As global approvals of new anti-obesity medicines accelerate, drugmakers have a public service announcement for the world: “Obesity is a disease.” Eli Lilly launched a website asserting that obesity is not merely a risk factor for medical complications but a chronic and complex medical entity in its own right. Novo Nordisk, more circumspectly, appeals to institutional authority on its website: “Recognised as a disease by the World Health Organization, obesity is serious, progressive and chronic.”

It is no surprise that the new wave of obesity pharmacotherapy has leaned heavily on disease framing. A medical solution requires a medical problem, and a chronic medical problem provides a rationale for long-term medical treatment.

Designating something as a disease is compelling, precisely because the term itself implies a concrete and coherent pathology. But medicine has never reached consensus on what the term “disease” precisely refers to. As such, disease framing is almost always controversial, particularly for prevalent public health problems like obesity.

Epidemiological evidence shows that obesity, particularly at higher BMI thresholds, is associated with substantially elevated risks of cardiovascular disease, type 2 diabetes, stroke, and premature mortality. Basic and translational research has identified numerous biological mechanisms — genetic susceptibility, appetite-regulation pathways, neuroendocrine processes, metabolic adaptation — that contribute to weight gain and impede its loss.

But neither epidemiological harm nor biological mechanism, on their own, settle the question of disease status. Many that have identifiable biological correlates and are associated with substantial morbidity and mortality — including loneliness, aging, and chronic stress — are not typically understood as diseases. But not all diseases are defined primarily by their mortality burden — consider endometriosis or psoriasis, for example.

As such, determining whether a condition constitutes a disease often requires a further judgement about what kinds of human states and experiences medicine ought to classify as pathological. This is why disease classification is never a purely scientific exercise. It is as much an institutional, political, and social process that determines which conditions attract research funding, clinical attention, insurance coverage, and public concern.

Because obesity emerges from a complex interaction of biological, psychological, social, economic, and environmental factors — ranging from genetics and metabolism to food affordability, urban design, stress, and social deprivation — it has long occupied an uneasy and contested position within medical diagnosis.

The American Medical Association’s (AMA) own deliberations on whether obesity should be considered a disease illustrate this clearly. In its 2013 report, the AMA Council on Science and Public Health noted that there was no single, clear, authoritative definition of disease, that BMI remained an imperfect clinical measure, and that it was unclear whether recognizing obesity as a disease rather than a condition, disorder, or risk factor would improve health outcomes. The council also explicitly considered the institutional consequences of disease designation: reimbursement, drug approval, prescribing behavior, insurer coverage, stigma, and the possible shift from public-health interventions toward pharmacological and surgical treatment. The council concluded that there was insufficient evidence to support classifying obesity as a disease.

The full membership voted otherwise. The final overriding decision was therefore not simply a process of adjudicating biological facts, but a judgment about what classification might do.

That distinction between the biological and political dimensions of “disease” is important because, as the AMA council noted, disease classifications do things. By naming a condition as a disease, institutions transform it from a collection of observations into a new class of object, creating new possibilities for intervention, regulation, and investment. New resources become available, new forms of expertise emerge, and new — often legal — obligations are imposed on governments, clinicians, researchers, insurers, and patients. They also do something else: They reorganize the ways in which we conceive of ourselves and our bodies.

The more pressing question is not whether obesity should be a disease, but who are the beneficiaries of its disease status — and whether the answer has changed now that GLP-1 drugs such as Wegovy and Mounjaro have become some of the most commercially successful medicines in history. When diagnostic classifications collide with commercial incentives, it’s easy to lose sight of the distinction between identifying disease and the creation of new markets.

It’s worth noting first that GLP-1 drugs can be unequivocally helpful. Semaglutide and related GLP-1 therapies produce clinically meaningful weight loss and have demonstrated cardiovascular benefits that will improve and extend many lives.

Yet there is no free lunch in pharmacotherapy, and a wholesale embrace of the disease framing of obesity without examining the broader consequences risks narrowing our understanding of both the problem and its solutions.

Four things in particular are at risk.

The first is clinical. Disease framing directs resources and attention toward pharmacological intervention and away from behavioral, psychological, and environmental approaches, not because those approaches are ineffective, but because they are less patentable. Obesity is clearly multifactorial, and emphasizing biology spotlights biological solutions, which biases our selection of choices related to our health. Last month, France’s medicines regulator fined Novo Nordisk approximately $2 million and Eli Lilly $127,000 over direct-to-consumer obesity awareness campaigns. In Lilly’s case, regulators argued that their campaign titled “Obesity is a Sick Thing” implied that pharmacological treatment was the primary solution to obesity by excluding reference to alternative approaches to weight management.

The second is political. When the problem is located in individual biology, the solution is too — and the food industry, city planners, and policymakers exit the frame, along with any serious reckoning with the environments that make obesity so prevalent in the first place.

The third concerns risk. Evidence indicates that many patients who discontinue GLP-1 drugs regain much of the lost weight, creating strong incentives for long-term if not indefinite treatment. Counterfeit markets are already emerging, which can have serious adverse effects for consumers. The drugs are also being diverted for purely aesthetic use, accelerating abuse within problematic diet cultures. And although GLP-1 drugs have an overall favorable benefit-risk profile when appropriately prescribed, they are not benign: Gastrointestinal effects are common, discontinuation is frequent in real-world settings, and regulators continue to monitor rarer concerns including gallbladder disease, pancreatitis, aspiration risk, and psychiatric symptoms.

The fourth, and maybe the most elusive, concerns self-conception. To be told that obesity is a chronic disease that may require potentially pharmaceutical management is to be handed a very particular account of yourself. For some, this may be liberating, replacing moral blame with medical recognition; for others, it may exchange one form of stigma for another — disease framing has always had an ambivalent relationship with stigma. The obese person once judged for lacking willpower may instead be judged for failing to comply with treatment, failing to lose enough weight, or failing to remain on medication. Disease framing may reduce blame, but it can also recast body size as a lifelong pathology requiring surveillance and management.

There are instructive parallels with the arrival of SSRIs in the 1990s. As antidepressants became central to psychiatric practice, depression was progressively reframed — in clinical guidelines, pharmaceutical advertising, and popular culture — as a disorder of neurochemistry best addressed through medication. That framing entrenched a model of distress that underemphasized psychological, social, and economic contributors, directed resources toward pharmacological solutions, and shaped a generation of patients who understood their suffering through the language of chemical imbalance — an explanation whose scientific foundations have since been seriously questioned.

Today, despite the continued widespread use of antidepressants, medicine is grappling with questions of efficacy, long-term use, withdrawal syndromes, and a growing de-prescribing movement. In the meantime, depression remains one of the leading causes of disability worldwide.

I’m not arguing that framing depression as a disease was the wrong decision, nor that obesity is not a disease. But I do think an important element is getting overlooked: In both cases, the designation as a disease aligns uncomfortably close with commercial incentives, crowding out discussion of the condition’s social, psychological, and economic dimensions.

Max Moser is a research fellow in psychology at University College London and a freelance writer. He completed his Ph.D. at UCL, where he researched psychotherapeutic treatments for depression. His writing focuses on the conceptual and ethical questions raised by developments in medicine, mental health, and technology.