Executive summary

The Global Syndemic of Obesity, Undernutrition, and Climate Change: The Lancet Commission report

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Boyd A Swinburn, Vivica I Kraak, Steven Allender, Vincent J Atkins, Phillip I Baker, Jessica R Bogard, Hannah Brinsden, Alejandro Calvillo, Olivier De Schutter, Raji Devarajan, Majid Ezzati, Sharon Friel, Shifalika Goenka, Ross A Hammond, Gerard Hastings, Corinna Hawkes, Mario Herrero, Peter S Hovmand, Mark Howden, Lindsay M Jaacks, Ariadne B Kapetanaki, Matt Kasman, Harriet V Kuhnlein, Shiriki K Kumanyika, Bagher Larijani, Tim Lobstein, Michael W Long, Victor K R Matsudo, Susanna D H Mills, Gareth Morgan, Alexandra Morshed, Patricia M Nece, An Pan, David W Patterson, Gary Sacks, Meera Shekar, Geoff L Simmons, Warren Smit, Ali Tootee, Stefanie Vandevijvere, Wilma E Waterlander, Luke Wolfenden, William H Dietz

Published Online
January 27, 2019

See Online/Comment http://dx.doi.org/10.1016/S0140-6736(18)33192-1, http://dx.doi.org/10.1016/S0140-6736(18)33243-4, and http://dx.doi.org/10.1016/S0140-6736(18)33249-5

School of Population Health, University of Auckland, Auckland, New Zealand (Prof B A Swinburn MD, S Vandevijvere PhD); Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA, USA (V I Kraak PhD); Global Obesity Centre, School of Health & Social Development, Deakin University, Geelong, VIC, Australia (Prof B A Swinburn; Prof S Allender PhD); Caribbean Community Secretariat, Bridgetown, Barbados (V J Atkins); Institute for Physical Activity and Nutrition (P I Baker PhD) and Global Obesity Centre, School of Health and Social Development (G Sacks PhD), Deakin University, Melbourne, VIC, Australia; Commonwealth Scientific and Industrial Research Organisation, Brisbane, QLD, Australia (J R Bogard PhD, M Herrero PhD); World Obesity Federation, London, UK (H Brinsden, T Lobstein PhD); El Poder del Consumidor, Mexico City, Mexico (A Calvillo); Institute for Interdisciplinary Research in Legal Sciences, Catholic University of Louvain, Louvain-la-Neuve, Belgium (Prof O De Schutter PhD); Public Health Foundation of India, Centre for Chronic Disease Control, New Delhi, India (R Devarajan, S Goenka PhD); Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK (Prof M Ezzati FMedSci); School of Regulation and Global Governance (Prof S Friel PhD) and Climate Change Institute (Prof M Howden PhD), Australian National University, Canberra, ACT, Australia; Center on Social Dynamics & Policy, The Brookings Institution, Washington, DC, USA (R A Hammond PhD, M Kasman PhD); Public Health & Social Policy Department (R A Hammond), Social System Design Lab (Prof P S Hovmand PhD), and Prevention Research Center (A Morshed), Brown School, Washington University in St Louis, St Louis, MO, USA; Institute for Social Marketing, University of Stirling, Stirling, UK (Prof G Hastings PhD); Centre for Food Policy, City University, University of London, London, UK (Prof C Hawkes PhD); Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, USA (L M Jaacks PhD); Department of Marketing and Enterprise, Hertfordshire Business School, University of Hertfordshire, Hatfield, UK (A B Kapetanaki PhD); Centre for Indigenous Peoples’ Nutrition and Environment, McGill University, Montreal, QC, Canada (Prof H V Kuhnlein PhD); Dornsife School of Public Health, Drexel University, Philadelphia, PA, USA (Prof S K Kumanyika PhD); Endocrinology and Metabolism Research Institute, Tehran University of Medical Sciences, Tehran, Iran (Prof B Larijani MD, A Tootee PhD); Milken Institute School of Public Health, The George Washington University, Washington, DC, USA (M W Long PhD, Prof W H Dietz MD); Physical Fitness Research Laboratory of São Caetano do Sul, São Caetano do Sul, São Paulo, Brazil (V K R Matsudo MD); Institute of Health & Society, Newcastle University, Newcastle upon Tyne, UK (S D H Mills PhD); The Morgan Foundation, Wellington, New Zealand (G Morgan PhD, G L Simmons); Obesity Action Coalition, Tampa, FL, USA (P M Nece JD); School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China (Prof A Pan PhD); International Development Law Organization, The Hague, Netherlands (D W Patterson); Health, Nutrition, and Population Global Practice, The World Bank, Washington, DC, USA (M Shekar PhD); African Centre for Cities, University of Cape Town, Cape Town, South Africa (W Smit PhD); Scientific Institute of Public Health (Sciensano), Brussels, Belgium (S Vandevijvere); Department of Public Health Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands (W E Waterlander PhD); and School of Medicine and Public Health, The University of Newcastle, Newcastle, NSW, Australia (L Wolfenden PhD)

