South Africa must apply HIV's stigma lessons to obesity crisis

A woman sat in an HIV research clinic in Johannesburg in 2019, tears streaming down her face, asking her doctor a question that would come to define a new health crisis: Why couldn't she stop gaining weight? Her antiretroviral regimen was doing exactly what it was supposed to do—the virus was undetectable, her health restored. But the medicines that saved her life were also reshaping her body in ways she couldn't control. She kept buying larger clothes. Her doctors told her to eat less and move more. Nothing worked.

Her story is not unique. It is, in fact, a window into one of South Africa's most pressing and least discussed health challenges: the collision between two epidemics, and the stigma that surrounds both. As thousands of scientists, activists and policymakers gather in Rio de Janeiro this week for the 26th International Aids Conference, much of the conversation will focus on protecting decades of progress against HIV amid devastating global funding cuts. But the most urgent lesson from that hard-won progress has little to do with the virus itself. It has everything to do with how societies treat people whose bodies don't fit the shape of health.

South Africa has already lived through one epidemic in which shame kept people from seeking treatment. The country watched as stigma—the assumption that weight loss meant HIV, that a diagnosis meant moral failure—delayed testing and deepened a crisis that cost countless lives. Political denial made it worse. But activism eventually prevailed. HIV stopped being treated as a character flaw and came to be recognized as a medical condition deserving of rights, evidence-based care, and access to treatment. That transformation saved millions.

Today, South Africa faces a different form of stigma, but one built on strikingly similar assumptions. Obesity is increasingly framed as a failure of willpower—the result of greed, laziness, eating the wrong foods. Research now shows the reality is far more complex. Obesity, like high blood pressure or diabetes, is a progressive disease shaped by genes, environment, and a food system that has fundamentally changed. Yet society, and much of medicine, has not caught up. People in larger bodies are still imagined as weak or undisciplined. Their illness is treated as deserved rather than worthy of care. Healthcare workers themselves often deliver lectures and jokes instead of compassion.

The overlap between South Africa's HIV and obesity epidemics should alarm anyone working in public health. Newer antiretroviral regimens are linked to greater weight gain than older treatments, with the largest increases seen in women and Black patients. Some of this is the body's natural return to health after HIV is controlled. Some appears to be a direct effect of the drugs themselves. The result is a cruel shift: someone who once feared being seen as too thin now feels judged for being too large, carrying the double burden of a hidden HIV status and highly visible body-size judgment. Meanwhile, obesity among people without HIV has surged, driven by cheap ultra-processed food, poverty, stress, and aging. The two trends are not separate. They share the same structural drivers.

This is where South Africa's HIV history offers a warning. In the early 2000s, influential voices argued that prevention was far more cost-effective than treatment. In practice, that thinking helped normalize the idea that poor people should wait for treatment while prevention efforts were strengthened—that the failures of prevention should be left to die. South Africa knows how destructive that logic became. Access to antiretrovirals expanded not because the argument faded away, but because activists, clinicians, researchers and communities forced treatment access into the center of public life.

Today, the debate around obesity medicines sounds eerily familiar. The arrival of GLP-1 receptor agonists—drugs like semaglutide and tirzepatide that help people feel fuller and eat less—has triggered real excitement and real backlash. Warnings have emerged that obesity is being over-medicalized, that people will abandon healthy habits, that treatment will bankrupt medical aids, that prevention must not be sidelined. In HIV, the country heard the same arguments: that treatment access played into the hands of pharmaceutical companies, that people would abandon condoms, that the country could not afford the medicines, that you could not treat your way out of an epidemic. Two decades on, those commentators were disastrously wrong for millions of people.

The lesson from HIV is not that prevention and treatment are rivals. It is that you need to do both at once. No medication will fix the food markets, make healthy food affordable, make neighborhoods safer, or raise wages. But withholding effective treatment from people who need it now, especially poorer people, causes avoidable harm. For many South Africans living with HIV, the cruelty is particularly sharp: lifesaving antiretrovirals are available through the public health system, but support for one of their most common side effects is not. Patients are left alone with a problem that is medical, social, and deeply personal.

South Africa stands at a fork in the road. On one side is an unregulated market of social-media weight-loss drugs, where desperate and ashamed people take real risks because the health system has given them little else. On the other is a set of effective, well-studied obesity medicines largely reserved for those who can afford them. Doing better would require three things: regulators clamping down on illegal products while giving clear guidance on what works; the health department and medical aids providing access to obesity care within HIV services for those at highest risk; and training for HIV nurses and doctors that treats weight stigma as a clinical harm. Most of all, it would require a government committed to keeping fast-food companies out of schools and fixing a food system that currently leaves people with no real choice but an unhealthy one. HIV activism taught South Africa that stigma kills and treatment saves lives. That lesson is about to be tested again.