Contribution of different life cycle stages to the greenhouse gas emissions associated with three balanced dietary patterns

Rethinking food loss and waste to promote sustainable resource use and climate change mitigation in agri-food systems: A review

The sustainable agri-food system is an important sector recognized for promoting the United Nations' Sustainable Development Goals on food security, resource conservation and climate change mitigation. However, the increasing food loss and waste (FLW) along the supply chains has continued to hinder these goals. This study evaluates the trend of FLW research from 1975 to 2022 and how it promotes the achievement of resource and environmental sustainability in agri-food systems. The salient research themes and hotspots that are of interest to researchers were identified. Bibliometric and network analyses were carried out on scholarly research articles from the Scopus database using bibliometrix and VOSviewer. Furthermore, the content analysis was conducted on the selected highly influential articles containing relevant data to understand the role of FLW in promoting sustainable agri-food systems. The results showed disaggregate and unbalanced research distribution on the impacts of FLW among the countries, with China and the United States having the highest contributions. The identified major research themes relating to sustainable agri-food systems are food waste and sustainable systems, food waste management and food waste impact assessment. Moreover, the circular economy was found to be a relatively new approach being explored in agri-food systems to promote FLW reduction and ensure sustainability of resource use. This study highlights the critical role of the impact of FLW in addressing the grand challenge of food security, resource use efficiency and environmental sustainability.

Towards interactive explanation-based nutrition virtual coaching systems

The awareness about healthy lifestyles is increasing, opening to personalized intelligent health coaching applications. A demand for more than mere suggestions and mechanistic interactions has driven attention to nutrition virtual coaching systems (NVC) as a bridge between human-machine interaction and recommender, informative, persuasive, and argumentation systems. NVC can rely on data-driven opaque mechanisms. Therefore, it is crucial to enable NVC to explain their doing (i.e., engaging the user in discussions (via arguments) about dietary solutions/alternatives). By doing so, transparency, user acceptance, and engagement are expected to be boosted. This study focuses on NVC agents generating personalized food recommendations based on user-specific factors such as allergies, eating habits, lifestyles, and ingredient preferences. In particular, we propose a user-agent negotiation process entailing run-time feedback mechanisms to react to both recommendations and related explanations. Lastly, the study presents the findings obtained by the experiments conducted with multi-background participants to evaluate the acceptability and effectiveness of the proposed system. The results indicate that most participants value the opportunity to provide feedback and receive explanations for recommendations. Additionally, the users are fond of receiving information tailored to their needs. Furthermore, our interactive recommendation system performed better than the corresponding traditional recommendation system in terms of effectiveness regarding the number of agreements and rounds.

Interventions to Strengthen Environmental Sustainability of School Food Systems: Narrative Scoping Review

School food systems play a role in the wider food system, but there is a scarcity of literature exploring interventions that aim to improve the environmental sustainability of school food systems. The present review aimed to understand and describe the types of interventions that have previously been explored to strengthen the sustainability of school food systems along with their impact. We applied a scoping review methodology guided by Arksey and O'Malley, which included a review of the online database Scopus and the grey literature. Information relating to intervention design, study population, evaluation method and impact were extracted. In total, 6016 records were screened for eligibility, 24 of which were eligible for inclusion. The most common types of interventions were school lunch menus designed to be more sustainable; school food waste reduction; sustainable food system education using school gardens; and dietary interventions with added environmental components. This review highlights a range of interventions which could positively influence the environmental sustainability of school food systems. Further research is needed to explore the effectiveness of such interventions.

The Environmental Sustainability of Plant-Based Dietary Patterns: A Scoping Review

BACKGROUND

A large part of the existential threat associated with climate change is the result of current human feeding patterns. Over the last decade, research evaluating the diet-related environmental impacts of plant-based diets has emerged, and a synthesis of the available data is now due.

OBJECTIVES

The objectives of the study were as follows: 1) to compile and summarize the literature on diet-related environmental impacts of plant-based dietary patterns; 2) to assess the nature of the data on impacts of plant-based dietary patterns on both environmental parameters and health (e.g., if land use is reduced for a particular diet, is cancer risk also reduced?); and 3) to determine where sufficient data exist for meta-analyses, in addition to identifying gaps within the literature.

METHODS

Global peer-reviewed studies on the environmental impacts of plant-based diets were searched in Ovid MEDLINE, EMBASE, and Web of Science. After removing duplicates, the screening identified 1553 records. After 2 stages of independent review by 2 reviewers, 65 records met the inclusion criteria and were eligible to be used in synthesis.

