Waste and losses in the global food system

NickS on 17 June 2021

This Thought for Food article examines the loss of nutrients as a result of food waste. Not all foods are wasted to the same extent, and thus neither are all nutrients. Aggregate numbers for global waste or waste reduction targets mask these important variations.

When considering the impact of changes in the food system, we need to consider the supply of nutrients, as well as the supply of foods. The primary role of the food system is to provide nutrients – in the form of foods – to meet the needs of the global population.

Distinction should be made between food losses and food waste. Losses are the decrease in edible mass along the supply chain prior to retail, and waste the decrease that occurs at the retail and consumer end of the chain. Read More

When demonstrating the impact of food loss and food waste, we should consider the decreases in available nutrients.

When we lose or waste foods containing nutrients that are in abundant supply, this is less critical from a human wellbeing point of view than the loss or waste of foods rich in undersupplied nutrients.

Ways of improving the future food system could include:

  • reducing loss and waste (and potentially lowering production) where we have excess nutrient supply
  • reducing loss and waste (and potentially increasing production) where there are nutrient shortages

So where are the nutrient shortages?

From a macronutrient perspective, current estimates are that nearly 690 million people have insufficient protein and/or energy intakes. However, micro-nutrient deficiencies (hidden hunger) are also an enormous problem: globally, anaemia (iron deficiency) is estimated to impact 43% of 0-5 year olds and 38% of pregnant women; up to 1.8 billion people may have insufficient iodine intake; and 17% of the global population is at risk of zinc deficiency.

The DELTA Model has been created to help people explore future food production scenarios. It uses data on food production, losses, wastes and end uses, coupled with food composition, nutrient bioavailability, population forecasts and nutrient requirements to determine whether a future food system scenario can meet the nutrient needs of the global population. Modelling the food system shows that globally, with equal distribution, we have enough macro-nutrients for all, even carrying current production levels through to feed the 2030 population.

For protein – often cited as a nutrient we need to produce more of to satisfy a growing global demand – there is already enough protein available globally to provide the target intake for the expected 2050 population based on current nutritional guidelines, if it were equitably distributed.

This may seem surprising, but a challenge in discussing the future of food is in separating the nutrition we need, and the nutrition we might want or prefer. Protein is a good example of this. Statements that we “need to expand production by 70%” by 2050 are based on consumer demand rather than requirement. The DELTA Model exposes the differences between demand for specific nutrients such as protein and population requirements.

However, the global story differs for the micronutrients. We are already limited on total supply of Calcium and Vitamin E and will also be limited on Iron, Potassium, Vitamin A and Zinc by 2030 unless changes to the food system are made. That is, even if distributed equally, there is not enough of these nutrients to meet everyone’s needs.

When we look at the distribution of nutrient supply at a country level the picture is worse. The variation in nutrient supply in 2015 shows that a significant proportion of the global population had insufficient access to Calcium, Vitamin E, Iron, Potassium, Zinc, Vitamin A, Riboflavin, Vitamin B12, Fibre, Folate, and Vitamin C.

Relative nutrient supply distribution at a country level in 2015.  All values are normalised to the target intake with the coloured bar showing the global average supply and the error bars showing the range in country level supply from the 10th to the 90th percentile of the global population.

Waste varies with food type, which affects the supply of nutrients in different ways.

Let’s consider a simplified food supply chain: On Farm -> Supply Chain -> Retail -> Consumer

  • On Farm losses are challenging to quantify, as these may include crops or parts of crops not harvested or not used for human food. These quantities are often not recorded either. In many farming systems, waste materials on farm are used to provide food for animals with almost 30% of the global livestock ration coming from crop residues, by-products and coproducts.
  • Once food commodities leave the farm, losses occur along the supply chains that connect farms with retail, including as part of processing into other products. With more expensive commodities there are strong economic drivers to reduce losses through supply chain infrastructure. For less valuable commodities this may not be the case. Well-developed supply chains seek to recover valuable nutrients from by-products and “wastes” by processing into additional foods, animal feeds, or for other uses.
  • At the consumer end of the supply chain, food may be discarded at retail or in-home for its appearance, age, or various other reasons. Consumer waste is generally greater in high income nations where there is the luxury of choice. Individual consumers or households often lack the resources and the incentives to repurpose food waste and inedible material.
Per-capita food waste by country income bracket expressed as Wasted Daily Diets – the number of additional person days of nutrition wasted based on the first limiting nutrient. Data from Chen et al. 2020. 

Across the supply chain economic drivers mean we waste less of what is expensive, which – combined with the perishability of many fruits and vegetables – means food loss and waste is dominated by plant material. Over 20% of fruits, nuts, and vegetables, and their associated nutrients are lost or wasted after leaving the farm gate. Losses of animal products are 7-10%, and losses of more stable plant commodities (e.g. pulses and sugar) are up to 8%. This means that there is less potential to increase the supply of nutrients that are mainly found in animal sourced foods by reducing loss and waste, compared with nutrients common in plant foods. For example, an 50% reduction in all food loss and waste would result in a 16% increase in Vitamin C supply, but only a 6% increase in Vitamin B12.

