Assessment of diet-related GHG emissions using the environmental hourglass approach for the Mediterranean and new Nordic diets

The Two Dimensions of Nutrition for the Planet: Environment and Health

PURPOSE OF REVIEW

Protecting the planet is protecting the future. Food production systems are among the most important human activities threatening planetary health. Diet, food systems, the environment, and health are interconnected. Accordingly, this review aims to assess the effects of nutrition on the planet and the relationship between some types of diets defined as sustainable and the planet and human health.

RECENT FINDINGS

Many diets have been proposed to protect the planet and human health, but there is no consensus on which diet is best. It should not be forgotten that planetary health diets, plant-based diets, and vegetarian/vegan diets can reduce environmental pressure. Still, they cannot have the same effect in every country, and these diets may have different effects depending on the differences in the countries' income level, nutritional culture, and food systems. Moreover, it should not be overlooked that these diets may cause difficulties in terms of adaptation, cause deficiencies in some nutrients, and may not be suitable for all segments of society. Sustainable diets such as the Mediterranean and New Nordic, as well as Dietary Approaches to Stop Hypertension, are more flexible and acceptable. Instead of a globally recommended reference diet to protect the planet and human health, each country can analyze its food systems and choose the most appropriate food production methods and sustainable diet style to reduce environmental burden, improve health, and create policies accordingly, which can help achieve sustainable goals faster.

Greater adherence to the Mediterranean diet pattern in the United States is associated with sustainability trade-offs

BACKGROUND

The Mediterranean diet pattern has been consistently associated with health benefits but less is known about the association with environmental and economic sustainability in the United States (US). This information is needed to support sustainable policy agendas and provide consumers with evidence-based information needed to make informed food choices. This study fills this research gap by evaluating the environmental sustainability and diet cost associated with adherence to the Mediterranean diet pattern in the US.

METHODS

Dietary data from the National Health and Nutrition Examination Survey (2011-2018, n = 17,079) were merged with data on environmental impacts (greenhouse gas emissions, cumulative energy demand, water scarcity footprint), agricultural resource demand (land, fertilizer nutrients, and pesticides), and food prices from multiple publicly available databases. The Mediterranean Diet Score was used to evaluate adherence to the Mediterranean diet pattern. Multivariable linear regression models were used to evaluate the association between adherence to the Mediterranean diet pattern and environmental impacts, agricultural resource demand, and diet cost. Sensitivity analyses were used to evaluate adjustment of loss and waste and food-away-from-home prices.

RESULTS

Greater adherence to the Mediterranean diet pattern was associated with lower greenhouse gas emissions (p < 0.001), land use (p < 0.001), fertilizer nutrient use (p < 0.001), and pesticide use (p < 0.001), higher water scarcity footprint (p < 0.001) and diet cost (p < 0.001), and no change in cumulative energy demand (p = 0.147). These changes were driven primarily by reduced intake of animal-sourced foods such as beef dishes, meat sandwiches, and dairy, as well as decreased intake of refined carbohydrate foods such as refined grain dishes and soft drinks.

CONCLUSIONS

This nationally representative study demonstrates that greater adherence to the Mediterranean diet pattern is associated with sustainability trade-offs. These findings have implications for the development of sustainable dietary guidelines and clinical practice guidelines that can be used to inform consumer food choices.

Environmental and Health Sustainability of the Mediterranean Diet: A Systematic Review

The Mediterranean diet (MD) has been shown to be a healthy dietary pattern (DP), and lately it is increasingly being studied as a sustainable DP. The aim of this study is to analyze whether the MD is a sustainable and healthy DP accounting for its carbon footprint, water footprint (WF), land use (LU), and/or energy use, based on the existing scientific literature. We conducted a systematic review following PRISMA guidelines and registered in PROSPERO (CRD42022309916). We included 35 studies: 25 modeling studies, 7 cross-sectional, and 3 longitudinal. Twenty-four studies compared the sustainability of the MD with that of other DPs; 21 assessed the sustainability of the MD compared with dietary consumption data; and 9 evaluated the MD's adherence and its environmental impacts. A total of 29 studies analyzed the carbon footprint, 11 the LU, 20 the WF, and 7 the energy use of the MD. Six articles assessed the health aspect of the diet apart from the environmental impact. The MD showed high nutritional quality, ranging between 122 and 178 points on the health score and between 13.51 and 90.6 points on the nutrient-rich food index. Using the results for environmental footprints in the same measurement units, we were able to quantitatively compare the most frequently assessed diets with MD. When compared with other diets, 91% of the studies referred to the MD as a sustainable DP, and most of the articles in which its adherence was assessed obtained an inverse correlation with the environmental footprints. Environmental footprints of the MD ranged from 1.03 to 5.08 kg CO2-eq/person-day for greenhouse gas emissions, 257.2-2735.2 L/person-day for WF, and 4-14.8 m2/person-day and 2.85-3.32 m2∗year/d for LU. In summary, the available evidence suggests that, in general, the MD is a sustainable and healthy DP, which aligns with planetary health.