Correspondence to: Boyd Swinburn, Private Bag 92019, Auckland 1142, New Zealand


For the Lancet Commission on Obesity see https://www.worldobesity.org/what-we-do/projects/lancet-commission-on-obesity

For the EAT Forum see https://eatforum.org/

Executive summary

Malnutrition in all its forms, including obesity, undernutrition, and other dietary risks, is the leading cause of poor health globally. In the near future, the health effects of climate change will considerably compound these health challenges. Climate change can be considered a pandemic because of its sweeping effects on the health of humans and the natural systems we depend on (ie, planetary health). These three pandemics — obesity, undernutrition, and climate change — represent The Global Syndemic that affects most people in every country and region worldwide. They constitute a syndemic, or synergy of epidemics, because they co-occur in time and place, interact with each other to produce complex sequelae, and share common underlying societal drivers. This Commission recommends comprehensive actions to address obesity within the context of The Global Syndemic, which represents the paramount health challenge for humans, the environment, and our planet in the 21st century.

The Global Syndemic

Although the Commission’s mandate was to address obesity, a deliberative process led to reframing of the problem and expansion of the mandate to offer recommendations to collectively address the triple-burden challenges of The Global Syndemic. We reframed the problem of obesity as having four parts. First, the prevalence of obesity is increasing in every region of the world. No country has successfully reversed its epidemic because the systemic and institutional drivers of obesity remain largely unabated. Second, many evidence-based policy recommendations to halt and reverse obesity rates have been endorsed by Member States at successive World Health Assembly meetings over nearly three decades, but have not yet been translated into meaningful and measurable change. Such patchy progress is due to what the Commission calls policy inertia, a collective term for the combined effects of inadequate political leadership and governance to enact policies to respond to The Global Syndemic, strong opposition to those policies by powerful commercial interests, and a lack of demand for policy action by the public. Third, similar to the 2015 Paris Agreement on Climate Change, the enormous health and economic burdens caused by obesity are not seen as urgent enough to generate the public demand or political will to implement the recommendations of expert bodies for effective action. Finally, obesity has historically been considered in isolation from other major global challenges. Linking obesity with undernutrition and climate change into a single Global Syndemic framework focuses attention on the scale and urgency of addressing these combined challenges and emphasises the need for common solutions.

Syndemic drivers

The Commission applied a systems perspective to understand and address the underlying drivers of The Global Syndemic within the context of achieving the broad global outcomes of human health and wellbeing, ecological health and wellbeing, social equity, and economic prosperity. The major systems driving The Global Syndemic are food and agriculture, transportation, urban design, and land use. An analysis of the dynamics of these systems sheds light on the answers to some fundamental questions. Why do these systems operate the way they do? Why do they need to change? Why are they so hard to change? What leverage points (or levers) are required to overcome policy inertia and address The Global Syndemic? The Commission identified five sets of feedback loops as the dominant dynamics underlying the answers to these questions. They include: (1) governance feedback loops that determine how political power translates into the policies and economic incentives and disincentives for companies to operate within; (2) business feedback loops that determine the dynamics for creating profitable goods and services, including the externalities associated with damage to human health, the environment, and the planet; (3) supply and demand feedback loops showing the relationships that determine current consumption practices; (4) ecological feedback loops that show the unsustainable environmental damage that the food and transportation systems impose on natural ecosystems; and (5) human health feedback loops that show the positive and negative effects that these systems have on human health. These interactions need to be elucidated and methods for reorienting these feedback systems prioritised to mitigate The Global Syndemic.

