An energy- and nutrient-corrected functional unit to compare LCAs of diets

Mixed diets can meet nutrient requirements with lower carbon footprints

Achieving sustainable dietary change is essential for safeguarding human and environmental health. However, dietary recommendations based on broad food groups may not accurately reflect real-world realities because individuals select and consume dishes with multiple food items influenced by diverse context-specific factors. Therefore, here we explored the sustainability trade-offs of dietary choices at the dish level through an optimization modeling approach tested in Japan. We estimated the nutritional quality, price, and carbon footprint of major Japanese dishes and examined 16 dietary scenarios to identify options that meet the nutritional requirements and minimize carbon footprint. Overall, mixed diets contain more combinations of dishes that meet nutritional requirements with lower carbon footprints compared to more restrictive dietary scenarios. We argue that the approach developed here enables a better understanding of dietary trade-offs, complements existing methods, and helps identify sustainable diets by offering nuanced information at the national and sub-national levels.

Circularity of new composites from recycled high density polyethylene and leather waste for automotive bumpers. Testing performance and environmental impact

New composite materials (suitable for automotive bumpers), composed of recycled high-density polyethylene (rHDPE) and leather buffing dust waste (BF) ranging from 20 to 50 wt%, were produced and investigated for mechanical properties. Optimal mechanical performance was achieved with composites containing 30 % wt BF. The environmental performance of automotive bumper production from both virgin and recycled HDPE reinforced with 30 % wt BF (HDPE-BF, rHDPE-BF) composites was compared to that of conventional polypropylene (PP) by performing a cradle to gate life cycle assessment. A component-based approach, instead of a comprehensive LCA assessment for the entire car was adopted using various functional units (FU) such as mass (FU1), volume (FU2), and volume of raw material fulfilling a specific impact strength requirement (FU3), thus enriching the paper with methodological discussions. The rHDPE-BF system provided better environmental performance compared to the virgin PP system, when considering both mass and volume-related functional units, mainly due to the avoidance of virgin polymer production. Even with the inclusion of the use phase in FU2 and a slightly higher density (+1.7 %) of composites than PP-based bumpers, the rHDPE system still provides better environmental performance (10 % less impact). The sensitivity analysis highlighted the significance of car type and final density of the bumper on the impact results. Finally, when using FU3, due to its higher impact strength, HDPE-BF system is clearly the best environmental alternative (50 % less impact) followed by rHDPE-BF system. In all cases, rising the content of recycled materials in the bumpers increases its circularity. The paper illustrates the importance of selecting a suitable functional unit, based on a specific application (i.e., automotive bumpers), to evaluate the environmental impact of new composite materials in comparison to traditional options. Expanding the assessment to encompass multiple functions provides a more accurate portrayal of reality but also introduces greater result uncertainty.

Linking LCA literature with circular economy value creation: A review on beverage packaging

The ever-increasing volume of packaging waste is widely recognised as a key global environmental challenge. Packaging is thus a central concern for advocates and analysts of circular economy (CEc), who often apply the life cycle assessment (LCA) methodology when measuring the environmental impacts of products and packaging. We undertook a systematic literature review as a research method, and in-depth analysis to ascertain the extent to which the new CEc paradigm has been integrated in LCA methodology applied to beverage packaging and reported in scientific papers. Carefully developed search strings returned 866 articles relevant to our enquiry from the databases of SCOPUS and Web of Science. Applying our selected eligibility criteria, we extracted a subset of 51 articles for in-depth analysis. The analysed literature shows the links between the quality of packaging material for recycling and the profoundness of the LCA studies. The paper provides the following set of recommendations for enhancing the future practice in development of the scientific LCAs for beverage packaging: (i) taking all direct and indirect factors into account when assessing the refillable beverage packaging system and conducting break-even analysis in order to achieve impartial comparative assessments of single-use and refillable systems; (ii) developing proxies in cases when actual data is lacking with which to model the recycling scenarios for exported secondary materials and hence improving the accuracy of recycling rate assessments in LCA models; (iii) improving the definition of the LCA function by introducing multiple loops of the packaging material and assessing qualitative changes in the material resulting from the multiple-recycling process. Thus improved practice of LCAs could better inform and improve the design of new packaging strategies aimed at prolonging the life of packaging materials in the technosphere, equally fulfilling the principles of the CEc.

