14 Jun Interpreting sustainable diet research
For many people, the term sustainable refers only to environmental sustainability. UN agencies now use the term “sustainable healthy diets,” to show the central importance of health and nutrition when talking about the sustainability of food. A recent review article wades through the mountain of research on such diets to find common approaches and conclusions.
The number of published studies exploring the sustainability of diets has surged over the past decade (Figure 1). The intended users of this research, often policy makers, may well be overwhelmed by this amount of information and the varied approaches to the same challenge.
The authors of this review were able to categorise the scientific approaches towards sustainable, healthy diets into 4 approaches. This categorisation should be useful to both research and interpretation, by explaining the scope and limitations of each.
The 4 categories were:
• examining the sustainability of hypothetical diets
• examining the sustainability of existing diets
• identification of existing “positive deviance” diets, i.e., studies that examine a range of existing diets and identify the most sustainable among them as possible targets
• designing more sustainable diets with optimisation
No approach is perfect, but the authors do note that the final approach, optimisation of diets using modelling, is the only approach where nutritional adequacy can be ensured. However, general acceptability of such optimised diets is not assured. SNi® will soon begin work on an optimisation model that will include the acceptability of diets in the optimisation.
The authors used their categorisation on more than 50 studies and found that the vast majority fit within their framework. They also provided advice for decision-making by public and private stakeholders on the strengths and weaknesses of each classification, with the aim of facilitating better recommendations, interventions, and public policies.
The classified studies confirm that it is possible to reduce the environmental impact of diets while improving their nutritional quality. However, the authors note that sustainable diets are only one part of a sustainable food system. They emphasise the need to be holistic and address both production and consumption, as well as all the food system steps that sit between and around these processes.