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

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. 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. 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 messagesThe 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 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 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. 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 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. 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.