While the idea of eating insects may repulse some people, eating animal products from livestock reared on insects may be less off-putting. Black soldier fly larvae are an insect often produced as feed for livestock, and a recent research article has examined their potential in converting food waste to feed at scale.
Food waste represents lost inputs and value as well as having negative impacts of its own. While reducing food waste is an ongoing challenge, the production of some waste is inevitable. While we commonly think of food waste at the consumer or retail level, losses also occur higher up the supply chain with the producer. For many crops, such as soy and maize, only a few percent of the total production mass entering the human food supply chain are wasted, but this still amounts to millions of tonnes of plant matter globally each year. Conversion of this waste to animal feed is one way to include food waste in a circular economy, and to approach a zero waste system.
Some of the advantages of farming insects on food waste include the ability to co-locate production centres of any size locally to either food waste production or to the farms that will use the feed, due to the flexible growing conditions of these insects. Insect production near crop production has the added advantage that compost – the by-product of insect farming – can be returned to the field as fertiliser.
The yield of larvae for feed from food waste is up to 12%, over a period of as little as two weeks. The larvae are also a high-quality feed, with protein contents of 32-58%. In the case of many commercial aquaculture fish species, they can be a complete feed replacement.
The authors conducted an exploratory life cycle analysis of a hypothetical UK scenario where a large portion of food waste was diverted to insect production. They found that this resulted in a reduced environmental impact compared to biogas production from food waste for indicators such as global warming and land use, but greater impacts for indicators such as water consumption. The environmental impact of larvae production could be further slashed if electricity consumption were reduced or sourced renewably.
Commercial operations are already exploiting the larvae opportunity. In the UK, deals have been struck between supermarkets and insect farms to produce chicken feed from retail food waste. Elsewhere, “the world’s largest insect farm” has been proposed in the US, co-located with a large pet food factory.
Valorising unavoidable food waste and keeping the benefits within the food system has strong potential. Building such possibilities into food system models such as the DELTA Model® will allow their global potential to be better understood.
Tracking population dietary habits is notoriously difficult, from cohort recruitment to the patchy recollections of what someone ate 24 hours ago. A recent article in Nature Communications approached diet studies via a freely available smartphone app, allowing a large cohort to be assessed with minimal commitment from the participants.
Data from over a million app users, who added on average nine entries to their digital food record each day for an average 197 days, was matched up with demographic and location data to understand the consumption habits of a US cohort.
Their results matched existing knowledge on food environments and dietary habits: high income, higher education, high supermarket access and low fast-food access (the latter two determined by location), all correlated with lower BMI, higher fruit and vegetable consumption, and lower fast-food consumption. One exception was a slight association between high income and high BMI.
The authors also matched their location data to the predominant ethnic group, which was possible due to the zip code level resolution of the data. Again, these results reinforced existing data on the prevalence of consumption of specific foods, and the prevalence of obesity, but across a broader area than previously possible.
This paper shows the power of repurposing existing digitalised data for nutrition research. Such large, long-term, detailed sampling of the US cohort would have been extremely challenging without the availability of an already popular app. Moreover, the privacy of individuals was protected, and the app developers donated the data from the research, facilitating a more refined understanding of their nutrition.
Many researchers have proposed scores and methods for reducing the nutritional value of foods down to a single number – as covered in a recent Thought for Food. A new method takes an approach rooted in population dietary intakes.
There are many challenges to this: which nutrients to include? How to weight components without introducing bias? A recent paper has avoided these issues by including all nutrients in the Australia and New Zealand Nutrient Reference Values, weighted by the degree to which the Australian population under- or overconsumes them.
The NRF-ai metric (Nutrient-Rich Food Index – adequate intake) means that foods containing under consumed nutrients like calcium, magnesium, vitamin B6 and zinc will receive higher scores than those containing the same amount of vitamin C or phosphorus, which are consumed at adequate levels by most of the population. Conversely, foods containing free sugars will be penalised, as intake of these is above recommendations in most populations. The score can be made specific to age and gender groups, as the prevalence of deficiency for each nutrient varies between these groups. Ultimately, this leads to a metric that ranks a food item on its ability to address the nutritional needs of the population.