RESULTS

Evidence suggests that plant-based diets may offer lower greenhouse gas emissions (GHGEs), land use, and biodiversity loss than offered by standard diets; however, the impact on water and energy use may depend on the types of plant-based foods consumed. Further, the studies were consistent in demonstrating that plant-based dietary patterns that reduce diet-related mortality also promote environmental sustainability.

CONCLUSIONS

Overall, there was agreement across the studies regarding the impact of plant-based dietary patterns on GHGE, land used, and biodiversity loss despite varied plant-based diets assessed.

An integrated literature review on sustainable food supply chains: Exploring research themes and future directions

The sustainable food supply chain (SFSC) is a research area of global significance. The increasing number of research articles in SFSC justifies this. With 80% of publications in SFSC coming up in the last 7 years, this field is expanding and diversifying at a rapid rate. The research on sustainable food supply chain (SFSC) covers a wide variety of areas and has a wide range of research themes in FSC. To facilitate the theoretical understanding of SFSC, we have conducted a review of the literature on SFSC. With the aim to define prominent research themes in SFSC, we follow an integrated review approach of structured literature review (SLR), bibliometric analysis, and thematic analysis. Bibliometric analysis was conducted using the vosviewer software version 1.6.16. The thematic analysis identified- "Waste management", "SC sustainability and impact assessment", "Decision support", "Operations management and optimization", "Food quality and safety", "Sustainable business models", "Innovation and technological solution", "SC strategy", and "Social sustainability" as the key emergent themes. We discuss the conceptual and theoretical basis of each of these themes. "SC sustainability and impact assessment" is identified as the most dominant theme in SFSC. Innovation and technological solution is an emerging theme with many new publications related to disruptive technologies coming up. Research in collaboration and decision theory-based approaches is important to enable sustainability in FSC. Quantifying waste streams, identifying hotspots are important future directions of research in SFSCM. Circular economy, AFSC, and the use of advanced technologies to enable circularity and sustainability also have great scope. The review aims to help researchers and academicians understand the boundaries and domain of SFSC and the future scope of these themes about how they can enhance the sustainability in SFSC.

Life Cycle Environmental Impacts and Health Effects of Protein-Rich Food as Meat Alternatives: A Review

The food sector is responsible for a considerable impact on the environment in most environmental contexts: the food supply chain causes greenhouse gas emissions, water consumption, reduction in cultivable land, and other environmental impacts. Thus, a change in food supply is required to reduce the environmental impacts caused by the food supply chain and to meet the increasing demand for sufficient and qualitative nutrition. Large herds of livestock are inappropriate to achieve these goals due to the relevant impact of meat supply chain on the environment, e.g., the land used to grow feed for animals is eight times more than that for human nutrition. The search for meat alternatives, especially for the intake of critical nutrients such as protein, is a consequent step. In the above context, this paper summarizes the health aspects of protein-rich food alternatives to meat and carries out a literature review on the life-cycle environmental impacts of this alternative food.

Effects of different Danish food consumption patterns on Water ScarcityFootprint

Food production and consumption have been recognized as a major source of environmental impacts. To ensure food security and a sustainable food system, dietary changes have been identified as one of the valuable strategies to reduce impacts on the environment while promoting human health. The vast majority of scientific literature has been focused on the effects of food consumption on climate change while neglecting to assess the degree of water scarcity impacts due to water consumption embodied in food. The research paper investigates the nexus between food consumption and impacts on water consumption adding important findings to a more recent growing body of studies estimating the water footprint (WF) of different dietary scenarios. This study uses the Water Footprint Network methodology and the AWARE (Available Water REmaining) characterization model to assess both the WF and the blue WSF (water scarcity footprint), respectively, of four Danish diets: standard, carnivore, vegetarian and vegan. In order to make them comparable, a total intake of 2000 kcal person^-1 day^-1 was set as energetic reference for all the diet scenarios considered. Using detailed trade and production data of agri-foods, we were able to assess the location of primary production and consequently to reveal countries mainly affected by water scarcity associated with import to satisfy Danish diets consumption. We found that while the vegan scenario scored the best environmental profile requiring 1489 L/cap/day calculated with the volumetric WF approach, it has the largest potential impacts on blue WSF of 10,477 L_H20-eq/cap/day. This study has shown that more than 90% of impacts on water consumption occur outside the national borders, as a consequence of large quantities of fruits and nuts imported by countries already threatened by high water scarcity conditions such as USA and Mediterranean regions. This methodological approach may be used to compare environmental performances of recommended dietary guidelines and to assess impact scenarios of new trade policies, protecting local water scarcity levels.

