Obesity carries the largest avoidable health burden of the century, finds new Lancet Commission
A major new Lancet Commission compared 17 threats to global health, including climate change, pandemics, nuclear conflict and malicious use of artificial intelligence. It found that obesity accounts for the largest potentially avoidable health burden between now and 2100. For the World Obesity Federation, the findings support a case the obesity community has been making for decades, and show why action cannot wait.
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Obesity is the leading threat in 154 of 204 countries and territories, and in the top four in every one
The Lancet Commission on 21st century global threats to health was published in The Lancet on 11 October 2026 and formally launched at the World Health Summit in Berlin. It aims to identify and compare the biggest threats to human health over the rest of the century. The Commission is led by Professor Christopher Murray and Dr Natalia Kanem with a large international group of commissioners. It is one of the most ambitious attempts yet to measure very different threats on a single scale.
What the Commission set out to do
The Commission argues that recent shocks show how quickly assumptions about stability can be overturned. These include COVID-19, major geopolitical conflict, accelerating climate impacts, sharp cuts to development assistance for health and the arrival of powerful AI systems. It calls on governments and multilateral institutions to replace short-term thinking with regular, systematic risk assessment and preparedness planning.
To compare threats fairly, the Commission measures each one by its amenable burden. This is the gap in disability-adjusted life years (DALYs) between a plausible best and a plausible worst future from 2025 to 2100. Put simply, it asks how much death and disability policy action could realistically prevent. The plausible scenarios are based on what countries have actually achieved since 1990, not on hypothetical ideals.
The Commission identified:
- Two with the potential to cause human extinction: nuclear conflict with nuclear famine, and the malicious use of AI, including AI-enabled bioweapons.
- Fifteen "major catastrophic" threats: air pollution, antimicrobial resistance, childhood malnutrition, climate change, collapse of development assistance for health, conventional conflict, high alcohol use, high blood pressure, income inequality, low educational attainment, naturally occurring pandemics, obesity, poor mental health, smoking and unhealthy ageing.
Obesity: the largest avoidable burden
The Commission defines obesity broadly as the combined cluster of high body mass index (BMI), poor diet and low physical activity, a measure that is most widely applicable for all countries. In 2023, these factors already accounted for more than a tenth (10.4%) of all health loss worldwide. They are linked to 54 health outcomes, including cardiovascular disease, type 2 diabetes, chronic kidney disease and several cancers.
The findings are striking:
Obesity carries the largest avoidable burden of any threat
23.1 billion DALYs could be avoided between 2025 and 2100 by moving from the plausible worst to the plausible best obesity scenario. This is the largest of all 17 threats and equals 9.4% of all forecast health loss this century. By comparison, the COVID-19 pandemic caused around 500 million DALYs.
Obesity is the leading threat in 154 of 204 countries and territories
It ranks in the top four in every single one of them. No other threat comes close to this consistency.
It is the leading threat in every world region except sub-Saharan Africa
Even there, the obesity-related avoidable burden is the largest of any region in absolute terms, at 6.4 billion DALYs.
Prevalence will keep rising if current trends continue
The Commission's reference scenario forecasts that 60% of adults and nearly one in three children and adolescents will be living with overweight or obesity by 2050.
The burden is expected to shift increasingly towards low- and middle-income countries
Metabolic complications arise at lower BMI levels in these countries. The Commission is frank about past efforts, stating that policies to reduce BMI “have failed to date”. It identifies the food and beverage industry’s considerable influence over regulation as a real barrier to progress.
A chronic disease, not a personal failing
The Commission groups obesity with diet and physical activity for modelling purposes. Its own evidence shows that rising obesity cannot be explained by individual behaviour or income alone. It points to changes in the food supply, the rise of ultra-processed foods, the removal of physical activity from schools and declining sleep, all of which are shaped by the environments people live in.
This supports a central principle of the World Obesity Federation’s work: obesity is a chronic disease and must be treated as one.
Dr Bruno Halpern, President of the World Obesity Federation, said:
“Obesity must be recognised and addressed as a chronic disease, not simply as a matter of individual choices or personal responsibility.”
“For decades, those of us dedicated to obesity care and research have argued that obesity is one of the greatest public health challenges of the 21st century. Seeing obesity recognised so prominently in a major global health assessment is an important milestone.”
Prevention and treatment: both essential
The Commission's best-case scenario includes the newest obesity medicines, assuming that half of people living with overweight or obesity receive treatment, with an average weight reduction of 20%. The Commission notes that this changes the overall picture less than might be expected. Large differences already exist between countries at the same level of development, which shows how much environments and policy matter. It also warns that access to these medicines is likely to follow existing socioeconomic gaps, which could widen health inequalities unless access is actively managed.
For the World Obesity Federation, this confirms that no single response will be enough.
"Prevention and treatment are not the same thing. Both are essential, but they require different strategies, policies and investments," said Dr Halpern. "Healthier environments and prevention cannot replace the need for evidence-based, long-term care for the millions of people already living with the disease."
From evidence to action
The Commission ends with three recommendations for moving from reactive to anticipatory action:
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Build and fund threat-ready health systems with dedicated capacity for foresight, prevention, preparedness and protection, including healthier food environments.
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Dramatically increase investment in innovation where current tools fall short. Examples include cheaper, more widely manufactured oral obesity medications with fewer side effects.
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Create a recurring Monitor of 21st Century Global Threats to Health to keep threat assessments up to date and in front of political leaders.
The Commission also highlights resilient food systems, equitable universal health coverage and global collective action as enablers that cut across many threats. It names obesity among the challenges that no country can solve alone.
Johanna Ralston, CEO of the World Obesity Federation, said:
The community working in global obesity, including World Obesity Federation members and the World Health Organization, has long recognised that much can be done if silos are dissolved and integrated approaches are supported across public health and health systems. There is much to unpack, but this is an important day for our global efforts."
She also stressed that people with lived experience need to be part of the conversation: "If lived experience were better represented, the understanding of how common and far-reaching obesity is would be much clearer – and so would the practical challenges our systems face in addressing the gaps identified in the Lancet Commission."
What comes next
The World Obesity Federation has worked for many years to bring both prevention and treatment into global health discussions. Our advocacy focuses on greater recognition, reduced stigma, equitable access to care and meaningful policy action. Reports like this one strengthen that case and help ensure obesity finally receives the attention it deserves.
As Dr Halpern put it, the decisions made today could shape global health for generations to come, and the cost of inaction is too high.
Read the full Lancet Commission
The Lancet Commission on 21st century global threats to health is available free with registration.
Read the full commission