There are many applications for this metric for comparing foods. In the paper, the author considers the score per $ retail price, to understand the cost-effectiveness of a food for meeting nutritional needs. Per environmental impact examples are also given.
NRF-ai represents an unbiased approach to reducing the nutritional value of a food down to a single number. While this approach still loses information compared to the full nutritional composition, it is still valuable for comparisons between like products. A similar approach is applied by the DELTA Model® for the nutritional value of food items for meeting global nutrient requirements.
We previously described the results of a modelling study that found the least cost nutrient adequate diet in the USA came in at US$1.98, and the equivalent least cost plant-only diet was $3.61. The authors of that study have now repeated their work with New Zealand data, reaching similar conclusions.
Linear programming was combined with supermarket food price data, food composition data and adult nutrient requirement data to find daily diets that met all nutrient requirements, optimised for cost.
Similarly to the original USA study, the least cost diet contained both plant- and animal-sourced foods. At NZ$3.23, the price difference to the plant-only diet (NZ$4.34) was reduced compared to the USA results.
In both the NZ and USA diets, milk was a large contributor to nutrient targets in the least cost diet. A soy beverage was the largest contributor to both mass and cost in the plant-only diets. Eggs, legumes, and cabbage were also important in both country settings. While fish was present in the USA least cost diet, this was replaced with green mussels in NZ.
The relative changes to the price of animal-sourced foods before they became priced out of the least cost diet differed between the two settings. Milk was removed when its price was 2.2x current NZ retail price (compared to 8x in the USA study); eggs under price increases of 1.8 times (11.5x in the USA study); and meat items under price increases of 1-2x (3-5.5x in the USA study). In contrast, the mussels remained in the least cost diet even if ten times more expensive than current prices.
This work reinforces the conclusions of the original paper: plant- and animal-sourced foods contribute to affordable, nutritious diets, and it can be more expensive to achieve adequate nutrient intakes if restricted to plant foods alone. However, the reduced resilience of most of the animal-sourced foods to price increases in the NZ setting is reflective of the differing relative retail prices of food in the two countries, which the authors state may be reflective of the influence of government subsidies in the USA.
The future of the food system is a major topic of conversation with various voices advocating the need for a range of changes, with some being quite radical. Historically the focus on the global food system was on providing enough nutrition for those in most need. This has transitioned to many advocating a need for the food system to change to address issues that are a consequence of wider human activities.
When we talk about the food system what are we referring to? What are we talking about changing? And how do we understand the potential impact of changes? This Thought for Food considers three different scales at which we can consider questions around the food system and the work the Sustainable Nutrition Initiative (SNi™) is doing to support this, in line with our recently adopted vision “evidence for sustainable food systems”.
Conversations about the future of food usually fit within one or more of the following areas:
Nutritious, affordable and sustainable diets for individuals
National use of environmental and other resources for food production
Sustainability of global food production and distribution of food to address the nutrient needs of everyone
Each scale has its own unique questions and challenges that need to be understood and addressed.
At the global level…
We will start with the large scale first. How does the world feed the world?
What food production is required to provide adequate nutrition for everyone?
How does this change as global population continues to increase?
What are the resource implications of this at a global level?
What are the impacts of large-scale changes in food production?
How big are the changes needed to be globally relevant?
In one sense the global scale question is easier to frame than the two smaller scales. There is only one Earth – there are no interplanetary trade flows to cover shortfalls or utilize surpluses – everything must balance within the planetary boundary. The total nutrition available is determined from the production of food commodities, and further processing and food formulation is largely a reorganization of the form in which these nutrients are presented to consumers.