Adherence to the Mediterranean diet is associated with sustainable nutrition and environmental footprints on higher educated individuals

Introduction: This study aimed to investigate the relationship between Med-Diet adherence with sustainable nutrition and environmental footprints in academicians. Methods: The study involved 153 academicians aged 23-64 working in a university in Turkey. Data were collected through a questionnaire including socio-demographic characteristics, anthropometric measurements, Mediterranean Diet Adherence Scale (MEDAS) and Sustainable and Healthy Eating Behaviours Scale (SHEBS). Carbon and water footprints were calculated. Results: All sub-scales of SHEBS were higher in individuals who adhered to Med-Diet than those who did not (p<0.05). The carbon and water footprints of individuals with high adherence to the Med-Diet were lower than those of no adherence (p<0.05). Each 1-point increase in MEDAS score was associated with a 1-point increase in SHEBS score, a 0.15 CO2 eq/kg and a 0.001 m3/year decrease in the amount of carbon and water footprint of food. Conclusion: Higher adherence to the Med-Diet was associated with higher sustainable nutrition behaviours, and lower environmental footprints.

Relationship between adherence to the Mediterranean diet, sustainable and healthy eating behaviors, and awareness of reducing the ecological footprint

This study evaluated the relationship between adherence to the Mediterranean diet (MD), sustainable and healthy eating behaviors, and awareness of reducing the ecological footprint. It was conducted with 1333 adults (38.2% male, 61.8% female, mean age 24.2 ± 7.5 years). The questionnaire included socio-demographic characteristics, anthropometric measurements, the Awareness Scale for Reducing Ecological Footprint (ASREF), the Sustainable and Healthy Eating (SHE) Behaviors Scale, and Mediterranean Diet Adherence Scale (MEDAS). 40.2% of the participants adhered to the MD (≥7 scores). Obese individuals' total scores on MEDAS, SHE Behaviors Scale, and ASREF were the lowest (p < 0.05). In regression analysis, education duration, SHE Behaviors Scale total score, and BMI affected the ASREF score (p < 0.05). The education duration, SHE Behaviors Scale scores, and ASREF scores were higher in those in MD-adherence group (p < 0.05). In conclusion, adherence to the MD was associated with higher sustainable and healthy eating behaviors and higher awareness of ecological footprint reduction.

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.

Animal- and Plant-Based Protein Sources: A Scoping Review of Human Health Outcomes and Environmental Impact

Dietary proteins are indispensable to human nutrition. In addition to their tissue-building function, they affect body composition and regulate various metabolic pathways, as well as satiety and immune system activity. Protein use can be examined from a quantitative or qualitative viewpoint. In this scoping review, we compare animal- and plant-based protein sources in terms of their effects on human health and the environment. We conclude that the consumption of vegetable protein sources is associated with better health outcomes overall (namely, on the cardiovascular system) than animal-based product use. The healthier outcomes of vegetable protein sources dovetail with their lower environmental impact, which must be considered when designing an optimal diet. Indeed, the health of the planet cannot be disjointed from the health of the human being. Future research will clarify the mechanisms of action underlying the health effects of plant-based protein sources when compared with animal sources, fostering better agronomic practices and influencing public health in a direction that will benefit both the planet and its inhabitants.

