Putting sustainable diets into practice
Putting sustainable diets into practice
This article has been published in Food Science & Technology Journal 2016Introduction
A recent report by the World Resources Institute[1] states that the world’s food system faces a great balancing act. By 2050 it has to feed 9.6 billion people in a more sustainable way: without increasing the area of agricultural land, using less natural resources and, very importantly, emitting less greenhouse gases (GHG). In addition, diets should be healthier and adapted to human nutritional needs, preventing both malnutrition and non-communicable diseases, like obesity and cardiovascular disease. The research area of sustainable diets attempts to provide answers on how to meet these challenges.The human impact on climate change illustrates the magnitude of the task ahead. Global greenhouse gas emissions (GHGe) were 49.1 Gigatonnes (Gt) of CO2 equivalents in 2010. By 2050 this needs to be decreased to 21.4 Gt in order to stay below the limit of a 2˚C temperature rise. The emissions that can directly be attributed to the food system are estimated to be 8.7 Gt CO2e, which need to be reduced to 4.4 Gt CO2e by 2050 to meet the target. Since the world’s population is estimated to rise to 9.6 bn by 2050, this would imply that each citizen must reduce his or her emissions by 66%. Other important impacts on the environment caused by the food system are land occupation, water scarcity and eutrophication (surplus of nutrients in water). In this article, we will focus on GHGe as an environmental indicator, for reasons of simplicity. GHGe are also known as the Carbon Footprint (CF) of a product.
Mitigation of GHG emissions by the food system
As a major contributor to global GHGe (20-30%), the food system should play a part in their mitigation.The sustainability of diets can be tackled in three ways:
- Change in diet: eating more healthily with lower environmental impact (consumers)
- Decreasing the impact per unit of food product (agriculture, food companies)
- Making foods more nutritious per unit (agriculture, food companies)
Change in diet
Using the Optimeal® tool to define low-carbon diets, it was concluded that with dietary change, a reduction in GHG emissions and agricultural land use of approximately 70% is feasible, while at the same time assuring that diets still meet nutrient requirements. This is a theoretical result, because these modelling studies identify diets that are very basic and unappealing for the average consumer living in developed countries.Decreasing the impact per unit of product
Decreasing the environmental impact per unit of food product and making foods more nutritious are of clear interest to food and beverage companies. However, methods are required to assess the sustainability performance of foods in a healthy diet. Priorities depend on the context, as dietary needs, dietary habits and the level of development vary between markets.Making foods more nutritious per unit
This could encompass fortification of foods but also making more efficient use of raw materials. Fortification with minerals and synthetic vitamins in, for example, soy drinks or meat replacers, is an environmentally efficient way of making foods more nutritious. Without these additives the product would not be a suitable replacement for dairy or meat.Biofortification could also make foods more nutritious. In plantbased foods this can be achieved by plant breeding (e.g. golden rice) and in animal-based foods by engineering the feed. Another possibility is to make more efficient use of crops. Many foods contain refined ingredients, such as vegetable oils, starch, sugar or isolated proteins. During the refining process essential nutrients from the raw material are often lost for human nutrition and end up in animal feed.
Assessment of current portfolio and new concepts
Facing global sustainability issues and public pressure, it is imperative that companies develop a clear understanding of the strengths and weaknesses in their current product portfolio with respect to environmental impacts and nutrient intake and have identified the weaknesses that contribute most (hotspots) by doing a contribution analysis. Once the priorities are clear, a strategy can be developed to address them. This analysis can also be applied to new product concepts. The following steps are required to assess both the current portfolio and the viability of new concepts in the context of sustainable diets.
1. Identification of nutritional and environmental hotspots
Identification of hotspots can be achieved by a contribution analysis, focusing on key environmental indicators, qualifying nutrients and disqualifying nutrients within national diets. The comprehensiveness of this analysis depends on the availability of data. Although this contribution analysis is meant as an initial exercise to create insight in what matters most, it requires detailed data on food consumption at the level of individual foods. These are available from sources like EFSA’s Comprehensive European Food Consumption Database or NHANES/WWEIA (USA). Each food in the survey needs to be linked to generic or company specific data on environmental impacts and food composition data. The latter is available from public sources like Ciqual (FR), McCance & Widdowson’s (UK), NEVO (NL) or USDA’s National Nutrient Database for Standard Reference (USA). The main obstacle here is the availability of environmental data, since it is quite an investment to perform cradleto- grave Life Cycle Assessments (LCAs) of a large number of foods and beverages covering all relevant environmental impacts. As a starting point the Carbon Footprint (CF) is suitable. LCA data is available on foods covering a large proportion of the diet [2,3].A contribution analysis of qualifying and disqualifying nutrients can focus on national and international priorities. For macronutrients these are are very similar in all developed countries: energy, saturated fat, alcohol, sugar and fiber. Micronutrients of importance to public health differ between countries and sections of the population[4]. In the UK, a large proportion of the population (youths, adults, seniors) is at risk of magnesium, potassium, selenium and vitamin D deficiency, while in France iodine intake too is generally low.
