The new politics of obesity is being written in milligrams. Within a few short years, drugs like semaglutide and tirzepatide, better known by their brand names Wegovy, Ozempic and Mounjaro, have gone from niche diabetes treatments to cultural phenomena, reshaping everything from celebrity bodies to stock markets. They are now beginning to reshape health policy too.

Governments are scrambling: how far should publicly funded systems go in paying for expensive injections that can deliver 15 to 20% weight loss, but must often be taken indefinitely? Who gets them first: people with diabetes, those with severe obesity and complications, or anyone who can pay privately? And can we justify pouring billions into pharmacological fixes while leaving the food environment and social drivers of obesity largely intact? These questions are no longer abstract. They are already colliding with real-world budget lines, waiting lists and political choices.

The scale of the problem itself is not in dispute. The worldwide prevalence of obesity has more than doubled in the past few decades. Across many high-income countries, a clear majority of adults are now overweight or living with obesity. Once a “rich country” concern, obesity is rising fastest in low- and middle-income settings, tracked closely by type 2 diabetes, cardiovascular disease and some cancers. The economic fallout is enormous: unhealthy diets and nutrition-related non-communicable diseases already cost economies trillions each year through health spending, lost productivity and wider social impacts. In that context, a class of drugs that can reliably reduce weight, improve glycaemic control and lower cardiovascular risk looks, on the surface, like a healthcare and economic gift.

The problem is not whether these drugs work. Clinically, GLP-1 receptor agonists (and the newer dual-agonist tirzepatide) have transformed obesity medicine, delivering far greater weight loss than older pharmacological options and often delaying or avoiding the need for bariatric surgery. Evidence and guidelines are evolving rapidly, and global health agencies are increasingly explicit in recognising obesity as a chronic disease rather than a failure of willpower. The question is how to integrate these drugs into systems already under financial and workforce strain, without deepening inequities or crowding out other priorities.

Take England, for example. NICE recommends semaglutide as an option for adults above certain BMI thresholds who also have at least one weight-related comorbidity, but only within specialist weight management services and usually for a limited treatment period. Tirzepatide also comes with tight eligibility criteria and an emphasis on specialist clinics. On paper this looks measured and sensible: reserve drugs for those at highest clinical risk, prescribe them alongside multidisciplinary support, avoid a free-for-all.

In practice, implementation is uneven and painfully slow. Many eligible patients are being denied access because the specialist clinics required to prescribe these drugs simply do not exist where they live. Some health boards are not accepting referrals at all. For patients already living with diabetes, sleep apnoea and heart disease, the promise of an “NHS-funded injection” becomes yet another mirage in a system that talks about prevention but can barely deliver routine care.

At the same time, the private market is booming. High-street chains and online platforms are selling GLP-1-based injections to anyone who meets looser criteria and can afford hundreds of pounds a month. In some cities, private “weight-loss injections” are now easier to access than an NHS GP appointment. This is not a trivial, cosmetic story. It is a matter of equity. When wealthier, generally healthier people can access powerful new drugs quickly and at scale, while those in more deprived communities wait years for under-resourced clinics, we are baking further health inequalities into a supposedly universal system.

There have also been knock-on effects for people with diabetes. Over the last few years, supply issues have periodically left people struggling to obtain GLP-1 drugs they depend on to manage their blood sugar and avoid organ damage, driven in part by a surge in off-label weight-loss prescribing that outpaced global manufacturing. When a “miracle” obesity drug leaves someone with diabetes unable to access life-sustaining treatment, stewardship is clearly failing.

Proponents of mass rollout insist these drugs will pay for themselves by reducing downstream spending on heart attacks, amputations, joint replacements and intensive care admissions. The logic makes sense. It is also convenient for manufacturers and politicians who prefer simple arithmetic to messy system reform.

If even a fraction of all eligible people in a country like the UK were to start on GLP-1s, annual spend would run into the billions. One plausible scenario has the cost of tirzepatide alone approaching a third of the current primary care medicines budget if uptake is high. At a global level, health systems already account for around a tenth of economic output and employment across OECD countries; adding a long-term, high-cost drug category for tens of millions of people risks crowding out other priorities, from mental health and social care to public health infrastructure.

