Three scales and four aspects of sustainable food systems

Three scales and four aspects of sustainable food systems

In a previous Thought for Food article, we explained the three scales at which SNi® approaches the topic of sustainable nutrition: global, regional, and individual. However, in addition to these scales, it is also necessary to understand what aspect of food is being addressed: are we considering the production of commodities or food items; the role of meals or of diets? This article explores the importance of this framing for better discussion of sustainable nutrition.

Boundaries on three scales

SNi® research and much of the existing literature on sustainable nutrition can be categorised by the boundaries used. Much research exists on identifying sustainable, healthy diets for individuals. As discussed in a recent SNippet, these approaches take a number of forms, including computational optimisation of diets to achieve nutritional adequacy and improve environmental credentials. This is the approach that will be taken by the iOTA Model®, currently under development by SNi®.

Another scale to address is the sustainability of the global food system, and how it may change in the future to improve the delivery of nutrition to the global population, mitigate environmental harms, and address other sustainability goals. The DELTA Model® uses this global boundary, and as such tells us little about diets for individuals.

The final scale sits in between the individual and global: a regional boundary on food system sustainability, and population nutrition. The region and population in question may vary in scale: some researchers have investigated the sustainability of the European food system, while others have looked at national systems. SNi® is leading the development of a national food system scenario model for New Zealand, that will allow the impact of future changes to the system on several aspects of sustainability to be simulated. Research at this scale is challenged by the need to consider flows both in and out of the boundary, and the forces that determine these flows e.g., if the boundary is a country, then international trade would be an essential flow to consider.

Defining the boundary of study is essential, but it is also important to understand how we are thinking about food within that boundary.

Introducing four aspects of food

In the field of sustainable nutrition, food is usually the subject under study. But food must be looked at from different aspects depending on the questions being asked. Someone interested in food production would be concerned with food commodities, such as wheat, whereas a population nutritionist might consider bread availability, and a dietician would be interested in the role of bread consumption in the diet of individuals.

The four aspects we have identified are:

  • Food commodities: the original form of food as produced, often before processing into food items for consumption, e.g., wheat, avocados
  • Food items: food in the form it is consumed, e.g., bread, avocados, pizza
  • Meals: the combination of food items consumed in one sitting, e.g., avocado on toast, pizza
  • Diets: the combination of food items and meals over time, e.g., avocado on toast for breakfast two days a week, in combination with diverse consumption of other meals and food items
You will note that some food commodities can also be food items (avocados in the above examples), and some food items can also be meals (pizza in the above examples). There is overlap between aspects, but each aspect is meaningful for certain approaches to sustainable nutrition.

The use of aspects and scales is context-dependent
When examining the production or harvesting of food, discussion of food commodities is key. Researchers may be interested in maximising production, investigating food trade, reducing environmental impact, or economic aspects of production, all of which require an understanding of commodities. Food commodities are most relevant to global or regional scale approaches; at these scales, meals and diets are extremely diverse, so it is more insightful to consider food commodities or items.

The disadvantage of considering food commodities is how far removed they often are from food consumption.

For example, the DELTA Model® considers the nutrient content of food commodities and unformulated food items, and compares these to population nutrient requirements. This approach does not incorporate the impact of extensive food formulation, or combinations of items into meals and diets on the nutritional value of food. For instance, consumption of foods rich in phytic acid can reduce the absorption of certain minerals, but these dynamics cannot be captured in the commodity or item aspect.

The food item aspect can be of use when examining supermarket food availability, for example. This might be at the regional scale (e.g., what is the impact of a sugar tax on the retail price of foods?) or from an individual (e.g., what is the price implication to the individual of choosing to purchase solely organic products?). However, once again the food item aspect will not capture meal effects, and will also not be useful for understanding the production of the food commodities used as ingredients in formulated food items. 

Meal and diet aspects also fill quite distinct roles. A single meal may be completely lacking in dietary fibre, for example, but this is not necessarily of concern if the diet of the individual usually contains high fibre. Conversely, national dietary guidelines must make consideration of the meals that the population consumes if they are to be acceptable, and therefore sustained.

Approaches to sustainable nutrition can cross multiple scales and consider multiple aspects.
One example of this is the EAT-Lancet Commission on healthy diets from sustainable food systems. These researchers recommended a diet, but also discussed what a global shift to that diet would mean for global production of food commodities. An area on which this work has been criticised is its applicability to the regional scale.

In the other direction, a DELTA Model® user might define a global scenario where sugar production is halted, but must then consider what this will mean for the changes to the food items and meals consumed by the global population, as well as for regions that currently produce sugar crops.

Nutrition should be considered at all scales and in all aspects
Sustainable food systems and sustainable, healthy diets both have nutrition as a core part of their definitions. If good nutrition is not achieved, neither is true sustainability.

There is great importance in defining the boundaries and the aspect of any approach to sustainable nutrition. This allows the limitations of the approach to be clear to all. It also forces us to think about what our conclusions mean beyond the boundary and aspect of our approach.

A truly sustainable solution must meet nutritional needs when considered at all three scales and for all four aspects of food.

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