The DELTA Model was developed to contribute to this global scale conversation by enabling a user to set the level of production for the major classes of food commodity and see the likely impact of this on nutrient supply for the global population. When we consider making changes to production on the global scale, we must also match this with an appropriate timeline of multiple years. The original version of DELTA provides significant insight on the role of the different primary production systems in providing nutrients to the global population (learn more here). A key conclusion from all our work to date with DELTA is that the global food system is, and must remain, “plant based and animal optimized.”
Further development of DELTA focuses on adding estimates of resource footprints for the selected production systems, starting with cropland use in DELTA 2.0 (learn more here). Consistent with the scenario “what if” concept of DELTA, the model does not enforce a hard constraint on production based on available land, but instead provides feedback to the user on the extent to which their proposed food system is feasible within the land area suitable for crop production.
Beyond 2.0 we will introduce additional resource footprints into DELTA, including greenhouse gases and the use of land for ruminant grazing. At the same time, we are looking at how we make better use of the more detailed food commodity and use data made available by the FAO towards the end of 2020.
An aspect that was part of the original concept of DELTA was to consider economic aspects of the food system. A key challenge that is neglected in the discussion of many high-tech alternatives is the level of capital investment required to establish these technologies at a scale that would make a material impact on global nutrient supply, and the implications of this for the cost of the resulting nutrition (learn more here and here).
At the individual level…
At the other end of the scale is individual dietary choice.
How can individuals within our society access the nutrients they need?
How is this impacted by the price of food items?
How do their choices impact on the environment?
How do choices potentially alter health outcomes?
These are questions that individuals may ask for themselves and are also relevant in the development of public policy. Potential outcomes include changes in dietary guidelines or changes in individual eating habits.
There is considerably more scope for an individual to change their diet than there is for change at the global scale. At the individual level a radical shift in diet may be made quickly and has no discernable impact on the food production system and supply chain. It is only when large collections of individuals make similar changes that this has an impact on the availability and affordability of food items, and the feasibility of these choices (learn more here). Whilst the global nutrition question is constrained by the boundaries of the planet, the individual nutrition question is limited by the range of foods available locally, and the wealth and choices of the individual.
Riddet Institute researchers used linear programming to determine the minimum cost for a nutritionally adequate diet based on a basket of food products in the USA (learn more here). Work in the Netherlands led to the development of Optimeal™, which starts from the Dutch reference diet and explores the impact of restricting the intake of certain foods on the carbon footprint and price through an optimization that seeks to remain close to the reference diet in terms of foods eaten thus addressing some of the cultural aspects of dietary change (learn more here).
Building from these ideas we aim to create an online tool to enable people to explore individual dietary choice, what levels of dietary change may be possible and practical, and the resulting impacts in any country for which the required food product information is available. The aim is to make it easy to customize this for use in any country for which the required food product information is available. Unlike DELTA, where the default time is currently 2018 for the base case and 2030 for the initial projections, the individual model (to be called IOTA) will work in an immediate sense (i.e., If I changed my diet today…).
At the national level…
In between these two extremes sits the national level question:
What is the best use of our natural resources?
How should we best utlise our land?
What should we grow or produce ourselves?
What do we export? What do we import?
How does this influence our environmental impact?
This is more complex than either the global or individual scales due to the movement of food items across borders. Food trade exists at some level for almost every country in the world: there is not the same hard boundary that exists on the global scale (i.e. only one planet) that requires domestic self-sufficiency for any given nation. Nutrient gaps can be addressed through imports and surpluses addressed through exports – although this only partially occurs today. Food trade occurs when one nation has to offer what another wants, so the options are constrained, although wealthier countries are better able to purchase what they want. As the DELTA Model shows at a global level, we already produce enough food energy and protein to meet the needs of the expected 2030 population, however not everyone has equal access.
Our current work at the national level is to understand the present state of food production and trade flows expressed as bioavailable nutrients rather than mass of food items. This provides a human nutrition centric perspective. The following charts from DELTA show, from a food energy perspective, the production, trade flows and consumption for New Zealand, Australasia, and Oceania.