Introducing a Degrowth Approach to the Circular Economy Policies of Food Production, and Food Loss and Waste Management: Towards a Circular Bioeconomy

There is a growing debate surrounding the contradiction between an unremitting increase in the use of resources and the search for environmental sustainability. Therefore, the concept of sustainable degrowth is emerging aiming to introduce in our societies new social values and new policies, capable of satisfying human requirements whilst reducing environmental impacts and consumption of resources. In this framework, circular economy strategies for food production and food loss and waste management systems, following the Sustainable Development Goals agenda, are being developed based on a search for circularity, but without setting limits to the continual increase in environmental impacts and resource use. This work presents a methodology for determining the percentage of degrowth needed in any food supply chain, by analyzing four scenarios in a life cycle assessment approach over time between 2020 and 2040. Results for the Spanish case study suggested a degrowth need of 26.8% in 2015 and 58.9% in 2040 in order to achieve compliance with the Paris Agreement targets, highlighting the reduction of meat and fish and seafood consumption as the most useful path.

An explorative assessment of environmental and nutritional benefits of introducing low-carbon meals to Barcelona schools

Shifting to plant-based and low-carbon diets is a key measure for climate change mitigation. In this regard, national and local governments are setting goals and actions to tackle this issue. The municipality of Barcelona has set an intervention for the academic year 2020-21: introducing low-carbon meals in public schools. This study assesses the environmental and nutritional benefits of this intervention by applying the Life Cycle Assessment (LCA) methodology, with an energy and nutritional functional unit; and combined it with the Water-Energy-Food (WEF) nexus approach, by considering three WEF resources-based impacts (Blue Water Footprint (BWF), Primary Energy Demand (PED) and Land Use (LU)) and the Global Warming Potential (GWP). The transition to a low-carbon meal would reduce between 46 and 60% the environmental impacts. These benefits could even be higher when extra interventions within the school boundaries are applied. More research in behavioural change is needed in order to evaluate both: the acceptance of the new menus by scholars and the adaptation of the school kitchen staff to the new menu. Finally, it is suggested to monitor the environmental and nutritional changes of the introduction of low-carbon meals within the school menus in an integrated way.

Environmental and nutritional impacts of dietary changes in Spain during the COVID-19 lockdown

The COVID lockdown has affected food purchases and eating habits. In this regard, this short communication assesses the nutritional and environmental impacts of these changes during the COVID lockdown in Spain, by applying Life Cycle Assessment and an energy- and nutrient-corrected functional unit. Three environmental impacts were studied (Global Warming Potential, Blue Water Footprint and Land Use) and a total of seven weekly diet scenarios were designed: two pre-COVID diets for March and April in 2019 (MAR19, APR19), one COVID diet (COVID) and two alternative diets, one based on the National Dietary Guidelines (NDG) and another one on the Planetary Health Diet (PHD). Results show that the COVID diet had larger energy intake and lower nutritional quality, as well as higher environmental impacts (between 30 and 36%) than the pre-COVID eating patterns. Further research is needed to account for food affordability within this assessment, as well as to analyze how eating patterns will evolve after the COVID lockdown. Finally, the definition of short guidelines for sustainable food behaviors for future possible lockdowns is suggested, as well as the introduction of sustainable indicators within NDGs.