Key messages

The pandemics of obesity, undernutrition, and climate change represent three of the gravest threats to human health and survival. These pandemics constitute The Global Syndemic, consistent with their clustering in time and place, interactions at biological, psychological, or social levels, and common, large-scale societal drivers and determinants. Their interactions and the forces that sustain them emphasise the potential for major beneficial effects on planetary health that double-duty or triple-duty actions, which simultaneously act on two or all three of these pandemics, will have. To mitigate The Global Syndemic, the Commission proposed the following nine broad recommendations, under which sit more than 20 actions:

  • Think in Global Syndemic terms to create a focus on common systemic drivers that need common actions.
  • Join up the silos of thinking and action to create platforms to work collaboratively on common systemic drivers and double-duty or triple-duty actions.
  • Strengthen national and international governance levers to fully implement policy actions which have been agreed upon through international guidelines, resolutions and treaties.
  • Strengthen municipal governance levers to mobilise action at the local level and create pressure for national action
  • Strengthen civil society engagement to encourage systemic change and pressure for policy action at all levels of government to address The Global Syndemic
  • Reduce the influence of large commercial interests in the public policy development process to enable governments to implement policies in the public interest to benefit the health of current and future generations, the environment, and the planet
  • Strengthen accountability systems for policy actions to address The Global Syndemic
  • Create sustainable and health-promoting business models for the 21st century to shift business outcomes from a short-term profit-only focus to sustainable, profitable models that explicitly include benefits to society and the environment
  • Focus research on The Global Syndemic determinants and actions to create an evidence base of systemic drivers and actions, including indigenous and traditional approaches to health and wellbeing

Double-duty or triple-duty actions

The common drivers of obesity, undernutrition, and climate change indicate that many systems-level interventions could serve as double-duty or triple-duty actions to change the trajectory of all three pandemics simultaneously. Although these actions could produce win-win, or even win-win-win, results, they are difficult to achieve. A seemingly simple example shows how challenging these actions can be. National dietary guidelines serve as a basis for the development of food and nutrition policies and public education to reduce obesity and undernutrition and could be extended to include sustainability by moving populations towards consuming largely plant-based diets. However, many countries’ efforts to include environmental sustainability principles within their dietary guidelines failed due to pressure from strong food industry lobbies, especially the beef, dairy, sugar, and ultra-processed food and beverage industry sectors. Only a few countries (ie, Sweden, Germany, Qatar, and Brazil) have developed dietary guidelines that promote environmentally sustainable diets and eating patterns that ensure food security, improve diet quality, human health and wellbeing, social equity, and respond to climate change challenges.

The engagement of people, communities, and diverse groups is crucial for achieving these changes. Personal behaviours are heavily influenced by environments that are obesogenic, food insecure, and promote greenhouse-gas emissions. However, people can act as agents of change in their roles as elected officials, employers, parents, customers, and citizens and influence the societal norms and institutional policies of worksites, schools, food retailers, and communities to address The Global Syndemic. Across systems and institutions, people are decision makers who can vote for, advocate for, and communicate their preferences with other decision-makers about the policies and actions needed to address The Global Syndemic. Within the natural ecosystems, people travel, recreate, build, and work in ways that can preserve or restore the environment. Collective actions can generate the momentum for change. The Commission believes that the collective influence of individuals, civil society organisations, and the public can stimulate the reorientation of human systems to promote health, equity, economic prosperity, and sustainability.

