Global Syndemic?

Why Climate Change, Obesity, and Malnutrition are Not One Problem.
A Global Syndemic?

A major Lancet series authored by 43 researchers announces an alarming and counterintuitive conclusion: global climate change, obesity, and malnutrition are all really one single problem.

This revelation is so counterintuitive, it is largely counterproductive. While connections can be drawn between any major issue, the evidence linking these three problems as one is weak or contradictory. The report distorts the issues and distracts from the kinds of solutions that matter most. In an effort to glue together disconnected ideas, they go so far as to blame obese people as one of the causes of climate change.


The Definition of the Problem

The authors define global malnutrition, obesity, and climate change as a “syndemic,” a word used to refer to diseases and pathologies that interact systematically to create a larger problem that are better tackled together. For example, in some places, the underlying causes of AIDS are so deeply connected to drug addiction that it is difficult to address one problem without also addressing the other.

It is possible, however, to fight obesity without fighting climate change, to fight malnutrition without fighting obesity, etc. So what motivates the authors to believe they are so intertwined?

Not new evidence. Rather, they are motivated by the belief this new classification will help mobilize action. “The enormous health and economic burdens caused by obesity,” they explain, “are not seen as urgent enough to generate the public demand or political will.” As a solution, they believe that: “Linking obesity with undernutrition and climate change into a single Global Syndemic framework focuses attention on the scale and urgency.”

This foundational assumption for the report — that a bigger, singular problem will mobilize change — is itself questionable. Already, it is difficult to motivate individuals to take action for climate change because the problem seems distant and abstract. Adding obesity to climate change to make a bigger, more abstract problem is unlikely to help.


The case for the Global Syndemic

The report claims three central reasons for why climate change, obesity, and malnutrition should be considered a single syndemic. We will consider each in turn.


One: “Obesity, undernutrition, and climate change cluster in time and place.”

Their evidence that these problems are clustered in “time and place” appears to be that they are all occurring at present and on Earth. They do not show that the issues occur together in any particular place, but simply list the negative international consequences of each. By this standard, internet addiction should also qualify.


Two: “Obesity, undernutrition, and climate change interact with each other.”

The authors are right that climate change will likely undermine agricultural production, which may lead to malnutrition. But other connections are more tenuous.

They note that some populations suffer both malnutrition and obesity simultaneously, likely as a result of the low-nutritional content of many processed foods. While this is an alarming trend, malnutrition does not inherently cause obesity, and neither issue causes climate change.

They are right to note that plant-based foods produce less CO2. But not all weight-loss diets emit less CO2: junk food is largely made of plants, and many people eat more meat in an effort to lose weight. It is possible to eat healthy while reducing one’s carbon footprint, but this requires paying attention to two separate problems, not one.

By far the most tenuous connection they draw is between obesity and climate change. They argue that climate change may make fresh food more expensive, so people “might” buy more processed foods and become more obese. Perhaps, but this conjecture about the future does nothing to explain obesity today.


Blaming obese people

Far worse, they also effectively claim that obese people themselves are a cause of climate change. They write that, a “mechanism by which obesity could contribute to climate change is through the increased costs of fossil fuels related to transporting populations with a high prevalence of obesity.” To state this clearly: obese people contribute to climate change because it takes more gas to move them around. The authors further argue that that feeding more obese populations, “will increase the food system’s greenhouse-gas emissions,” presumably because they eat more.

The authors bemoan “the bias and stigmatisation” that people suffering from obesity suffer. Yet they make the far-fetched, derogatory claim that transporting and feeding overweight people is a cause of climate change worth mentioning. The authors acknowledge that these impacts are “very small.” But in their effort to connect these disparate issues, they considered the accusation important enough to note.


Three: “Obesity, undernutrition, and climate change have common systems drivers.”

One way to argue that climate change, obesity, and malnutrition are one problem is by arguing they are caused by the same thing. The authors are startlingly clear on who they blame: “The fossil fuel and food industries ... are responsible for driving The Global Syndemic.” Elsewhere they blame “economic systems” that, “value GDP growth and overlook its role in damaging the health of people, the environment, and the planet.”

Here the authors fall victim to the attribution bias: the tendency to believe bad things happen because someone decided they should happen. Corporate greed certainly plays some part in promoting unhealthy food and denying climate change. But so do political systems, social trends, human psychology, perverse incentives, and myriad other factors.

At least one cause they identify, “car-oriented transportation systems,” contradicts the idea that GDP growth alone is to blame. Building healthy, walkable, transit-oriented communities promotes GDP growth. High-density cities have high economic output, high rates of walking, low carbon impact per person. Walkability is itself associated with economic growth. New York and Hong Kong have a high GDP, in part, because people walk and take transit, not in spite of it.

It is true that people from low-income countries drive and consume less, and therefore produce less CO2. I suspect, however, that the authors’ preferred solution is not to keep people in poverty.


An unnecessary distortion of facts

Adam Smith observed that even a good, caring person would have a stronger emotional reaction to cutting their pinky finger than to learning that, “the great empire of China… were suddenly swallowed up by an earthquake.” People respond to things that feel concrete and personal. Positioning obesity, malnutrition, and climate change as a part of a single global syndemic only makes the issues more abstract and distant.

The three problems certainly influence each other, but so do all major problems: inequality, war, corruption, prejudice, mental ill health, etc. Analyzing how to move forward on any of these things does require understanding how a solution could impact other problems. Conflating multiple problems as one only confuses the clear analysis we need.


  • Tristan Cleveland


Photo by NASA.

Swinburn, Boyd A, Vivica I Kraak, Steven Allender, Vincent J Atkins, Phillip I Baker, Jessica R Bogard, Hannah Brinsden, et al. 2019. “The Global Syndemic of Obesity, Undernutrition, and Climate Change: The Lancet Commission Report.” The Lancet, January. doi:10.1016/S0140-6736(18)32822-8.