Table 1 Contribution analysis: alcoholic beverages in the diet of UK adults, with priority nutrients and CF
2. Assessing the balance between environmental impact and nutrient density
Innovations go through several phases before they are market ready. At an early stage, new concepts can be assessed on their sustainability performance in a country’s average diet. Key to this analysis is an assessment of the balance between environmental impact and nutrient density (E/N-balance), which can provide valuable input for product development within food and beverage companies. Quite often, this balance is neglected and elimination of certain foods is suggested on the basis of their high environmental impact, without regard for the impact on macro- and micronutrient intake. This can lead to the misconception that the environmental impact of animal-based products is always worse than that of plant-based products, while in reality there is a large grey area between the extremes where they overlap. In this area the nutritive value determines how the balance swings.As a recent paper[5] in this journal pointed out, there is an absence of consensus on the metrics of sustainable diets as well as on methodology integrating both environmental and nutritional dimensions.
However, two recently developed methods offer potential for measuring the sustainability of food products:
Optimeal
with the Optimeal® [6,7] optimisation tool it is possible to test how environmental indicators of the total diet change when more of a food is added to an average national diet, while at the same time keeping the energy intake constant and all macro- and micronutrients within required levels. If the environmental impact reduces with increasing amounts in the diet the E/N balance is favorable and the product can be regarded as having a good sustainability performance. The slope of the plot is an indicator of the E/Nbalance (Figure 1).Nutrient Balance Concept (NBC)
Developed by Nestlé [8,9], this calculates the density of qualifying nutrients, the so-called Nutrient Balance (NB), and the ratio between an environmental indicator and the NB (denominator). A high ratio is an indicator of foods that are a less environmentally efficient source of nutrients.Example: the E/N balance
The use of these two methodologies for product concepts in which both environmental impact and nutrient density varied were compared. The results obtained with both methods were in agreement, which helped to determine the future development strategy. Figure 1 shows the results obtained with the Optimeal method. In separate simulations each of these 5 products (A to E) was added to an average national diet. For A and B the CF of the diet increased significantly more than for C, D and E.A similar ranking was obtained with the NBC method (Figure 2), but the difference between products was more marked. Here, product D gave the lowest E/N balance, indicating that this is probably the most futureproof concept.
Both methods differ in scope: the NBC method focuses on the products, while the Optimeal method takes the whole diet into account. An advantage of the Optimeal method is that there is a clear tipping point in the performance, where a product becomes better than average. Providing data on nutrient composition and environmental impacts is available for each product, both methods can generate results quickly, although the NBC method is more suitable for assessing a large number of concepts. With Optimeal only one simulation can be run at a time. At present it is too early to judge which of the two methods works best in practice and provides more insight.
Figure 1 Optimeal Method: products C, D and E have the best E/N-balance.
Figure 2 E/N Balance determined with the NBC. Product D has the best profile.
Conclusions
Although the approach outlined does not include all metrics for sustainable diets, this study has shown that it is possible to take the first steps towards an assessment of the performance of foods in sustainable diets and solve actual issues arising within product development in the food and beverage industry. Firstly a contribution analysis can provide insight into the strengths and weaknesses within a company’s current product portfolio. Once these are clear, a strategy can be developed to address the hotspots. Secondly, an analysis of the E/N-balance can help in assessing whether new food concepts are future-proof.References
- Searchinger T & et al. (2013) Creating a Sustainable Food Future - World Resources Report 2013–14: Interim Findings. Washington, USA:
- Biesbroek S, Bueno-de-Mesquita BH, Peeters PHM, et al. (2014) Reducing our environmental footprint and improving our health: greenhouse gas emission and land use of usual diet and mortality in EPIC-NL: a prospective cohort study. Environ. Health 13, 27.
- Temme EHM, Toxopeus IB, Kramer GFH, et al. (2014) Greenhouse gas emission of diets in the Netherlands and associations with food , energy and macronutrient intakes. Public Health Nutr. 7.
- Mensink GBM, Fletcher R, Gurinovic M, et al. (2013) Mapping low intake of micronutrients across Europe. Br. J. Nutr. 110, 755–73.
- Dötsch-Klerk M, Mela DJ & Kearney M (2015) Sustainable diets. Food Sci. Technol. 29, 32–35.
- Tyszler M, Kramer G & Blonk H (2014) Comparing apples with oranges: on the functional equivalence of food products for comparative LCAs. Int. J. Life Cycle Assess. 19, 1482–1487.
- Tyszler M, Kramer G & Blonk H (2015) Just eating healthier is not enough: studying the environmental impact of different diet scenarios for Dutch women (31–50 years old) by linear programming. Int. J. Life Cycle Assess.
- Fern EB, Watzke H, Barclay D V., et al. (2015) The Nutrient Balance Concept: A New Quality Metric for Composite Meals and Diets. PLoS One 10, e0130491.
- Espinoza-orias N, Roulin A, Watzke H, et al. (2014) Connecting the dots: assessing sustainable nutrition at Nestlé. In 9th Int. Conf. LCA Food San Fr. USA 8-10 Oct. 2014.
More information
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