A team of researchers, including the University of Adelaide, has found most dietary recommendations provided by national governments are incompatible with global health and environmental targets such as the Paris Climate Agreement, and are in need of reform.
In the paper, published in The BMJ, University of Adelaide Health and Medical Science Honours student Luke Spajic worked alongside researchers from the Livestock, Environment and People program at the University of Oxford, and Harvard and Tufts Universities in the United States.
The researchers extracted the recommendations from the dietary guidelines of 85 countries, including Australia.
They modelled the recommendations against global health and environmental targets, including the goal to reduce premature mortality from non-communicable diseases by a third, and the agreement to limit global warming to below two degrees Celsius.
For comparison, the impacts of adopting the World Health Organization (WHO) global dietary recommendations, and the more comprehensive and ambitious recommendations of the EAT-Lancet Commission on Healthy Diets from Sustainable Food Systems, were also examined.
Spajic said they found that, on average, adoption of national dietary guidelines was associated with a 15 per cent reduction of premature mortality, and a reduction in greenhouse gas emissions of 13 per cent.
"However, a third of guidelines were incompatible with the global health agenda on non-communicable diseases, and between 67 per cent to 87 per cent were incompatible with the Paris Climate Agreement and other environmental targets," Spajic said.
"Taken together, 98 per cent of national guidelines were incompatible with at least one global health and environmental target, meaning that even if the whole world followed them, we would still fail to meet the targets governments have signed up to."
Spajic said that he was not all that surprised by these findings, as many national dietary guidelines in the study had not been updated for some time and did not include recommendations around environmental sustainability.
"In Australia, our dietary guidelines were last published in 2013, and absent from those are recommendations that factor in environmental sustainability," Spajic said.
Adoption of the WHO recommendations was associated with similar health and environmental changes as many national guidelines.
However, adoption of those of the EAT-Lancet Commission on Healthy Diets from Sustainable Food Systems, was associated with a third greater reduction in premature mortality, more than three times greater reductions in greenhouse gas emissions, and general attainment of the global health and environmental targets.
In Australia, adoption of the EAT-Lancet Commission on Healthy Diets from Sustainable Food Systems, could lead to a reduction in greenhouse gas emissions of 86 per cent, and a reduction in premature deaths of 31,000 (compared with 61 and 29,000).
Spajic says that Australia's national guidelines could be both healthier and more sustainable.
"We urgently need to update our national dietary guidelines to reflect the latest evidence on healthy eating."
"The impact of recent drought and bushfires in Australia has also added to the argument for environmentally sustainable recommendations to be included in our national guidelines."
"In Australia, we found that placing stricter limits on red meat and dairy would provide the greatest environmental benefit, and increased recommendations of whole grains, nuts and seeds, as well as further limits on processed and red meat would have the biggest impact on health," he said.
Dr Marco Springmann from the Nuffield Department of Population Health at the University of Oxford, who led the study says more ambitious guidelines on red meat and dairy would be a good starting point, however the guidelines are not a solution in themselves.
In the study, less than half of all countries with national food based dietary guidelines fulfilled any of their recommendations, and no country simultaneously fulfilled all recommendations.
"Food policies also need to encourage us to eat closer to national guidelines, and this includes investment in targeted public health campaigns that communicate what healthy and sustainable eating looks like," Springmann said.
The study also highlights the need for national food guidelines to be reviewed more frequently and compared to global health and environmental targets.