Changing trends in obesity, undernutrition, and climate change

Historically, the most widespread form of malnutrition has been undernutrition, including wasting, stunting, and micronutrient deficiencies. The Global Hunger Index (1992–2017) showed substantial declines in under-5 child mortality in all regions of the world but less substantial declines in the prevalence of wasting and stunting among children. However, the rates of decline in undernutrition for children and adults are still too slow to meet the Sustainable Development Goal (SDG) targets by 2030.

In the past 40 years, the obesity pandemic has shifted the patterns of malnutrition. Starting in the early 1980s, rapid increases in the prevalence of overweight and obesity began in high-income countries. In 2015, obesity was estimated to affect 2 billion people worldwide. Obesity and its determinants are risk factors for three of the four leading causes of non-communicable diseases (NCDs) worldwide, including cardiovascular diseases, type 2 diabetes, and certain cancers.

Extensive research on the developmental origins of health and disease has shown that fetal and infant undernutrition are risk factors for obesity and its adverse consequences throughout the life course. Low-income and middle-income countries (LMICs) carry the greatest burdens of malnutrition. In LMICs, the prevalence of overweight in children less than 5 years of age is rising on the background of an already high prevalence of stunting (28%), wasting (8·8%), and underweight (17·4%). The prevalence of obesity among stunted children is 3% and is higher among children in middle-income countries than in lower-income countries.

The work of the Intergovernmental Panel on Climate Change (IPCC), three previous Lancet Commissions related to climate change and planetary health (2009–15), and the current Lancet Countdown, which is tracking progress on health and climate change from 2017 to 2030, have provided extensive and compelling projections on the major human health effects related to climate change. Chief among them are increasing food insecurity and undernutrition among vulnerable populations in many LMICs due to crop failures, reduced food production, extreme weather events that produce droughts and flooding, increased food-borne and other infectious diseases, and civil unrest. Severe food insecurity and hunger are associated with lower obesity prevalence, but mild to moderate food insecurity is paradoxically associated with higher obesity prevalence among vulnerable populations.

Wealthy countries already have higher burdens of obesity and larger carbon footprints compared with LMICs. Countries transitioning from lower to higher incomes experience rapid urbanisation and shifts towards motorised transportation with consequent lower physical activity, higher prevalence of obesity, and higher greenhouse-gas emissions. Changes in the dietary patterns of populations include increasing consumption of ultra-processed food and beverage products and beef and dairy products, whose production is associated with high greenhouse-gas emissions. Agricultural production is a leading source of greenhouse-gas emissions.

The economic burden of The Global Syndemic

The economic burden of The Global Syndemic is substantial and will have the greatest effect on the poorest of the 8·5 billion people who will inhabit the earth by 2030. The current costs of obesity are estimated at about $2 trillion annually from direct health-care costs and lost economic productivity. These costs represent 2·8% of the world’s gross domestic product (GDP) and are roughly the equivalent of the costs of smoking or armed violence and war.

Economic losses attributable to undernutrition are equivalent to 11% of the GDP in Africa and Asia, or approximately $3·5 trillion annually. The World Bank estimates that an investment of $70 billion over 10 years is needed to achieve SDG targets related to undernutrition, and that achieving them would create an estimated $850 billion in economic return. The economic effects of climate change include, among others, the costs of environmental disasters (eg, drought and wildfires), changes in habitat (eg, biosecurity and sea-level rises), health effects (eg, hunger and diarrhoeal infections), industry stress in sectors such as agriculture and fisheries, and the costs of reducing greenhouse-gas emissions. Continued inaction towards the global mitigation of climate change is predicted to cost 5–10% of global GDP, whereas just 1% of the world’s GDP could arrest the increase in climate change.

Actions to address The Global Syndemic

Many authoritative policy documents have proposed specific, evidence-informed policies to address each of the components of The Global Syndemic. Therefore, the Commission decided to focus on the common, enabling actions that would support the implementation of these policies across The Global Syndemic. A set of principles guided the Commission’s recommendations to enable the implementation of existing recommended policies: be systemic in nature, address the underlying causes of The Global Syndemic and its policy inertia, forge synergies to promote health and equity, and create benefits through double-duty or triple-duty actions.