Multi-Objective Optimization of Nutritional, Environmental and Economic Aspects of Diets Applied to the Spanish Context

Current food consumption patterns must be revised in order to improve their sustainability. The nutritional, environmental, and economic consequences of these dietary patterns must be taken into consideration when diet guidelines are proposed. This study applied a systematic optimization methodology to define sustainable dietary patterns complying with nutritional, environmental, and economic issues. The methodology was based on a multi-objective optimization model that considered a distance-to-target approach. Although the three simultaneous objectives (maximal nutritional contribution, minimal greenhouse gas emissions, and minimal costs) could be divergent, the proposed model identified the optimal intake of each food product to achieve the maximal level of nutritional, environmental, and economic diets. This model was applied to six different eating patterns within the Spanish context: one based on current food consumption and five alternative diets. The results revealed that dietary patterns with improved nutritional profiles and reduced environmental impacts could be defined without additional costs just by increasing the consumption of vegetables, fruits, and legumes, while reducing the intake of meat and fish.

Food waste management during the COVID-19 outbreak: a holistic climate, economic and nutritional approach

Improving the food supply chain efficiency has been identified as an essential means to enhance food security, while reducing pressure on natural resources. Adequate food loss and waste (FLW) management has been proposed as an approach to meet these objectives. The main hypothesis of this study is to consider that the "strong fluctuations and short-term changes" on eating habits may have major consequences on potential FLW generation and management, as well as on GHG emissions, all taking into account the nutritional and the economic cost. Due to the exceptional lockdown measures imposed by the Spanish government, as a consequence of the emerging coronavirus disease, COVID-19, food production and consumption systems have undergone significant changes, which must be properly studied in order to propose strategies from the lessons learned. Taking Spain as a case study, the methodological approach included a deep analysis of the inputs and outputs of the Spanish food basket, the supply chain by means of a Material Flow Analysis, as well as an economic and comprehensive nutritional assessment, all under a life cycle thinking approach. The results reveal that during the first weeks of the COVID-19 lockdown, there was no significant adjustment in overall FLW generation, but a partial reallocation from extra-domestic consumption to households occurred (12% increase in household FLW). Moreover, the economic impact (+11%), GHG emissions (+10%), and the nutritional content (-8%) complete the multivariable impact profile that the COVID-19 outbreak had on FLW generation and management. Accordingly, this study once again highlights that measures aimed at reducing FLW, particularly in the household sector, are critical to make better use of food surpluses and FLW prevention and control, allowing us to confront future unforeseen scenarios.

Adherence to the Mediterranean Diet and Environmental Impact of the Diet on Primary School Children Living in Parma (Italy)

The key role of diet in both human health and environmental sustainability is well known. However, there is a lack of studies investigating the environmental impact of children's dietary behavior. The aim of this observational study was to investigate the dietary environmental impact in a sample of primary school children living in Parma (Italy, n = 172, 8-10 years), in relation to their adherence to the Mediterranean diet (MD). Children completed a 3-day food record in both winter and spring. Dietary records were processed to obtain: (i) adherence to the MD and (ii) mean daily carbon and ecological footprints. Adherence to the MD was similar in winter and spring, with almost half of the participants showing a medium MD score. Carbon and ecological footprints were higher during winter, and the main dietary contributors were red and processed meat for both indexes. A small positive correlation was observed between adherence to the MD and total carbon and ecological footprints. This study provided the first analysis of the relationship between adherence to the MD and environmental impact of primary school children. Further research is needed to better investigate the environmental impact of primary school children's diet and the possible relationship between the MD and environmental sustainability.

The Environmental Impact of the Athlete's Plate Nutrition Education Tool

Periodized nutrition is necessary to optimize training and enhance performance through the season. The Athlete's Plate (AP) is a nutrition education tool developed to teach athletes how to design their plates depending on training load (e.g., volume × intensity), from easy (E), moderate (M) to hard (H). The AP was validated, confirming its recommendations according to international sports nutrition guidelines. However, the AP had significantly higher protein content than recommended (up to 2.9 ± 0.5 g·kg-1·d-1; p < 0.001 for H male). The aim of this study was to quantify the environmental impact (EnvI) of the AP and to evaluate the influence of meal type, training load, sex and registered dietitian (RD). The nutritional contents of 216 APs created by 12 sport RDs were evaluated using Computrition Software (Hospitality Suite, v. 18.1, Chatsworth, CA, USA). The EnvI of the AP was analyzed by life cycle assessment (LCA) expressed by the total amount of food on the AP, kg, and kcal, according to the Swiss Agricultural Life Cycle Assessment (SALCA) methodology. Higher EnvI is directly associated with higher training load when the total amount of food on the plate is considered for E (5.7 ± 2.9 kg CO2 eq/day); M (6.4 ± 1.5 kg CO2 eq/day); and H (8.0 ± 2.1 kg CO2 eq/day). Global warming potential, exergy and eutrophication are driven by animal protein and mainly beef, while ecotoxicity is influenced by vegetable content on the AP. The EnvI is influenced by the amount of food, training load and sex. This study is the first to report the degree of EnvI in sports nutrition. These results not only raise the need for sustainability education in sports nutrition in general, but also the urgency to modify the AP nutrition education tool to ensure sports nutrition recommendations are met, while not compromising the environment.