Overconsumption is a form of waste

The other aspect of waste that needs to be considered is overconsumption. Nutrients consumed in excess of requirements are either excreted in bodily wastes, or in some cases – as with excess food energy intake – accumulated within the body. Once a certain level of supply has been achieved, further intake gives no further benefit to the individual and is thus a form of nutrient or food waste. When we look to the future, reducing overconsumption waste may have a significant impact on global nutrition.

Taking the previous example of Vitamin C, the range in 2015 nutrient supply at a country level was from around 66% of the daily requirement, to more than 2.8 times the target. For Vitamin B12 – sourced almost exclusively from animal foods – the 2015 availability varied from 40% to 1.75 times the target. Reduced waste and more equitable distribution of foods would increase the availability of nutrients to the populations currently below the target.

When considering the question of what to do about food waste, we should also think about the nutrient waste that occurs as part of this. Waste of nutrient rich foods has a greater impact on our ability to nourish populations that waste of nutrient poor foods. Waste occurs at all stages of the supply chain, and there are many forms of consumer waste – including excess intake. Quantifying and addressing how and where we waste important nutrients is a promising route to reducing nutrient deficiencies.

This Thought for Food was written by the SNi team in collaboration with Prof Thom Huppertz and Prof Wayne Martindale.

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

NickS on 8 June 2021

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.

GMO crops in the global food system

NickS on 28 January 2021

Genetically modified organisms (GMO) are already major contributors to the global food system since their commercial introduction in the 1990s. For example, over 90% of US corn and soy acreage is planted with GMO seeds. Despite this, the use of GMO is still controversial, with many individuals against their use and many authorities strictly regulating their production and consumption. Here, the arguments for and against GMO use in crop production are presented. 

GMO are defined as organisms, and products thereof, that are produced through techniques in which the genetic material has been altered in a way that does not occur naturally by mating and/or natural recombination. 

The process in which GMO are created differs depending on the degree of modification required but generally, a desirable trait is identified in one organism that could be of benefit in another. The trait is studied and, if possible, the gene(s) responsible for the trait are isolated. These genes are then introduced to the target organism, either via bacterial or viral infection, where the microorganism carries the target gene into the organism for uptake, or by bombarding the organism with particles coated in the target gene. 

The outcome of the process is a GMO that expresses the desired trait isolated from the original organism. 

Advantages of GMO  

The ability to transfer desirable traits between distantly related crops that cannot be interbred has obvious benefits. Examples of GMO use include the ability to increase photosynthetic rate, develop crops that are drought-tolerant with increased yields, and produce crops with disease resistance, such as blight-resistant potatoes. 

Moreover, crops can be developed that have greater nutritional value than conventional varieties. There exists a long list of such biofortified crops, including cassava with increased zinc, iron, protein and vitamin A content, high lysine maize, high provitamin A rice, and corn with increased provitamin A and folate. These crops are of particular value in global regions where nutrient deficiencies are a high priority public health issue. 

One widely used GMO is Bt-maize. This crop takes its name from Bacillus thuringiensis, the bacterium that donated to the maize plant the trait of producing an insecticidal toxin. Thus, Bt-maize is more resistant to pest insects than conventional maize, leading to higher yields and reduced pesticide use. As a result, 82% of the crop grown in the US in 2020 was the Bt variety. 

Disadvantages of GMO  

The arguments against GMO are largely based on health and environmental risks. The approval process for GMO is nationally administered, so differs between countries. Largely, these processes are more rigorous than for conventional foods and assess both the health and environmental risks of the GMO. 

The World Health Organisation states that no negative health consequences of approved GMO have been shown to date. However, concerns and risks do exist. One health concern raised is the possibility of allergenicity being unintentionally transferred between organisms. An example of this was when early GMO researchers, hoping to increase methionine content, found that the main allergen from Brazil nuts retained its allergenicity after transfer into a GMO soybean. As a result, the GMO soybean was never released commercially and allergenicity is now an important consideration when selecting donor crops. 

From an environmental perspective, there is the possibility that the GMO crop itself, or the introduced gene via cross-breeding or gene transfer, could escape the farmed environment and become a pest. The implications of this would depend entirely on the nature of the GMO crop; for example, transfer of a herbicide resistance gene to a non-target organism could lead to difficulties in controlling its growth. Alternatively, GMO crops could outcompete other plants due to the introduced trait, resulting in decreased biodiversity with unknown downstream implications. While the risk of these unintended consequences is low, they should be considered in the design and management of GMO. 

Finally, some express the opinion that GMO are morally wrong, as they involve too great an interference with living organisms. Such a decision can only be weighed by the individual but will likely mean that a proportion of the population will continue to avoid foods containing GMO products. 

