Adding value with bugs 

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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.

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Evidence for Sustainable Food Systems at Three Scales

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.


Need or Greed?

Adjunct Professor of Massey University and the Riddet Institute and Fonterra Chief Science and Technology Officer, Jeremy Hill, last week contributed to COP26 on the future of sustainable food systems. SNi research featured heavily in this contribution. Prof Hill outlines some important aspects of today’s food system that are poorly understood, and examines the role of meat, dairy and future protein sources in achieving sustainable nutrition.

The global food system

SNi work on global food biomass production and nutrient availability has shown that the current global food system is already plant-based, but with animal-sources of nutrition playing a vital role in overall nutrient provision. Of the 10.6 billion tonnes of food biomass that left the world’s farms and oceans in 2018, 9.2 billion tonnes (87%) was plant material and 1.4 billion tonnes (13%) was animal-sourced. On a global basis we have mapped the flow of this food biomass, shown in the below figure.

Biomass flows through the global food system.

On a simple biomass basis, 1.4 billion tonnes (15%) of human-edible plant biomass leaving the world’s farms was used as feed for animals, to supplement non-human-edible feed such as grass. This was used to produce the 1.5 billion tonnes of animal-sourced food leaving the world’s farms.

At face value, this does not look very efficient, considering the environmental impact of animal production systems. However, this hides the different nutrient contributions that come from plant and animal sources of nutrition, land use suitability for cropping and major differences in the supply chain losses, waste, and non-food uses of the plant and animal contributions to the global food system.

The fact that only 1.4 billion tonnes of human-edible plant food biomass was used to feed animals also highlights that a significant proportion of animal nutrition does not come from human-edible plant material but from straws, silages, pastures, food waste, and so on. The scientific publication: Livestock: on our plates or eating at our table? provides an excellent overview of the feed versus food debate and found that, although livestock consume one third of global grain production, 86% of the biomass consumed by farmed animals is inedible for humans.

75% percent of what is eaten by the global population comes from plants; but also, 91% of post-farm food losses and waste comes from plants.

Of the food material entering the food chain, 86% of animal-sourced food material produced is consumed but only 47% of the plant-sourced food material.

Looking at global food supply, flows, consumption, and losses gives a different perspective on efficiencies. The food system is already plant-based and from the perspective of production, consumption, and waste, animal sources of food have very efficient aspects. But that is the case for food biomass; what about nutrition?

Nutrition supply and demand

We often hear about the “need” to produce more protein to meet the growth in demand for protein-rich foods. This includes the “need” for more meat and that using current systems to produce this amount of meat is not sustainable. We have recently shown using the DELTA Model for global nutrient provision that the world not only produces enough protein to cater to the nutritional requirements of our current global population (see below figure), but that current production could meet the protein and indispensable amino acid requirements of a population projected to reach almost 10 billion by 2050. The issue is not production but distribution, access, and affordability of protein.

A value of 1 indicates that global nutrient availability exactly meets requirement, less than 1 a shortage, and greater than 1 a surplus. The coloured bars show the global average nutrient availability. Red bars indicate nutrients with insufficient availability, orange bars are just meeting requirement, and green bars clearly exceed the target. The error bars show the range in nutrient availability between the 10 th and 90 th population percentiles based on country level averages. 

In contrast to the global availability of protein, there are currently large gaps between global need and global supply of certain micronutrients that will only get bigger unless the food system changes to address these gaps. Critically, animal-sourced foods and oil crops are currently the major sources of key micronutrients in deficit, such as calcium and vitamin E, with animal-sourced foods also important sources of globally limited nutrients such as iron, zinc, potassium, vitamins A, B2, and B12.

For most nutrients there is a wide variation in their availability between countries, and clearly for some countries, access to sufficient nutrition drops below target intake (see above figure). These gaps have the potential to increase with an increasing global population and especially if, as is currently the case, the population increase is in countries where access to nutrition is already below target requirements.

‘Meating’ needs?

Thinking about the current growth in meat production: how much of this is meeting needs rather than catering to the greedy? Here I use the term “greed” in the context of eating a particular food beyond the point of its contribution to a balanced diet and nutrient requirements, with no implication of moral judgement. Nevertheless, it is hard to argue that this behaviour is in keeping with sustainability, as over-consumption can be considered a form of food and nutrient waste.

According to the FAO, global meat production grew 44% over the period 2000-2019. But how much of this growth is servicing need rather than greed? How many of the existing or new consumers are eating meat above the recommended target intake? Quite a considerable number according to The Global Burden of Disease Study (see below figure). Yet, as with overall protein availability, the consumption of meat is geographically uneven.