The politics of pricing is beginning to shift, especially in the US, where headline-grabbing negotiations are driving down listed prices for some high-cost drugs. Even so, GLP-1s will remain a substantial budget line simply because of the volume of potential demand. If wealthy countries struggle with affordability and rational use, the outlook for low- and middle-income countries is bleak. Without substantial price reductions, technology transfer or new financing models, most of the world will watch this revolution from the sidelines.

That is why GLP-1s are fast becoming another chapter in the story of global health inequality. Policy reviews across high-income nations already show wide variation in who gets access, on what terms and with which clinical thresholds, reflecting different underlying beliefs about whether obesity is primarily a biomedical, behavioural or social phenomenon. At the same time, commentators warn that treating these drugs as solutions for rich populations while poorer countries are left with rising obesity and no realistic access risks hard-wiring inequity into global metabolism.

The pattern is familiar. A small number of companies hold patents on blockbuster drugs. Their share prices rise or fall on the back of weight-loss data and speculative trials for other conditions. Manufacturing capacity is allocated first to the most profitable markets. Public health systems in the Global South are left with the old tools: behavioural counselling, patchy lifestyle programmes, and food environments shaped by multinational food and beverage companies that answer to shareholders, not health ministries.

There is a further, subtler danger: that we medicalise away the politics of obesity. None of this is an argument against making GLP-1 drugs available. For many people living with severe obesity and its complications, these treatments can be life-changing, and denying them on moralistic grounds would be unethical. But if we allow the excitement around injections to displace serious work on the structural drivers of ill-health, we will have learned the wrong lesson.

We know, in broad terms, what those drivers are. Food environments saturated with ultra-processed products; urban design that prioritises cars over people; insecure, low-paid work that erodes time and energy for cooking or exercise; marketing budgets that dwarf public health campaigns; widening income gaps that translate directly into gaps in life expectancy. Upstream policies, that regulate marketing, reformulate products, ensure healthy school meals, invest in active travel, and tackle child poverty, consistently show high returns on investment. They are also politically difficult, slow, and rarely the stuff of triumphant press releases.

Approving a new injection is faster. Standing next to a poster of a shrinking waistline is easier than standing up to food lobbies or re-designing entire transport systems. If we are not careful, GLP-1s become a technocratic detour: a way for politicians to look decisive on obesity while avoiding the conflicts and redistributions that real prevention demands.

A more coherent response would start by putting equity at the centre of any public funding decision. That means prioritising people with the highest clinical risk and the highest structural barriers to change rather than simply those who can navigate referral systems or live near flagship clinics. It also means actually building and staffing specialist services in underserved areas, instead of assuming that existing infrastructure can just absorb another complex therapy.

It would link any large-scale investment in GLP-1s to visible progress on upstream measures. If health systems are going to spend billions on these drugs, some of that political and fiscal capital should be coupled with commitments on food reformulation, marketing restrictions, urban planning and poverty reduction. A drug strategy without a food and transport strategy is not serious.

It would also involve much tougher, more transparent price negotiations and, where possible, collective purchasing. If one country can force a dramatic price cut for a high-profile drug, regional blocs can in principle do more. The goal is not to punish innovation, but to stop a single therapeutic class from quietly absorbing budgets that should also fund community prevention, mental health services and social care.

Finally, a coherent strategy would protect diabetes care and plan honestly for the long term. Supplies must be ring-fenced so that people with diabetes are not pushed to the back of the queue by cosmetic demand. And policymakers need to acknowledge that obesity is a chronic, relapsing condition. People often regain weight when GLP-1s are stopped. Short, politically convenient funding windows are not evidence-based, and they are not fair to patients who are told this is a long-term disease.

GLP-1s are forcing health systems to confront uncomfortable truths about what and who they value. We can choose a path where powerful new drugs are integrated thoughtfully into a broader strategy that tackles the food system, inequality and the way we design our cities. Or we can drift into a future where injections keep a fraction of the population slimmer for a while, while the underlying drivers of ill-health go largely untouched.

Obesity is not a failure of individual willpower, and GLP-1s are not a failure of public health. The real failure would be to let this pharmacological revolution distract us from the politics of building healthier societies in the first place.