Differences in Environmental Impact between Plant-Based Alternatives to Dairy and Dairy Products: A Systematic Literature Review

A large body of research suggests a more plant-based diet, including a switch to plant-based alternatives to dairy, is needed for lowering human-induced climate change as well as land and water use. With the help of a systematic literature review, we analyzed data from 21 peer-reviewed articles about the differences in emissions and resources used between various plant-based alternatives to dairy and dairy products. Emissions included were greenhouse gases, acidifying, eutrophicating, and ozone-depleting substances, and resource use included water, energy, and land. The results are presented as the quotients of the ratios of plant-based alternatives to dairy and dairy products. The comparison shows that the plant-based dairy alternatives have lower, or much lower, impacts in almost all cases, with two exceptions: water use for almond drinks (several studies) and emissions of ozone-depleting substances for margarine (one study). There is a lack of data concerning impacts other than greenhouse gas emissions for plant-based cheese alternatives; and in general, emissions of greenhouse gases are more highly covered than other impacts. In the quest for a swift transition to a low carbon economy, however, there is already enough evidence to proceed with a dietary change involving switching dairy products to plant-based alternatives.

Exploring adults' motives for food choice of sustainable diet components: a qualitative study in Tehran Metropolis

BACKGROUND

Todays, due to the impact of human food choices on increasing greenhouse gas emissions, water consumption and environmental degradation, there is a new approach about changing the pattern of food production and consumption, including sustainable food and nutrition system related to consumption. This study aimed to explore the components of a sustainable diet among the factors that affect people's food choices.

METHODS

This qualitative study was carried out using an in-depth interview with 33 individuals aged 30-64 years old living in different areas of Tehran. Data collection, data analysis and theoretical conceptualization were performed simultaneously. MAXQDA 10 software was used for managing and organizing the data.

RESULTS

In this paper, the findings are categorized according to the key components of a sustainable diet in five themes: "Health and Nutrition", "Food and Agriculture Security", "Environment and Ecosystems", "Markets, food trade and production chains", "social, cultural, and policy factors" were categorized. Meanwhile, the components of the "Health and Nutrition" domain had the highest contribution and the components of the two domains "food and agriculture" and "environment and ecosystems" had the lowest role based on the participants' perception in this study.

CONCLUSION

Considering to the low importance of the components of a sustainable diet in food choices of the community, promoting the individual awareness of sustainable diet components, clarifying the importance of food choices in creating environmental impacts and leading the national macro policies in the field food and nutrition toward sustainable diet goals are essential.

Evaluation of the influence on water consumption and water scarcity of different healthy diet scenarios

A deep understanding of the water-food nexus it is of a paramount importance as an avenue for sustainable development. Water forms the foundation for food production and a sustainable use of this resource is essential to guarantee the long-term productivity and to build resilient capacity in food and agricultural systems. Here we present methodological challenges regarding different water footprint (WF) methods applied to different dietary scenarios. The volumetric WF of three theoretical but realistic dietary patterns has been quantified (Omnivorous(O), Vegetarian(V) and Vegan(VG)), by means of the Water Footprint Network methodology. Moreover, the AWARE methodology is applied to assess potential impacts of water use trough the Water Scarcity Footprint (WSF). Diets are set to integrate and consider different drivers for food consumption encompassing the social value of the Mediterranean diet, healthy diet recommendations, food preferences of Italian consumers and the trade dimension of foodstuffs. In terms of volumetric WF, the O diet is the most water intensive one accounting for 2800 L/capita/day. A shift from an O to a V and VG diets allows to reduce the volumetric WF respectively 10% and 14%. Green water consumption accounts for the largest share (85%) in all three scenarios. Considering the WSF, V healthy diet is similar to the VG resulting in 11,069 and 11,130 L H₂Oeq/capita/day respectively, whereas the O diet resulted in 11,932 L H₂Oeq/capita/day. A sensitivity analysis was performed by changing each food category, one at a time, to its maximum and minimum value, in order to evaluate the significance of changes in the volumetric WF and WSF as well as the variables that mostly contribute to them. Results show that the volumetric WF associated with V and VG diets consumption overlay the O diet in respectively 53.5% and 35.7% of runs, while overlapping is improved comparing WSFs results. In this case, the WSFs of V and VG diets overlay the O diet in 83.5% of runs, suggesting that the alternative dietary scenarios would have little effect on the overall WSF and that the results are particularly sensitive to the different countries of importation. Results demonstrate the need to consider both volumetric WF and WSF with particular attention to trade analysis in order to support the development of new policies with the aim to foster sustainable consumption patterns, while preserving water resources.