The Commission identified multiple levers to strengthen governance at the global, regional, national, and local levels. The Commission proposed the use of international human rights law and to apply the concept of a right to wellbeing, which encompasses the rights of children and the rights of all people to health, adequate food, culture, and healthy environments. Global intergovernmental organisations, such as the World Trade Organization, the World Economic Forum, the World Bank, and large philanthropic foundations and regional platforms, such as the European Union, Association of Southeastern Nations, and the Pacific Forum, should play much stronger roles to support national policies that address The Global Syndemic. Many states and municipalities are leading efforts to reduce greenhouse-gas emissions by incentivising less motorised travel and improving urban food systems. Civil society organisations can create a greater demand for national policy actions with increases in capacity and funding. Therefore, in addition to the World Bank’s call for $70 billion for undernutrition and the Green Climate Fund of $100 billion for LMICs to address climate change, the Commission calls for $1 billion to support the efforts of civil society organisations to advocate for policy initiatives that mitigate The Global Syndemic.

A principal source of policy inertia related to addressing obesity and climate change is the power of vested interests by commercial actors whose engagement in policy often constitutes a conflict of interest that is at odds with the public good and planetary health. Countering this power to assure unbiased decision making requires strong processes to manage conflicts of interest. On the business side, new sustainable models are needed to shift outcomes from a profit-only model to a socially and environmentally viable profit model that incorporates the health of people and the environment. The fossil fuel and food industries that are responsible for driving The Global Syndemic receive more than $5 trillion in annual subsidies from governments. The Commission recommends that governments redirect these subsidies into more sustainable energy, agricultural, and food system practices. A Framework Convention on Food Systems would provide the global legal structure and direction for countries to act on improving their food systems so that they become engines for better health, environmental sustainability, greater equity, and ongoing prosperity.

Stronger accountability systems are needed to ensure that governments and private-sector actors respond adequately to The Global Syndemic. Upstream monitoring is needed to measure implementation of policies, examine the commercial, political, economic and sociocultural determinants of obesity, evaluate the impact of policies and actions, and establish mechanisms to hold governments and powerful private-sector actors to account for their actions.

Similarly, platforms for stakeholders to interact and secure funding, such as that provided by the EAT Forum for global food system transformation, are needed to allow collaborations of scientists, policy makers, and practitioners to co-create policy-relevant empirical, and modelling studies of The Global Syndemic and the effects of double-duty and triple-duty actions. Bringing indigenous and traditional knowledge to this effort will also be important because this knowledge is often based on principles of environmental stewardship, collective responsibilities, and the interconnectedness of people with their environments.

The challenges facing action on obesity, undernutrition, and climate change are closely aligned with each other. Bringing them together under the umbrella concept of The Global Syndemic creates the potential to strengthen the action and accountabilities for all three challenges. Our health, the health of our children and future generations, and the health of the planet will depend on the implementation of comprehensive and systems-oriented responses to The Global Syndemic.


Obesity has risen inexorably worldwide in the past 4–5 decades and is now one of the largest contributors to poor health in most countries.1 Despite nearly two decades of recommendations from authoritative national and international organisations, especially WHO, the implementation of effective obesity-prevention policies has been slow and inconsistent.2 The Commission recognises that this patchy progress is intrinsic to the complexity of the obesity problem itself, and uses the collective term policy inertia to describe the combined effects of inadequate political leadership and governance to enact policies to respond to The Global Syndemic, strong opposition to those policies by powerful commercial interests, and a lack of demand for policy action by the public.3 Although some high-income countries have experienced a plateau or slight decline in childhood obesity, no country has decreased the obesity epidemic across its population.

The Lancet Commission on Obesity (panel 1) developed a broader approach to obesity, on the basis of the concept that the obesity pandemic is one element of The Global Syndemic, which also includes undernutrition and climate change.

