who's Losing Weight

"It's starting to be the case — and eventually it may be like this in every city and town — that you can go see a specialist who knows this topic well and adheres to a certain set of standards," says Dr. Heymsfield. "It's certainly not a tsunami, but I think the needle is moving gradually and it's bringing a real benefit to patients."

But the field of obesity medicine is still relatively new, he admits. And it needs more public-relations efforts to communicate to laypeople what obesity really is, how it affects health and how to fight it, he adds.

"There's a lot of poor information out there about the latest diet or exercise trends," he says. "But none of that is going to be transformative, and all it does is distract from the really hard job of maintaining a healthy weight for a lifetime."

Meanwhile, Dr. Katz says he's surprised at how little has changed since the AMA's distinction in 2013. "I have not discerned any major impacts on patients, positive or negative, in the way they are perceived nor in the way they are treated," he says. The classification of obesity as a disease also has not led to a sudden burst of effective new treatments, he adds, as some people had hoped.

"Frankly, we're not going to get drugs to fight obesity anytime soon for the same reasons we're not getting drugs to help people breathe underwater," he says. "Because we're adapted to breathe air, just like we're adapted to survive in a world where calories are restricted and our food varieties are limited — unlike the world most of us live in today."

Dr. Heymsfield agrees that, no matter how we classify the obesity epidemic, dramatic cultural shifts are needed in order to stop it. "Very few societies over the last 1,000 years have had such a bountiful abundance of food and a lack of the need to run after it and catch it," he says. "And because of that, our bodies have very weak defense mechanisms against weight gain, and very powerful ones against weight loss."

Read more:The Best Tips for Every Stage of Your Weight-Loss Journey




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