The dotted line represents global average consumption levels and shaded green area the uncertainty in the level of optimal intake. Reproduced from Afshin et al. 2019 under the CC BY 4.0 license.

Milking the planet?

At 844 million tonnes, milk represents 60% of the animal-sourced global food biomass. So how does its consumption compare with meat? Clearly the picture for milk is very different, as is calcium intake (see below figure), with the per capita consumption of milk falling short of optimal intake in all regions of the world.

The dotted line represents global average consumption levels and shaded green area the uncertainty in the level of optimal intake. Reproduced from Afshin et al. 2019 under the CC BY 4.0 license.

Our work at SNi has found that although milk represents 60% of animal-food biomass, milk is less than 8% of the total food biomass leaving the farm gate, and contributes 49% of the calcium, 24% of vitamin B2, 22% of vitamin B12, 15% of vitamin A, 12% of the protein, up to 18% of the indispensable amino acids, and makes a significant contribution to a range of other nutrients consumed by the global population. Moreover, at only 7% of global dietary energy, milk is not only nutrient rich (content and range of nutrients) but also nutrient dense (content and range of nutrients compared to number of calories).

Clearly milk plays an important role in global nutrition and from a consumption versus recommended intake perspective, it would appear we should be producing more milk not less. But that’s nutrition and health, what about environment?

Although the food system in its entirety is estimated to contribute 20-30% of total GHG on a carbon equivalent basis, dairy’s contribution is 2-3%. Considering milk’s global nutrient contribution, its nutrient richness and nutrient density, dairy looks like a pretty good deal. A good deal, but not a perfect deal and, for the very reason that it is so important to global nutrition, we should focus on making large improvements to the efficiency of milk production and its environmental footprint, especially if we need to produce more rather than less milk in the future.

Alternative Reality?

Of course, another often publicised approach would be to attempt to replace milk and other animal-sourced foods with alternative sources of nutrition that have lower environmental footprints.

As discussed earlier in the article, the issue with global nutrition is largely about affordability and access, i.e. what the global population needs. As such ‘plant-based’ alternatives and new technologies, such as precision fermentation or mammalian cellular production, should aim to produce substitutes in more affordable and accessible formats that provide the same nutritional benefits as existing plant and/or animal sources of those nutrients.

We would also argue that improvements to the productivity and sustainability of existing plant-sourced or animal-sourced foods should look to do the same.

Whether consumers of such alternative and novel foods are actually doing good rather than just feeling good about what they are doing will depend on several factors.

  • What does this consumption mean for global food biomass production, losses, and waste?
  • Are the alternatives as nutritious as the foods they are substituting?
  • Do the alternatives have lower environmental footprints for water, land use etc. as well as just greenhouse gases per unit of nutrition?
  • Are the alternatives consumed responsibly to the point of need and not well above what is required, as a result of “greed”?
  • Are the alternatives cheaper to produce and distribute and can they be sold in such a way that it increases global access to nutrition?
  • Will companies producing alternative proteins transform the global food system by democratising it and providing more access to affordable nutrition? Or will they concentrate control and remain beyond the reach of many global consumers?

SNi was established to help create a better understanding of the global food system and particularly the critical issue of how it can provide all the nutrients required by everyone on the planet. Its purpose is to help people explore what changes to the system may be possible, but also what will be practical.

If we are to have a sustainable world and, by implication, a sustainable food system, then there is certainly the need for radical change. However, we do not subscribe to the view that all aspects of the food system need to be disrupted. Radical improvements in the existing food production system will be equally, if not more important, than radical changes to the food production system.

But to be clear there will be no room for laggards, and we do see an important role for new ways of producing the nutrients we require, such as precision fermentation, but that these will be complementary to rather than totally disruptive to existing food chains. In doing so everyone has the right to choose the diets they want to follow and certainly for those that can afford to do so, have broad options for what they can choose.

When it comes to the food system, perhaps the most important changes of all are the changes we make ourselves. Here I would start with consuming closer to what we need and cutting back on the greed.


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Apocalypse Cow

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In the scramble to reduce greenhouse gases (GHG) quickly, a world without methane producing cows is one of the more extreme solutions that has been explored. Inspired by the large-scale change on our environment caused by COVID-19 restrictions, a unique study in Nutrition Today has considered the impact of a dairy-free world.

This study assesses the impact of removing all dairy cows from the environment, with a focus on three areas: nutritional, environmental and economic.