Life cycle assessment applied to waste management in Italy: A mini-review of characteristics and methodological perspectives for local assessment

Life cycle assessment (LCA) and related tools are commonly used to evaluate the potential environmental impacts of waste treatment scenarios. This manuscript presents a mini-review of studies published over the last 10 years in Italy and aims to investigate how life cycle thinking tools are applied to assess the environmental sustainability of local-level waste policies. Results reveal that different waste flows, technologies and policies have been investigated independently and in varying detail. Review suggests that boundary selection significantly affects LCA results; integration of different waste systems is therefore crucial to avoid spatial or temporal shifts of environmental impacts. Moreover, the description of methodological characteristics, limitations and transversal aspects of Italian waste management studies allows various stakeholders to assess the reliability of past and future research for waste policy planning and rebound effects prevention. This review also highlights the need to define minimum requirements of transparency and ease of reporting of the studies to private and public stakeholders. Finally, the paper investigates whether using both the organisational LCA and the life cycle sustainability approach for the overall waste management process may be useful to develop a standard method to address multi-functionalities and multiple sites.

The potential benefits of dietary shift in China: Synergies among acceptability, health, and environmental sustainability

The transition to a healthier diet recommended by national dietary guidelines in China may not achieve sufficient environmental benefits. This study assesses China's potential of transforming into a sustainable diet and the trade-offs among reducing food-related environmental impacts, improving nutritional quality and respecting eating habits. We used multi-objective optimization to build optimized scenarios, with the lowest environmental footprint and greatest acceptability (i.e., with the minimum departure from the currently observed diet) as optimization goals, and adequate macro- and micronutrient intake levels as constraints. In doing so, we assessed the actual benefits and synergies of reducing carbon footprint (CF), water footprint (WF), and ecological footprint (EF) and improving health and respecting dietary acceptance under the corresponding scenarios. The results show that CF, WF and EF can be reduced by up to 19%, 15% and 30% respectively, while satisfying nutritional constraints and achieving the minimum deviation from the current food combination. The greatest synergistic benefits for CF, WF and EF are achieved when the minimum CF is the optimization goal; the maximum synergistic benefits for the environment, health and acceptability are achieved when the CF is reduced by 10%. Our findings identify the trade-offs and synergies dietary changes considering nutritional benefits, environmental sustainability and acceptability, and reveal the challenges and opportunities for achieving such synergies.

Could the economic crisis explain the reduction in the carbon footprint of food? Evidence from Spain in the last decade

Dietary patterns are influenced by numerous external factors such as cultural taste and customs, nutritional and economic aspects and lifestyle and consumer preferences. Otherwise, food also causes a great impact on the environment and there can be a large difference between choosing certain foodstuffs, such as plant or animal-based ones. The key for an environmentally friendly and healthy diet is the high consumption of plant-based products, low amounts of animal-origin foodstuffs and limited quantity of refined grains, processed food and added sugars. Nevertheless, adherence to it has been decreasing over the years due to the adoption of a more westernized consumption pattern. Thus, the main goal of this study is to monitor the food consumption pattern at household level during a period of 10 years (2008-2017), selecting Spain as case study. Both the impacts that foodstuffs included in the food basket cause in the environment, and the socio-economic variables that influence the consumer choice are considered. Results show a generalized decrease of the carbon footprint over the years. However, it does not always mean an approach to a healthier diet, considering that in this case it decreases both the consumption of those foods with a greater environmental footprint as those essential for a balanced diet with low ecological impact. Additionally, there is also an increase in the consumption of processed food, which further distances the dietary pattern from the recommendations, what can be more pronounced for the most vulnerable population groups, with less purchasing power to access healthy food.