Is the reusable tableware the best option? Analysis of the aviation catering sector with a life cycle approach

Annually, around 7.7 billion passengers travel by plane. The menus served during the flight are quite similar between different airlines and are composed of the food itself, packaging (paper envelopes, film, etc.) and tableware (mainly trays, plates, glasses, cups and cutlery). In 2016, 1522 tonnes of tourist class menus were served in Iberia aircrafts landing at Madrid Barajas airport in Spain. From this amount, 51% by weight was packaging and tableware, and the remaining 49% food. As changes in the food has little room for maneuver, since the same amount would be delivered regardless how it is served, this study focus on the possibilities of packaging and tableware to reduce GHG emissions. The assessment has been done using life cycle assessment methodology (LCA) in order to identify the hotspots along the whole life cycle of packaging and tableware items. The case study chosen was the catering service of Iberia, the national airline of Spain. The functional unit used was "the service of 1,000 tourist class menus on Iberia flights that landed in Madrid in 2016". The results show that the impacts of reusable and single use items take place at different stages of their life cycles. For reusable ones, 76% of the impact is produced during the flight phase, meanwhile, for single use ones, 53% of the impact comes from the production stage. Variables such as material, weight and the number of reuses can greatly influence greenhouse gas (GHG) emissions. From the results of the analysis some eco-design strategies has been proposed and analysed. The paper reveals that the lighter single-use packaging and tableware for airline catering are less harmful under a life cycle perspective become.

Main environmental impacts associated with production and consumption of milk and yogurt in Serbia - Monte Carlo approach

Dairy consumption studies or life cycle assessment of dairy products have been in research focus for several years providing useful information. However, limited number of studies confronted the two types of data in order to analyze environmental impacts associated with consumers. The objective of this research was to calculate these impacts, namely global warming potential (GWP), ozone depletion potential (ODP), cumulative energy demand (CED), acidification potential (AP) and eutrophication potential (EP) related to the consumption of milk and yogurt in Serbia. In the present paper, life cycle assessment study was performed using data from nine dairy farms and ten dairy plants. The system boundary applied is 'cradle-to-retail' comprising data from cow farms, raw milk transportation, processing and transportation of dairy products. In parallel, a survey on the consumption of milk and yogurt was conducted analyzing responses from 957 dairy product consumers. It was found that milk production is responsible for the emission of 1.511 kg CO2_e/kg of milk, 7.720 MJ_e/kg, 0.1363 mg R11_e/kg, 12.164 g SO_2e/kg and 17.825 g PO_4e/kg while the results for yogurt are slightly higher 1.672 kg CO2_e/kg, 7.804 7.720 MJ_e/kg, 0.1369 mg R11_e/kg, 12.238 g SO_2e/kg and 17.609 g PO_4e/kg. Further calculations also revealed that weekly emission of GWP, CED, ODP, AP and EP associated with an average consumer of milk and/or yogurt in Serbia was estimated at values of 2.254 kg CO_2e/week, 10.926 MJ_e/week, 0.19261 mg R11_e/week, 17.191 g SO_2e/week and 24.363 g PO_4e/week. These results may be of interest to all actors in the dairy chain giving them a wider perspective of sustainable consumption of dairy products.