  • Nutritional impacts: Removing one of the most nutrient rich food sources would have dire consequences in a world where an undersupply of micronutrients is already a significant challenge. Although some individuals could, and do, cope without dairy, many countries that rely on dairy as an essential source of nutrition would see increasing cases of hunger and deficiencies e.g. India who already see 70% of the population suffering from some degree of protein calorie malnutrition
  • Environmental impacts: Taking away a methane producing source will inevitably reduce GHG emissions. Elimination of all global dairy and associated meat production would reduce GHG emissions by 4% on a carbon equivalent basis. Whatever nutrient source took its place must emit less than cows milk for the benefit to be realised.
  • Cultural and economic impacts: Roughly 1 billion people and their communities rely on dairy farming for their livelihoods and economic foundation.

This assessment was carried out by authors from Global Dairy Platform, so an implicit bias to dairy exists. The pros and cons of supplementation and fortification for nutrient gaps or use of precision fermentation to produce dairy without cows were not discussed. However, it is clear that eliminating dairy would see many nutritional shortfalls and challenges arguably larger than what we currently face with feeding our growing population. Findings from the DELTA Model show at only 7% of global energy provision, dairy contributes 49% calcium, 24% Vitamin B2, 22% Vitamin B12, 18% of EAA, 15% Vitamin A and12% of protein that is produced by the global food system.

Future scenario planning is critical in solving today’s challenges, and in this case investigating extremist views on what a reduced GHG system could look like. Finding a sustainable food system is not as simple as removing a major food source to reduce GHG emissions; the net impact must be considered. Biases aside, this study highlights the importance of considering all aspects of sustainability: environmental, nutritional, and economic, when proposing a change to the global food system. This perspective is supported by the DELTA Model, illustrating the detrimental effect on global nutrient availability of eliminating dairy from the food system.

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Conflict the main contributor to rising food insecurity in Africa

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Food insecurity in Africa is an ongoing concern and has been rising since 2014. However, the causes of insecurity vary from climatic to human. This paper in Nature Food examines the relative contribution of different factors to food shortages.

While it is known that armed conflict, weather events and pests all contribute to food insecurity in Africa, it is not well known how these factors interrelate, and which is most to blame for reducing the availability of food.

The researchers used data from 2009-2018 for the number of people in different African regions requiring emergency food aid, and coupled this with data on droughts, conflict and locust outbreaks over the same period.

It was found that droughts had remained a relatively constant contributor to food insecurity throughout the study period, and locusts had had only a minor impact. In contrast, the researchers found that rising food insecurity could be largely attributed to increases in violent conflict. This was particularly true in regions with higher conflict, such as Nigeria and South Sudan. The study also found that it was livestock producers that were most at risk of food insecurity, compared to crop farming populations and those living along the region’s rivers and coastlines.

Conflict causes food insecurity in a number of ways. It disrupts or destroys food production and supply chain infrastructure, causes migration and impedes the flow of food aid and other external assistance. In combination with droughts, conflict can be devastating for agriculture and take years to recover from. As the authors note, conflicts are far less predictable than drought, and they were unable to establish any relationship between the frequency or magnitude of conflicts and droughts.

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Circularity in the food system

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Research at Wageningen University & Research has been exploring the role animals could play in a circular food system, by converting ‘leftovers’ into valuable food.

Associate Professor Hannah van Zanten, who spoke at the SNi Feed Our Future event in June, leads a team of researchers modelling circular food systems and studying the role that animal production would play. The idea is that farm animals can play a crucial role in sustainable food systems by not consuming human-edible materials, but rather converting forage and ‘leftovers’ (such as crop residues, co-products and unavoidable food waste), into valuable food. In this way, nutrients would be recycled into the food system that would otherwise have been lost.

They report that circularity would also minimize competition for land between feed and food, while still allowing the provision of fertiliser from animal manure. Compared to our current system, it would free up around a quarter of global arable land that is currently used to grow animal feed. This approach would however change the availability of animal-source food for human consumption.

Their modelling work estimated that one third of global protein requirements could be supplied by animals using a circular approach – comparable to current protein provision in the DELTA Model. However, it would require for differing priorities in selecting producing animals due to the reduction in cereals available for feed.

Circularity would also take different forms in different parts of the world. For example, low population densities, high pasture coverage and extensive production systems in NZ mean less food waste and by-products would be available and distributing these to livestock would be challenging. However, in Europe, high population densities coupled with more intensive production would better facilitate implementation of several of the circularity principles.

Moving towards a circular food system requires a food system perspective. It is important to consider the entire food system and the interconnectedness of different food production systems, rather than thinking of different components in isolation.

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DELTA Model® published in Journal of Nutrition

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Results of the SNi DELTA Model® have this week been published in the Journal of Nutrition. The paper details the construction of the model, the scope of its use, and some key results that challenge widely repeated ideas in the food system.