Panel 1: The Lancet Commission on Obesity

The Lancet Commission on Obesity was formed following the publication of two Lancet Series on Obesity in 2011 and 2015. The Commission was under the auspices of The Lancet, the University of Auckland, George Washington University, and the World Obesity Federation. The Commission was comprised of 26 Commissioners and 17 Fellows from 14 countries. The disciplines and expertise of the Commissioners included global obesity, population health, nutrition (including undernutrition), food systems (including indigenous food systems), physical activity, political science and policy making, climate change, urban planning, epidemiology, consumer advocacy, human rights, international law, trade, health equity, social determinants, economics, marketing, agriculture, systems science, community interventions, implementation science, medicine, business, financing, and the experience of living with obesity.

The aims of the Commission were to:

  • Identify the systemic commonalities in drivers and solutions across obesity, undernutrition, and climate change.
  • Describe double-duty or triple-duty policies and actions to address The Global Syndemic, and ways to strengthen accountability systems for their implementation.

The Commission’s work on The Global Syndemic came from two group model building sessions organised for the Commissioners, a review of existing conceptual and computational models, and three face-to-face meetings between February, 2016, and July, 2017. Additionally, consultation workshops were held around the world during 2017, to obtain feedback on the Commission’s concepts. These workshops were hosted by the Australian National University, Canberra; Washington University, St Louis; The World Bank, Washington DC; Centre for Food Policy, City, University of London, UK; International Atomic Energy Agency, WHO, and UNICEF, Vienna, Austria; Endocrinology and Metabolism Research Institute of Tehran, University of Medical Sciences, Tehran, Iran; a satellite meeting at the International Congress on Obesity, Buenos Aires, Argentina; Huazhong University of Science and Technology, Wuhan, China; and the Center for Chronic Disease Control, Delhi, India.

As originally defined, a syndemic is two or more diseases with three characteristics: they co-occur in time and place, they interact with each other at biological, psychological, or societal levels, and they share common underlying societal drivers.4 Although the syndemic concept was originally used to describe the interaction of two or more diseases at the individual level, it provides a useful construct with which to consider the interaction of two or more pandemics, in this case, obesity, undernutrition, and climate change, with climate change being accorded pandemic status because of its projected effects on human health (panel 2).

Panel 2: Definitions

The Commission used the following definitions in this report:

  • Syndemic is two or more diseases that co-occur, interact with each other and have common societal drivers.4 The Global Syndemic applies this concept to the pandemics of obesity, undernutrition, and climate change.
  • Malnutrition in all its forms refers to an abnormal physiological condition caused by inadequate, unbalanced, or excessive consumption of macronutrients or micronutrients.5 We operationalised malnutrition in burden of disease terms as the combined components of child and maternal malnutrition, high body-mass index (BMI), and dietary risks, representing a composite variable of dietary components associated with NCDs, such as diets low in whole grains, fruit, vegetables, nuts, and seeds and high in sodium, red meat, and sugar-sweetened beverages (Ashfin A, Institute for Health Metrics and Evaluation, Seattle, WA, USA, personal communication).6
  • Undernutrition encompasses stunting (low height-for-age), wasting (low weight-for-height), underweight (low weight-for-age), and micronutrient deficiencies (eg, iron, vitamin A, and iodine). In this report, we use the term to refer to child and maternal undernutrition as part of malnutrition in all its forms.
  • Obesity is defined as a BMI >30 kg/m2, but when we refer to obesity as part of The Global Syndemic, we use the term to encompass high BMI and NCD dietary risks that form part of malnutrition in all its forms.
  • Obesogenic environments are the collective physical, economic, policy, and sociocultural surroundings, opportunities, and conditions that promote obesity.7, 8
  • Policy inertia is the collective term for the combined effects of inadequate political leadership and governance to enact policies to respond to The Global Syndemic, strong opposition to those policies by powerful commercial interests, and a scarcity of demand for policy action by the public.
  • Double-duty or triple-duty actions refer to strategies that address two or three of the components of The Global Syndemic.
  • Best buys refer to WHO’s evidence-informed interventions (eg, sodium reduction) that are feasible and cost-effective for governments to implement and are likely to provide broad benefits to populations in reducing NCD risks.9
  • People-first language emphasises the individual rather than the disease consistent with the terminology used for other diseases. An obese person is an identity, and infers that the person with obesity is responsible for their condition, whereas a person with obesity is a person with a disease.
  • Sustainable food systems promote the global outcomes of human health, ecological health, social equity, and economic prosperity. They have a low environmental impact, support biodiversity, contribute to food and nutrition security, and support local food cultures and traditions.10