This avoidance is challenging given the ubiquity of GMO products in many foods and by the difficulty for a consumer in identifying GMO foods. Different authorities take different stances on GMO labelling. For example, GMO are not specifically labelled in the US, rather foods that contain ‘bioengineered’ ingredients must be labelled as such. However, specific food labelling for certain types of GMO is on the horizon. The EU has stricter rules, with a requirement for GMO ingredients to be listed on food packaging. However, major food retailers have previously been forced to change their GMO policies due to the increasing “risk of finding GM material in non-GM food”. 

Conclusion 

GMO are widespread in the global food system, but not equally distributed.  

Moreover, regulation of GMO production varies and is not always clear and explicit. There are countries, like the US, where GMO crop production is widespread. Contrastingly, 19 member countries of the European Union have previously voted to either partially or fully ban the use of GMO. In New Zealand, no GMO crops are commercially grown. These variations in use and acceptance will certainly limit investment and development of future GMO. However, there is the opportunity for countries that have a GMO-free stance to use this status to market their products at a premium. 

GMO crops generally result in decreased pesticide use, coupled with increased yields and profitability. Moreover, there are those that believe that GMO will be necessary to adequately nourish a growing population and to adapt production to changing climates. The risks of GMO largely relate to unintended and uncertain consequences that must certainly be properly managed if GMO use and development is to increase. 

This Thought for Food was written by Cody Garton, a summer intern from Pūhoro STEM academy

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Peas please

NickS on 19 January 2021

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Food Foundation in the UK are gaining traction with their ‘Peas Please: Making a pledge for more veg’ initiative, the results of which were recently described in Nutrition Bulletin. 

Despite a historically growing UK market for fruit, which has increased by around 50% since 1970, vegetable purchasing was seen to slowly decline over the same period. The common perceptions of vegetables as boring or not that tasty was likely not helped by minimal publicity, with only 1.2% of the UK food advertising spend used to market vegetables. On top of this, there are questions around the environmental impacts of the average UK shopping basket, and ample evidence that field-grown vegetables have small environmental footprints. 

Most of the UK public do not meet dietary guidelines for vegetables, particularly those with lower incomes. On top of low purchase rates, 40% of purchased vegetables in the UK are wasted at home. This matches the global trends of food waste shown by the DELTA Model, where most of the nutrient waste is from plant-sourced foods. Altogether, the nutritional and health implications of low vegetable intake due to consumer choice and waste needs to be tackled. 

The ‘Peas Please’ initiative aims to make eating vegetables more healthy, affordable, sustainable and pleasurable. Organisations, such as supermarkets and restaurants, pledge to follow these directives, in the hope of changing the way the country treats vegetables. Their website features ways in which individuals, communities and businesses can engage with the initiative and forge better relationships with vegetables. 

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65 kg of food waste per person per year

NickS on 17 November 2020

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Research investigating nutrient losses via food waste give an intuitive understanding of the implications of food waste.

Food waste across 151 countries was assessed, using indicators for nutrient loss across 25 different nutrients. Globally, it was found that 65 kg of food was wasted per person per year, which when compared to nutrient requirements is the equivalent of 18 daily diets. In other words, the food that is wasted annually by one person could meet their nutritional requirements for 18 days.   

This study considered the whole composition of food, including micro-nutrients, rather than taking a single-dimensional approach such as weight, calories or protein only. It found that high-income nations wasted six times the weight of food wasted by low-income nations, and that plant-sourced foods were wasted more than animal-sourced foods. Cereals, fruits and vegetables were the major contributors to wasted nutrients. This matches the results of the DELTA Model, which shows that nutrients wasted both in-home and along the supply chain are predominantly plant foods.  

Although many assumptions and the extrapolation of data was necessary to generate the global values, the study does give a more intuitive understanding of the impact of food waste, and what it means in terms of global nutrient provision and environmental impacts. 

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Canteen food waste can be more than food consumed

NickS on 29 September 2020

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A case study of a US school canteen found that 54% of all food purchased was uneaten.

Globally, the UN estimates that around one third of food is wasted somewhere along the path from on-farm production through to in the home. This represents a huge challenge to creating a sustainable food system, and waste reduction is a key target for improving sustainability. However, a recent case study shows that certain eating environments including different age groups may contribute more to food waste than others. 

The researchers followed the path of food in a US school canteen from purchase, through service and consumption to what was left on the plate after lunchtime. This plate waste accounted for 37% of the total food purchased, with preparation losses taking the total wasted up to 54%. This plate waste value was much higher than the 2-39% found in US households, suggesting differing behaviour in the canteen environment. 

The difference may also be because the canteen users were predominantly children. Food waste decreased with age in this study: elementary and middle school children wasted around half of the food on their plates, whereas high school children and staff members wasted around 30%. Perhaps unsurprisingly, fruit and vegetables were the most wasted food groups. 

The researchers conclude that service changes (such as reducing the number of buffet choices) would be the easiest changes to implement, but not the most effective. The most effective strategies would target the food choices made by the canteen users and understanding why waste is greater at school than at home. 

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