The “Produced” column shows the per capita per day production of energy in the country or region. Oceania is dominated by the food exporting nations of New Zealand and Australia and there is a considerable surplus of food energy at both the regional and sub-regional scales. However, when we just look at New Zealand, we see a significant import of plant-based food energy. Similar charts are available for all 29 of the nutrients considered in DELTA, in all countries. Taking this a stage further, with our collaborators at University of São Paulo we are looking at flows of bioavailable nutrients between exporting and importing countries to show the evolution of the trade network.
Whilst the above helps to understand the current state of nutrient flows, it does not address the questions about most effective use of a country’s resources (environmental, social, economic). To do this, we are developing a proposal for multi-year research to investigate the national and sub-national questions, using New Zealand as a test-case. This will lead to the development of an integrated model framework that connects primary production and food trade decisions with their associated resource and economic implications, through to consumer nutrition and associated health and wellness outcomes. The objective is to develop a model that works for New Zealand and can, through changing the data inputs, be applied to other countries.
As with DELTA, the approach will be scenario-based, with users specifying a potential system and the model estimating the implications of this system in terms of the various capitals. By doing this we hope to contribute additional evidence-based insights to national and local conversations about food systems.
All three scales are important and complementary
The food system must function at all scales from the global, through the national, to the individual level. Each has unique characteristics and challenges that impact on our ability to make changes. Aspects that are easy at one level, create complications at another.
Importantly, no one perspective will deliver a full understanding of the food system and the way forward to greater sustainability.
An individual’s diet that is healthy, affordable and has a low environmental impact will not necessarily be applicable more widely.
National level food preferences and cultures, as well as what can be produced in a country, will mean that variation must exist between healthy and sustainable diets and food production in different parts of the world.
Similarly, it is not sufficient to understand what sustainable dynamics are for a single country, as countries do not operate in isolation: international food trade and global production must also function sustainability.
SNi is developing tools to help people explore food system challenges and provide evidence for sustainable food systems at all three scales.
A report co-produced by the FAO, UNDP and UNEP has analysed current levels of agricultural support (such as subsidies, tariffs, and incentives) in 88 countries. Their finding was that the majority of the total support value could be considered harmful, largely through distorting food prices, indirectly promoting unhealthy diets, or damage to the environment.
Around US$540 billion, or 15% of the total value of agricultural production, is paid out in agricultural support each year. These funds are split almost equally between farmer subsidies (reducing the cost of agricultural inputs or rewarding production of specific commodities) and price incentives (tariffs or subsidies on trade). A small proportion goes towards non-specific, general sector services, such as agricultural training, infrastructure development and product safety.
The authors state that over two thirds of agricultural support has the effect of distorting food prices and increasing the environmental damage of food production. This is often embodied in support for production of foods with low nutritional value (e.g., sugar cane) or high carbon emissions (e.g., ruminant meat).
Most agricultural producer support is currently focused on specific commodities. The foods receiving the greatest support were sugar, animal products and cereals, with cotton a highly supported non-food commodity. Developing countries tend to predominantly subsidise production of staple crops, whereas animal-sourced foods generally receive greater support in developed countries.
The report pushes not for the elimination of agricultural support, but rather its repurposing. This topic was also discussed at the UN Food System Summit in September 2021. Many parts of the food system have evolved some degree of dependency on the current support structures, so any changes must be carefully made to avoid unintended consequences. Consumers need access to affordable healthy diets, but producers also need to be assured of an income. The authors’ general conclusion was that agricultural support should enable environmental, health, and social progress, as well as economic gain.
Earlier this year, the FAO reported the highest global food prices in a decade, driven by a collection of factors. The economics of the food system play an important role in sustainable nutrition, but can be challenging to understand or influence given the complex system that they operate in.
The FAO Food Price Index measures monthly changes in the international prices of a selection of food commodities. The index combines global price data for 23 widely traded food commodities, including cereals, dairy products, meat products, sugar, and a number of vegetable oils, weighted by the average export share of each commodity group. The resulting index score gives an indication of global trends in food prices.
