Sustainable Nutrition

April 2022

Development of a model investigating future global food system scenarios from a nutrition perspective.

Concerned that human nutritional needs should be at the forefront of sustainable food production decisions, New Zealand scientists at the Riddet Institute in Palmerston North have developed a model enabling researchers and policymakers to investigate future global food system scenarios from a nutrition perspective.


The game-changing DELTA model is being used in New Zealand and internationally to generate informed discussion about food system sustainability. It has been developed through the Riddet Institute’s Sustainable Nutrition Initiative (SNiTM) research programme, and examines the nutritional side of sustainability.


The Institute’s deputy director, Professor Warren McNabb, leads the project with the model development headed by Dr Nick Smith. Professor McNabb says the driver behind the development of DELTA was the Riddet Institute’s concern that environmental and economic factors were starting to override considerations of human nutrition. 


Published in 2021 in the Journal of Nutrition, an internationally recognised, peer-reviewed scientific journal published by the American Society for Nutrition, DELTA starts with the question ‘how does the world feed the world – without exceeding the capacity of the planet?’.


“Before researchers and government policymakers can accurately determine the optimal setting to deliver a sustainable food production system, they need to know under what scenarios is it possible to provide the bioavailable nutrients required,” says Professor McNabb. “They also need to know what scenarios are practical to achieve, for example in terms of the level of change required, the cost of that change and impacts on the affordability of food.”


He adds that the problems to be solved need to be thoroughly understood before embarking on changes that are often difficult and slow to introduce, and extremely challenging to reverse if they turn out to be wrong. “The global food system of the future will be shaped by the shifts in thinking we make today – and a thinking failure today can only lead to a system failure tomorrow.”


Dr Smith says the DELTA model, which covers 175 countries with data obtained from the United Nation’s Food and Agriculture Organization (FAO, see footnote) food balance sheet, allows for a wide range of possible scenarios for feeding the global population to be explored.


“We decided to make it openly accessible on our website so that anyone can have the chance to explore the global food system and see the importance of considering nutrition when thinking about food system sustainability,” he says. As well as being put to use here in New Zealand, it is also being used internationally in research and in teaching. Researchers at the University of Sao Paulo in Brazil and at the University of Lincoln in the United Kingdom are amongst those collaborating with Dr Smith and his colleagues at the Riddet Institute. The model is also part of masters programmes in nutrition and agriculture at Monash University in Australia and Wageningen University in the Netherlands.


Dr Smith says research has established that while the current food system produces almost all of the nutrients to meet the needs of a growing global population, we do not distribute these nutrients equitably. “The global food system is complex, varied and involves multiple inputs, outputs and feedback loops. Understanding it and identifying opportunities for improvement requires a comprehensive view of the whole system, including its nutritional, socio-economic and environmental dimensions. In testing changes to food production systems using the DELTA model, we can avoid falling short in delivering the micronutrients the global population needs.”


Dr Smith adds that current food production systems are under justified scrutiny from an environmental perspective and change needs to be made. “Both in New Zealand and globally, our food system is coming into sharp focus, particularly with a global pandemic and climate change shifting the way we think about and produce our food,” he says.


“New Zealand’s reputation for high quality premium food products needs to fit with the hungrier world of the future, and our penchant for innovation and ingenuity can certainly contribute significantly too. However, as we move forward to identify sustainable food production systems and food security, it’s essential that the nutritional implications of any change are not forgotten. 


“With the DELTA model, future food system scenarios can be investigated from a nutrition perspective alongside other aspects of sustainability – and this is more than just calories: the model considers the vitamins and minerals needed for good health and development; aspects not always considered in the sustainability debate.” 


Dr Smith and his team at the Riddet Institute continue to develop the DELTA model so that future versions will include the environmental impacts of food production, such as land use, to provide a more complete picture.


About the FAO: The international organisation leads efforts to defeat hunger and improve nutrition and food security. It’s Latin motto ‘fiat panis’ means ‘let there be bread’. The Riddet Institute’s perspective is: let there also be the DELTA model.


About the Riddet Institute: Headquartered in the Te Ohu Rangahau Kai building at the Massey University Palmerston North campus, the Riddet Institute has scientists across five main partner organisations: the universities of Massey, Auckland and Otago, plus AgResearch and Plant & Food Research, with several other universities also collaborating. 


The Institute is spearheading the conversation, positioning New Zealand’s agri-food sector as world-leading, informed and engaged. It highlights trends and opportunities in food for business and policymakers, promotes informed public debate on issues concerning food, its sustainable production and global food security, and endorses and supports the critical importance of science, science education and innovation in a rapidly changing world.

More information and access to the DELTA model can be found at