Harnessing interdisciplinary research to understand how healthy and unhealthy diets impact the environment

Who Professor David Raubenheimer, Professor Manfred Lenzen, Dr Arunima Malik, Dr Mengyu Li and Navoda Liyana Pathirana; University of Sydney

What What we eat affects both individual and environmental health. Researchers from fields spanning economics, engineering and nutrition have developed advanced data modelling techniques to trace billions of supply chains, linking food producers and consumers. Their work highlights the drivers of dietary choice and is informing policy for the United Nations and other international bodies.

Winners of the 2022 Eureka Prize for Excellence in Interdisciplinary Scientific Research

You’ve combined expertise from fields spanning economics, engineering, computing, nutrition and entomology. How did your research collaboration begin?

The University of Sydney established the Sydney Food and Nutrition Network, an inter-disciplinary network of researchers with an interest in food and nutrition. Through interaction within the network, David, Manfred and Arunima recognised that there was substantial overlap in our interests, with complementary skills that could allow us to make unique contributions to the field. As a first step, our teams were awarded two Australian Research Council Discovery Project grants, which enabled Mengyu to join the team as a postdoctoral research fellow. Navoda was then recruited as a PhD student, funded by a prestigious Faculty of Science Dean’s International Postgraduate Research Scholarship.

Can you tell us a little about the role that each of you play in the team’s research?

Navoda is responsible for integrating large nutritional and dietary data sets with the global economic-environmental supply-chain models. Mengyu runs these models and produces the research output, which she and Navoda then jointly visualise. Arunima uses her experience with global governance networks to distill meaning, interpretation and significance of the results. The economics and computing team is led by Manfred, David leads the nutrition team and both are responsible for the foundational methodological and conceptual developments. David and Manfred are also Navoda’s PhD supervisors.

What have you uncovered about how food consumption habits drive up carbon emissions?

We have made two important discoveries.

First, it is well known that diets rich in animal products are associated with high carbon emissions, and it is therefore important to replace animal foods in the diet with alternatives. Our work showed, however, that the environmental benefits depend on which foods replace animal foods. If the replacements are unprocessed or minimally processed plant foods, such as beans, vegetables and whole grains, carbon emissions are reduced significantly. But if the replacements are highly processed foods, such as mass-produced pizzas, biscuits and ready-made meals, carbon emissions are not reduced — or can even increase. This is because such foods are less satiating than real foods rich in protein (many animal and plant foods) and fibre (plant foods), and their excessive consumption increases carbon emissions. Since overconsumption also drives obesity and associated diseases, highly processed foods are an important target for policy that will benefit both the environment and public health.

Our second important discovery is that carbon emissions associated with the transport of food are much higher than previously estimated — approximately 2-5 times higher. We established this using powerful methods that measure not only the transport of food itself, but also the transport of all equipment, fuels, fertilisers and other materials associated with food production and consumption. There are many reasons why it’s important to take this approach. The environmentally conscious consumer might, for example, select locally produced foods without realising that products used in its production are transported over long distances, and are therefore responsible for high carbon emissions.

What have been some of the most challenging aspects of your research?

Manfred: Our data often look like a confused mess! So much time goes into aligning them, especially given they come from such different sources, as reflected by the fields of expertise among our interdisciplinary team.

David: Nutrition is itself a very complex subject, involving many nutrients combined in countless combinations, throughout numerous foods — which are in turn merged into a diverse range of diets. Combining this with the immense and complex data sources that Manfred, Arunima and Mengyu study is extremely challenging. Working with Navoda, we have developed a new systems framework for combining these complex data and linking diet to environmental and societal issues. However the most challenging — and important — part of our work is yet to come: translating this valuable information into policy and behaviour changes that ensure a sustainable future.

Arunima: Interdisciplinary research requires integration of more than two disciplines, and bridging definitions, theories, data sets, methodologies and concepts across these disciplines. This requires significant dedication and can only be achieved in a highly committed team environment.

What are some of the impacts you hope to see from your team’s work in the future?

Manfred: That we can finally see the light and stop abusing our natural environment.

David: Exactly as Manfred says, but to that I would add “and health”. Our work enables us to identify foods and diets that will benefit the environment, health and important societal issues, such as nutrition equity and the economy. This information can help consumers make sensible dietary choices, but the responsibility cannot be borne by consumers alone. At least equal responsibility falls on government and industry to help create an environment that enables sensible dietary choices. My hope is that as a society, we will act on the information that’s now available, creating and supporting policies that will benefit generations well into the future

What excites you about interdisciplinary scientific research?

Manfred: One never stops learning, but in interdisciplinary research especially, learning seems to accelerate!

David: Different research fields have unique sets of concepts, knowledge and skills. Working across them enables teams to combine each in a new way and discover things that would not otherwise be possible. It also provides opportunities to meet and work with wonderful people. I couldn’t recommend it more highly!

Navoda: Interdisciplinary research offers the chance to think outside the box, not limited by the field of knowledge and expertise. You get to study diverse fields and explore how they can all come together to tackle big problems in the world.

Mengyu: Our interdisciplinary research brings us into contact with researchers working in diverse fields ranging from environmental science, economics and nutrition, to health and engineering. Two heads are better than one, as they say ­­— mixing different ways of thinking can greatly inspire new approaches to solving problems in fields that weren't thought of before.

What does winning a Eureka Prize mean to you?

Manfred: I am grateful for the award because it provides publicity for a good cause: to highlight, and ultimately abate, the worsening exploitation and destruction of our natural environment. It pleases me no end to see talented younger colleagues succeed.

David: I am delighted that our Eureka Prize has highlighted work that I believe has huge potential to benefit both environment and society. It’s especially pleasing the award is in the interdisciplinary category, an approach to research that is essential for solving the world’s most “wicked” problems. Like Manfred, I am particularly happy to see the talent and commitment of our young colleagues rewarded. The future is in their hands!

The Australian Museum Eureka Prizes are the country’s most comprehensive national science awards, honouring excellence across the areas of research & innovation, leadership, science engagement, and school science.