Malnutrition in all its forms, which includes obesity, undernutrition, and dietary risks for non-communicable diseases (NCDs), is already the biggest cause by far of health loss globally (Ashfin A, Institute for Health Metrics and Evaluation, Seattle, WA, USA, personal communication). The increasing health effects of climate change in the future means that The Global Syndemic will remain the largest cause of poor health globally and in each country. Furthermore, The Global Syndemic disproportionally affects poorer countries and, in all countries, poorer populations. Poverty amplifies the effects of The Global Syndemic, and the Syndemic exacerbates and perpetuates poverty. Therefore, common actions to address poverty and The Global Syndemic are essential to improve population health and reduce social and health inequities.

The Commission developed a conceptual model for The Global Syndemic that represents an inside-out version of the socioecological model.11 The natural systems upon which everything on the planet depends are at the centre, and the layers of human systems overlay that with the most fundamental systems (eg, governance) on the inside and moving outwards from macro to micro systems. The Foresight Obesity Systems Map,12 which was the first conceptual model to show obesity as a consequence of complex adaptive systems, has a structure centred on the individual, similar to the socioecological model. This structure is helpful in explaining differences between individuals but less helpful in explaining epidemics sweeping across entire populations.

The major governance levers of those in power in The Global Syndemic model were identified as policies, economic incentives or disincentives, and social norms. The Commission calls these deep drivers because they dictate the operating conditions for the major macro systems (ie, food and transportation systems, urban design, and land use) that create The Global Syndemic. The meso systems or settings (eg, schools, retail, workplaces, and communities) and micro systems or social networks (eg, families, friends, and workplace colleagues) are strongly influenced by the layers underneath. The underlying common causes of obesity, undernutrition, and climate change are explained through this conceptual framework.

After describing The Global Syndemic in systems terms, this report turns to potential systemic actions that could address multiple components of The Global Syndemic through double-duty or triple-duty actions. With some modifications, the many current, evidence-based recommendations to address nutrition and physical inactivity could provide a basis for identifying and quantifying double-duty or triple-duty actions. A solution-oriented approach to The Global Syndemic demands use of system-dynamics approaches and tools to identify how actions can create virtuous feedback loops to produce better health and environmental outcomes, and how they can limit the damage and unintended consequences of the existing feedback loops that are creating the problems.

This report describes additional sources of actions to strengthen governance and accountability systems, address vested industry interests, leverage international human rights treaties, and activate community actions and social change. Vested interests constitute a major source of policy inertia that prevents change to the existing systems. For example, national food producers and transnational ultra-processed food and beverage manufacturers often exert a disproportionate influence on legislators and the policy making process. Governments face the challenge of regaining control to protect policy making and prioritise the public good over commercial interests, and restructuring business models to minimise negative externalities that contribute to poor human health and damage environments. We assert that there is a right to wellbeing based on state obligations to ensure that all people, especially vulnerable populations, have access to healthy foods and healthy environments. Many initiatives to address The Global Syndemic can begin at the community level, where the systems under local control can be collectively reoriented to achieve better health and environmental outcomes. Nonetheless, community initiatives will need to be reinforced by a regulatory and policy framework, as well as economic incentives and disincentives, to provide healthy and affordable food and beverage choices and promote social and economic environments that encourage physical activity and healthy behaviours.

The Commission believes that the recognition of The Global Syndemic will foster a convergence of many interests, encourage the emergence of an effective social movement, and realign policy measures and governance to reduce obesity, undernutrition, and climate change. Comprehensive and systemic actions are urgently needed.

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