The Food Price Index in October 2021 was up nearly a third on the previous year. This has been largely driven by cereals (22% year-on-year increase) and vegetable oils (reaching an all-time high). Dairy, meat, and sugar were also up 15-40% on 2020 index values.
Cereal use is forecast to slightly exceed production over the coming year, leading to a slight decrease in global cereal stocks and the resulting change in supply/demand ratio that influences price. The forecast also predicts record high levels of international cereal trade, at 478 million tonnes annually, out of a total 2.8 billion tonnes produced.
Changes in international food prices are driven by a variety of inter-related factors. Some recent factors include reduced harvests in major cereal and sugar producing regions, migrant labour shortages in vegetable oil producing countries, and increasing fuel prices.
The complex economics of the food system are challenging to unpick, but play a central role in the delivery of food and nutrition to the global population. It is important to consider the balance of input costs, output value and demand when thinking about the future global food system. Increased trade demand, reduced harvests and external costs all have an impact on retail food prices and availability, with implications for consumers. A sustainable food system must be holistically sustainable, and economic sustainability is a key part of this.
The Good Food Institute recently commissioned a techno-economic analysis projecting the future costs of producing lab-grown meat, that has since seen backlash as lab-grown meat’s inevitability is put to question.
The report models the cost of producing lab-grown meat at industrial scale following various future scenarios to build a timeline out to 2030. The modelling illustrates diminishing costs from a current baseline using data from 15 companies in this field. Currently, production prices are over US$22,000 per kg of product. If significant technical and economic barriers were addressed, the report estimated the cost could drop to $6.43 per kg in 2030. The report provides a positive outlook on the future of lab-cultivated food products being economically accessible and technologically viable.
This has seen backlash by experts in the fields of biotechnology and economics. Overcoming the barriers required to scale-up this technology and realising the stated cost reductions have been labelled as “very theoretical”, over-reaching biological limits, and underestimating the costs involved. For example, it would cost an estimated $1.8 trillion to build the facilities required to produce even 10% of the current meat supply.
These findings exemplify the caution that must be taken when considering media articles and the claims of biotech start-ups, projecting a future and timeline for lab-grown meat that drives interest in the technology. Although these technologically-derived products may support a sustainable food system in the future, the significant challenges this sector faces indicate that we must focus on the efficient use of current resources today, without relying on the future potential of such technologies.
Individuals are increasingly concerned about the environmental impacts of their food choices. A recent paper in Sustainability quantifies the global warming impact of several NZ diets over the entire lifetime of the consumer, providing context for the role of diet in an individual’s overall contribution to global warming.
How can we eat healthier diets that still satisfy us, which don’t cause excessive damage to the environment, without breaking the bank? Questions like this have arisen in the minds of most conscientious consumers at some stage, but there is little consensus on what such a diet might look like in the nutrition field.
Prioritising any factor – health, taste, price, or environmental impact – depends on the values of the individual. However, when we fail to adequately consider health and nutrition, the risk to the individual is high.
On this topic, the Riddet Institute’s Sustainable Nutrition Initiative team were recently involved in a multi-organisation international project calculating the global warming impact of various New Zealand diets.
The research took the current average NZ diet and calculated what the global warming impact of this diet would be. In a point of difference to much other work in the field, the cumulative warming impact was calculated over the entire lifetime of an individual, rather than shorter term impacts. The calculation was repeated for a NZ diet that follows the national dietary guidelines, and a vegetarian NZ diet with no meat content. Each was designed to reflect realistic choices that a NZ consumer might make.
The results show that a move from the average diet to one that adheres to the NZ dietary guidelines would have benefits both to nutrition and global warming impact. Similar results have been found in many other studies (see here, here, and here), so this was not surprising. In this research, the reduction in the global warming impact of the dietary guidelines diet was 7-9% compared to the current average diet.