As detailed in the paper, the DELTA Model® is an online tool that allows users to design global food system scenarios (in terms of production, waste and use) and see the outcomes for human nutrition. For example, a user can design a scenario with increased food production and decreased food waste, which the model will then use to calculate the nutrients available to the global population. This value is then compared to the nutrients that the population requires, calculated using demographic data coupled with age and gender specific nutrient requirements.

How does the model work?

DELTA was developed using publicly available datasets from international organisations, complemented with key information from the scientific literature. It takes global food production totals and runs them through a calculation pipeline:

  1. Allocation: food items are allocated to their uses. This includes use as animal feed, processing into other food or non-food commodities, seed for following growing seasons, and non-food use (such as sugar crops for biofuel production). The amount wasted along the supply chain is also deducted.
  2. Consumer use: a substantial amount of food matter is not consumed, either because it is considered non-edible (such as animal bones and vegetable peel), or it is simply thrown away uneaten.
  3. Conversion to nutrients: food composition data are used to convert the total amount of food consumed into a total amount of nutrients consumed. 29 essential nutrients are included.
  4. Bioavailability scaling: specific nutrients are scaled for bioavailability, i.e. the ability of the body to utilise these nutrients when consumed in certain foods.

The total amount of bioavailable nutrients is then compared to the requirements of the global population. This can either be today’s population, or a forecast population in the future, and DELTA considers the demographic makeup of these populations when calculating nutrient requirements, because not all individuals have the same nutrient needs.

What are the results of the model?

In this paper, the DELTA Model® was used to address a number of different questions.

Where are the gaps in our current food production system?

Using 2018 data, it was found that there was sufficient availability of most nutrients to feed the global population. The only exceptions were calcium and Vitamin E. There was even sufficient macronutrients (e.g. protein, energy, fat) to nourish the 2030 population. This demonstrates that the problems of undernutrition present in the world are partly due to the inequitable distribution of food.

What about food waste?

The DELTA Model® found that even completely removing food waste doesn’t solve all our nutritional problems. There still wouldn’t be enough calcium or Vitamin E for the global population. This is because we waste different amounts of different nutrients, so reducing waste has a varied impact on nutrient availability.

Comparison between levels of waste for each nutrient considered by the DELTA Model® in 2018. The bars show total nutrient waste and loss as a percentage of target daily intake. Nutrient waste is dominated by waste of plant foods, and varies greatly between nutrients.

What foods should we be producing in the future?

The DELTA Model® wasn’t designed to be prescriptive, so no optimal food production system is given. Instead, a few example future scenarios are discussed, each of which fails to meet nutritional needs in some way.

Scaling up food supply with the population doesn’t resolve nutrient gaps, it just keeps them from growing any larger.

Removing meat and seafood production to achieve a globally vegetarian diet increases the food available to people due to reduced animal feed demand, but leaves gaps for key nutrients for which these foods are major contributors, such as iron, zinc and Vitamin B-12.

Increases in plant food production can help to feed a growing population, but using this technique alone to meet nutrient requirements may come with an excess intake of energy.

Finally, halving waste by 2050 is an admirable goal, but not the whole answer. Doing so would keep macronutrients above requirement, but would leave many micronutrient deficiencies.

What’s novel about DELTA?

There exist several other models for global nutrition which perform a similar role to DELTA (e.g. GENuS, The Global Nutrient Database, Beal et al.). The key points of difference and novelty in DELTA are:

  • Accessibility: few of the alternative models are openly available for the general public to use to gain a better understanding of global nutrition. Moreover, many of the alternative models use data that is not publicly accessible, making interpretation more challenging.
  • Bioavailability of nutrients: the DELTA Model® takes into account the fact that 100g of a nutrient from one food is not the same as 100g of that nutrient from another food. For example, DELTA scales the availability of protein and the essential amino acids based on protein quality: the ability of the body to obtain and use these nutrients from different sources. The model also scales the iron and zinc requirements of the global population based on the foods available to meet these requirements. Consideration of bioavailability allows for a more realistic comparison between availability and requirement than is possible from considering content alone.
  • Inclusion of upper and lower safe intake levels for nutrients: we all know about recommended daily intakes for nutrients. However, many nutrients have additional reference values, such as for safe lower and upper intake levels. The DELTA Model® displays these in addition to a target intake, to give the user more information about the adequacy of nutrient supply. For example, in several scenarios detailed in the paper, there is sufficient availability of most required nutrients. However, these scenarios also feature energy availability above the safe upper intake level, implying that obtaining the target levels of other nutrients in these scenarios may necessitate excess energy intake.