Tracking the environmental footprints of institutional restaurant service in nursery schools

When dietary habits are analyzed in the framework of school catering services, nutritional indicators are essential criteria in the definition of menus, but attention should also be paid to the associated environmental impacts. It is especially relevant to assess food patterns in nursery schools when consumption habits are most strongly implemented, and they must be healthy and sustainable. With the aim of evaluating the main environmental indicators: Carbon and water footprints (CF and WF), ten menus consisting of lunch and afternoon snack were evaluated, which comprise a wide range of food categories (fruits and vegetables, starch-based products, milk and milk products, non-dairy sources of protein, and others). The CF of the menus varied considerably according to their composition, with beef-rich menus having the worst profile (up to 2.24 kg CO₂/menu and 0.39 kg CO₂/100 kcal). Regarding the WF, meals rich on animal-based products also entailed water implications and mainly associated with the consumption of beef. Green WF and blue WF are responsible for 88% of the contributions to this indicator, on average. The WF indicator reaches up to 1271 L·menu^-1 and 223 L/100 kcal for a menu containing beef meat. This study confirms the effect on CF and WF from animal-based products, specifically beef meat and dairy products. The findings of the study can be useful to make recommendations not only to consumers on reducing the environmental impacts from food production and consumption, but also to design balanced menus with better environmental scores based on the combination of low and high footprint food products, always providing the necessary energy and nutrients, an unquestionable issue in toddlers and pre-school children whose need to follow balanced and healthy diets, being meat an important foodstuff.

Dietary recommendations in Spain -affordability and environmental sustainability?

Global food demand is increasing due to population growth and dietary transitions, resulting from rising incomes, are associated with increased prevalence of non-communicable diseases. Improving the sustainability of the food sector is also critical for achieving the Sustainable Development Goals. This study assesses for the first time the greenhouse gases emissions (Carbon Footprint - CF), the water footprint (WF) and the cost of three omnivorous diets recommended in Spain due to their health benefits: the Mediterranean diet (MD), the Southern European Atlantic diet (SEAD) and the Spanish dietary guidelines (NAOS). Analysis was conducted using standard Life Cycle Assessment and WF methods together with current Spanish food price data. The dietary energy recommendation of the SEAD is greater than that of MD and NAOS (11 and 15% respectively), and SEAD also has greater animal source food content than the other two diets. SEAD has a concomitantly higher CF, WF and cost scores in comparison with MD (+30%, +23% and +21% respectively) and NAOS (+15%, +9% and +21% respectively). Adjusting recommendations to meet the suggested Spanish adult dietary energy of 2228 kcal.capita-1.day-1 changed the environmental profiles of the diets and the NAOS has the highest environmental impact. However, the isocaloric diets had approximately the same cost. Analysis of the WF of the diets identified the major contribution of precipitation (the green WF) to the overall WF (88% of the total) and the significant contribution of animal-source foods to dietary WF. Regardless of the dietary scenario, better scores were identified for the Spanish recommendations analysed than those reported for other healthy diets identified in Europe. Differences in the recommended intake levels of certain food groups, cooking techniques and the origin of food products are behind these results. Environmental indicators should be considered alongside nutrition and health metrics when defining national dietary guidelines. Supporting citizens to follow healthy and environmentally-friendly dietary recommendations through, among other things, information campaigns and nutritional education programmes is essential. It is recommended the incorporation not only of health, but also of environmental indicators of these dietary options in the national dietary guidelines, as well as implementation of information campaigns and nutritional education programs among citizens to promote their adhesion since balanced dietary habits rich on plant-based products and low on animal-based ones involve multiple health and environmental benefits.

Dietary recommendations in Spain -affordability and environmental sustainability?