Transitioning to the no meat diet showed a reduction of 12-15% in the global warming impact of the diet compared to the average NZ diet, so an additional reduction of 3-8% compared to the dietary guidelines diet. However, in the context of an individual’s total warming impact from all consumption (i.e. including things like transport and heating), switching to the no meat diet at age 25 was calculated to result in a 2-4% reduction overall. This relatively small result is because diet is only one part of our global warming impact, accounting for about a quarter of consumption-based emissions for the average New Zealander. As a comparison, transport is on average around 35% of NZ consumption-based emissions.
Consumption-based emissions differ to production-based emissions. Production-based emissions are those produced within a country, without accounting for how goods are traded across the world. Consumption-based emissions take account of the trade of goods, allocating emissions to the end user based on the products they consume. This choice is particularly important in countries like NZ, which export and import large proportions of the food they produce and consume.
Bringing in the cost side, other NZ research has also shown that dietary guidelines, flexitarian and vegan diets can have reduced greenhouse gas emissions, but that the price also rises as the diet moves further from the current average NZ diet. Thus, such changes will be less achievable for individuals with less to spend on their food.
Clearly, there are a number of ways that concerned individuals can reduce their warming impact, such as changes to transport, heating and recreational choices. Diet is one of these options, but these choices must be evaluated on their efficacy.
This research is important in providing context for the contribution of diet to an individual’s global warming footprint. Most importantly, a transition towards the recommendations of the dietary guidelines was a win-win for both nutrition and global warming footprint.
However, in the context of an individual’s overall lifetime global warming impact, it is important to realise that changes to diet made only a minor difference.
The NZ context of this work is also influential. Over 80% of NZ electricity generation is from renewable sources, which reduces the global warming impact of the NZ energy sector. As such, many activities in NZ (such as heating or manufacturing) have a lower warming impact than they would in other parts of the world. Similarly, many parts of the NZ agriculture sector have lower carbon emissions per kg of product than seen in other parts of the world. Therefore, the percentages above are likely to differ in different parts of the world.
A key takeaway emphasised by this research is the need to prioritise considerations of nutrition and health when thinking about our own diets. One of the important things to note from this paper is that the diets considered were not nutritionally equivalent. Moving from the average NZ diet to the dietary guidelines diet largely meant increasing fruit and vegetable content and reducing discretionary foods. There were some smaller increases in certain dairy products and decreases in some meat products. The result was a diet with improved availability of calcium, fibre, folate, and magnesium.
The no meat diet was not equally win-win: while it had a reduced warming footprint and was broadly similar in its nutrient availability to the dietary guidelines diet, its iron content fell short of the average adult’s daily requirement.
The nutrient differences are more pertinent to consumers than the small calculated global warming impact. Changes to the foods in an individual’s diet result in changes to the amount and sources of the nutrients they consume. It is essential that, when considering changes to diet motivated by external factors such as global warming impact, individuals are aware of the nutritional changes they will also be making. These changes may have large positive or negative impacts on health and wellbeing.
Adequately nourishing the global population is a key component of sustainability. A food system that does not deliver nutritious diets to all cannot be considered sustainable, regardless of its social, economic or environmental sustainability. It is essential that, when we are considering the environmental aspects of diet, such as the lifetime global warming impacts (as calculated in this paper), that we do not ignore the nutritional adequacy of different diets.
The Riddet Institute is this week hosting an event to bring together food system stakeholders and decision makers for accessible evidence-based discussion of the key global issues and the local decisions that we need to make.
Sustainably feeding a growing population is a global problem, but also one for New Zealand to consider. Where does our reputation for high quality, premium food products fit in a hungrier world? How can kiwi innovation and ingenuity make a difference to the global future of food?
The event will explore the current conversation of sustainable food, bringing moderation and balance to what is often a debate of extremes. National and international experts in the fields of nutrition, food waste, food systems, life cycle analysis and consumer science will speak on these important issues, with open discussion from the attendees.
This dialogue will inspire our future decisions and put New Zealand at the front of the sustainable food systems debate.