The future of the DELTA Model®

The current DELTA Model® has a number of limitations for the SNi team to address in the future. For example, the current version considers 29 nutrients, but this does not include all that are essential to good nutrition. Inclusion of essential fatty acids will be a key next step.

Bioavailability is currently only included for some of the nutrients in the model. This will be developed in the future, but is limited by the availability of data for all nutrients from all foods.

Future versions of the model will also need to calculate the environmental impacts of food system scenarios. At present, it is the user’s responsibility to decide whether their scenario is possible from an environmental perspective. We are currently working on land use sub-models, which will allow the user to see the required land necessary for food production in their scenario. Other environmental impacts will follow.

Under justified scrutiny from an environmental sustainability perspective, the global food system needs to change. However, it is essential that the nutritional implications of any change are not forgotten. The DELTA Model® is a tool that allows us to investigate future food system scenarios to see what is possible from a nutrition perspective, to be considered alongside the other aspects of sustainability.

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All content relates to or was reproduced from Smith et al. (2021) Journal of Nutrition

Insects are in!

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While it may seem a rather squeamish topic, edible insects have been found to provide a healthy source of protein for humans. With a low environmental footprint, insect protein looks to be growing as a favourable alternative protein source for the future.

A recent paper in The American Journal of Clinical Nutrition has found that mealworms provide a high-quality protein source that matches that of milk protein. Through the use of isotope labelling, this research found that the nine essential amino acids in mealworm-derived protein had the same performance on digestion, absorption and stimulation of muscle growth as milk protein.

Milk protein is often considered the “gold standard” for protein quality, with plant-based proteins falling in behind due to their often-incomplete profile of amino acids and lower bioavailability. Although a rich nutrient source, milk is often criticised for its environmental footprint due to methane emissions, water use and quality, and agricultural land use change. Insects on the other hand can be reared at scale with minimal environmental impact, and according to the present study can provide a high-quality protein source for the human diet.

At present, the major non-food uses of insects are in animal feed and fertiliser. However, research like this and others (e.g. EFSA’s safety assessment, FAO paper on benefits of insect-based protein) along with significant market value growth indicates future development in this industry for human food is likely. To unlock the potential of edible insect-derived protein, the negative perceptions of eating insects in the Western World would need to be overcome.

This study highlights the promising benefits of mealworm as an environmentally friendly protein source for the human diet. However, milk provides more than just protein. Arguably more important than being a protein source, dairy foods are an important source of micronutrients often difficult to otherwise adequately source from our diets, including Vitamin B2 and B12, calcium and potassium. The use of milk as a comparison to novel protein sources is useful but before any conclusions can be formed around substitution potential, the entire nutrient profile of foods must be considered to determine other benefits exclusive of protein.

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Feed Our Future event to bring science, government and industry together

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.

Social perspectives on the future of livestock

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A recent article in Animal Frontiers identifies the social perspectives on the sustainability of animal-sourced food production, with a view to what this production might look like in the future.

The increasing global population and per capita income is predicted to drive food demand up by around 50%. But it is challenging to predict what role livestock will have in satisfying this demand.

As well as requiring increases in productivity with a reduced environmental footprint, animal-sourced food producers must maintain their “social license to operate” – the acceptance of their practices by consumers. General interest in how animal-sourced foods are produced is rising, and the author contextualises this discussion with some statistics for the US livestock industry.

From an environmental perspective, improvements are being made in reducing the amount of feed, land, water and greenhouse gas emissions of animal-sourced foods due to improved genetics, crop yields and management practices. US beef production reduced its land use footprint per kilo of beef by 33% between 1977 and 2007 and greenhouse gases by 16%. US pork production reduced its feed use per kilo of pork by 67% between 1959 and 2009, and water use by 22%. US milk production has reduced land use, fuel use and greenhouse gas emissions by around 20% each in just the ten years up to 2017.

There is also evidence that further improvements can be made, with wide differences in the footprints of animal-sourced food production even within the same country. Bringing the average closer to best practice should be as much a goal as pushing the boundaries of how small these footprints can become. These improvements must also be communicated to consumers.

The article identifies three key issues that should be prioritised by the animal-sourced food industry when considering its future: accounting for greenhouse gases equitably, with consideration of their differing lifespans; wider use of non-human-edible by-products as animal feed; and greater consideration of animal health and welfare. Each of these priorities will have benefits for the production, environmental sustainability and consumer perceptions of animal-sourced foods.

The author’s final thought is around demonstration and communication of the facts around animal-sourced food production, to ensure than consumer choices are evidence-based.

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Photo by Annie Spratt on Unsplash