Global food demand is increasing due to population growth and dietary transitions, resulting from rising incomes, are associated with increased prevalence of non-communicable diseases. Improving the sustainability of the food sector is also critical for achieving the Sustainable Development Goals. This study assesses for the first time the greenhouse gases emissions (Carbon Footprint - CF), the water footprint (WF) and the cost of three omnivorous diets recommended in Spain due to their health benefits: the Mediterranean diet (MD), the Southern European Atlantic diet (SEAD) and the Spanish dietary guidelines (NAOS). Analysis was conducted using standard Life Cycle Assessment and WF methods together with current Spanish food price data. The dietary energy recommendation of the SEAD is greater than that of MD and NAOS (11 and 15% respectively), and SEAD also has greater animal source food content than the other two diets. SEAD has a concomitantly higher CF, WF and cost scores in comparison with MD (+30%, +23% and +21% respectively) and NAOS (+15%, +9% and +21% respectively). Adjusting recommendations to meet the suggested Spanish adult dietary energy of 2228 kcal.capita^-1.day^-1 changed the environmental profiles of the diets and the NAOS has the highest environmental impact. However, the isocaloric diets had approximately the same cost. Analysis of the WF of the diets identified the major contribution of precipitation (the green WF) to the overall WF (88% of the total) and the significant contribution of animal-source foods to dietary WF. Regardless of the dietary scenario, better scores were identified for the Spanish recommendations analysed than those reported for other healthy diets identified in Europe. Differences in the recommended intake levels of certain food groups, cooking techniques and the origin of food products are behind these results. Environmental indicators should be considered alongside nutrition and health metrics when defining national dietary guidelines. Supporting citizens to follow healthy and environmentally-friendly dietary recommendations through, among other things, information campaigns and nutritional education programmes is essential. It is recommended the incorporation not only of health, but also of environmental indicators of these dietary options in the national dietary guidelines, as well as implementation of information campaigns and nutritional education programs among citizens to promote their adhesion since balanced dietary habits rich on plant-based products and low on animal-based ones involve multiple health and environmental benefits.

The Links between Human Diets and Health and Climate Outcomes in the World's Macro-Regions during the Last 50 Years

Globally, traditional food security fears have been supplemented by concerns about food system sustainability that link current agricultural production practices to damages of environmental ecosystems and the world's climate, thus threatening the natural resource base of future generations. This paper aims at creating a better understanding of the evolution of diet sustainability from 1961 to 2013. Data from the Food and Agriculture Organization of the United Nations were used to investigate the situation for the world as a whole as well as for its macro-regions Africa, Asia, the Americas, Europe and Oceania. We define diet sustainability by (a) the share of daily per capita calorie intake derived from vegetable/plant products and (b) the variety of vegetable/plant products consumed, measured by the Simpson diversity index. Moreover, total calorie consumption is considered. Then the correlations between diet sustainability and (a) macro-regional life expectancy rates and (b) food system greenhouse gas emissions are calculated. The results show that diet sustainability has not changed much during the last 50 years. Moreover, the nexus between diets and health and climate outcomes is not fully evident at the macro-regional level. Therefore, Malthus 2.0, i.e., scientific food pessimism, should be avoided. In particular, the limitations of dietary contributions to human and planetary health ought to be more widely acknowledged.

Which Diet Has the Least Environmental Impact on Our Planet? A Systematic Review of Vegan, Vegetarian and Omnivorous Diets

The food that we consume has a large impact on our environment. The impact varies significantly between different diets. The aim of this systematic review is to address the question: Which diet has the least environmental impact on our planet? A comparison of a vegan, vegetarian and omnivorous diets. This systematic review is based on 16 studies and 18 reviews. The included studies were selected by focusing directly on environmental impacts of human diets. Four electronic bibliographic databases, PubMed, Medline, Scopus and Web of Science were used to conduct a systematic literature search based on fixed inclusion and exclusion criteria. The durations of the studies ranged from 7 days to 27 years. Most were carried out in the US or Europe. Results from our review suggest that the vegan diet is the optimal diet for the environment because, out of all the compared diets, its production results in the lowest level of GHG emissions. Additionally, the reviewed studies indicate the possibility of achieving the same environmental impact as that of the vegan diet, without excluding the meat and dairy food groups, but rather, by reducing them substantially.

Assessing the Carbon Emission Driven by the Consumption of Carbohydrate-Rich Foods: The Case of China

Background: Carbohydrate-rich (CR) foods are essential parts of the Chinese diet. However, CR foods are often given less attention than animal-based foods. The objectives of this study were to analyze the carbon emissions caused by CR foods and to generate sustainable diets with low climate impact and adequate nutrients. Methods: Twelve common CR food consumption records from 4857 individuals were analyzed using K-means clustering algorithms. Furthermore, linear programming was used to generate optimized diets. Results: Total carbon emissions by CR foods was 683.38g CO2eq per day per capita, accounting for an annual total of 341.9Mt CO2eq. All individuals were ultimately divided into eight clusters, and none of the popular clusters were low carbon or nutrient sufficient. Optimized diets could reduce about 40% of carbon emissions compared to the average current diet. However, significant structural differences exist between the current diet and optimized diets. Conclusions: To reduce carbon emissions from the food chain, CR foods should be a research focus. Current Chinese diets need a big change to achieve positive environmental and health goals. The reduction of rice and wheat-based foods and an increase of bean foods were the focus of structural dietary change in CR food consumption.