Sustainability Dimensions of the Mediterranean Diet: A Systematic Review of the Indicators Used and Its Results

The concern about sustainability is growing and the Mediterranean diet has been extensively identified as a promising model, with benefits for human and environmental health. This systematic review aims to identify and describe the indicators that have been used to evaluate the sustainability of the Mediterranean diet and the results from their application. A methodology using PRISMA guidelines was followed, and searches were performed in Web of Science, PubMed, Scopus, and GreenFile. A total of 32 studies assessing the sustainability of the Mediterranean diet were identified. Twenty-five of these studies quantified the environmental impact, 7 studies evaluated the nutritional quality, and 12 studies assessed the daily cost of this dietary pattern. A total of 33 distinct indicators were identified, of which 10 were used to assess the environmental dimension (mainly, carbon, water, and ecological footprint), 8 were used to assess the nutritional dimension (mainly Health score and Nutrient Rich Food Index), 1 was used to assess the economic dimension (dietary cost), and 8 used combined indicators. The remaining 6 indicators for the assessment of sociocultural dimension were only identified in 1 study but were not measured. The Mediterranean diet had a lower environmental impact than Western diets and showed a carbon footprint between 0.9 and 6.88 kg CO2/d per capita, a water footprint between 600 and 5280 m3/d per capita, and an ecological footprint between 2.8 and 53.42 m2/d per capita. With regard to the nutritional dimension, the Mediterranean diet had a high nutritional quality and obtained 122 points on the Health score and ranged between 12.95 and 90.6 points on the Nutrient Rich Food Index. The cost of the Mediterranean diet is similar to other diets and varied between 3.33 and 14.42€/d per capita. These findings show that no uniformity in assessing the MDiet's sustainability exists.

Incorporation of novel foods in European diets can reduce global warming potential, water use and land use by over 80

Global food systems face the challenge of providing healthy and adequate nutrition through sustainable means, which is exacerbated by climate change and increasing protein demand by the world's growing population. Recent advances in novel food production technologies demonstrate potential solutions for improving the sustainability of food systems. Yet, diet-level comparisons are lacking and are needed to fully understand the environmental impacts of incorporating novel foods in diets. Here we estimate the possible reductions in global warming potential, water use and land use by replacing animal-source foods with novel or plant-based foods in European diets. Using a linear programming model, we optimized omnivore, vegan and novel food diets for minimum environmental impacts with nutrition and feasible consumption constraints. Replacing animal-source foods in current diets with novel foods reduced all environmental impacts by over 80% and still met nutrition and feasible consumption constraints.

Driving commitment to sustainable food policies within the framework of American and European dietary guidelines

Diet and nutrition are essential factors in promoting good health throughout life. Their role as determinants of chronic non-communicable diseases is widely recognized. Additionally, the demand for food involves relevant environmental burdens that have to be taken into account on the way to achieving the Sustainable Development Goals. As an important part of nutrition policy, food-based dietary guidelines (FBDGs) have been revised. The key question is: Are environmental considerations being incorporated into them? To address this issue, we modeled and compared both the main environmental indicators in terms of carbon footprint (CF) and water footprint (WF), and nutritional quality (according to the Nutrient Rich Diet index, NRD9.3 and a health gain score) of dietary guidelines from Northern and Southern Europe and America. Particularly, the FBDGs compared were Dutch Dietary Guidelines (DDG), New Nordic Diet (NND), Spanish Strategy for Nutrition, Physical Activity and Obesity Prevention (NAOS), Mediterranean Diet (MD), Italian Dietary Guidelines (IDG) and American Dietary Guidelines (DGA). The IDG and MD offered the best profiles from a climate change perspective (2.04 and 2.21 kgCO₂eq·day^-1). Overall, DGA had the highest CF (2.98 kgCO₂eq·day^-1). WF presented greater fluctuations, not only due to daily-recommended amounts, but also because of different climate conditions and production systems of the reference countries. Hence, WF ranged from 1760 L·person^-1·day^-1 in IDG to 3181 L·person^-1·day^-1 in NAOS. Finally, the nutritional value of MD, which had the highest NRD9.3 (477) and health gain score (178), has been demonstrated when the comparison was made with DDG, the one with the lowest health gain score (97) and DGA, the worst in terms of NRD9.3 (391). To go ahead of the FBDGs that bet on all dimensions of sustainability, multi-criteria analysis is needed. Nutrition and environmental performance are not the only aspects of the problem; economy and sociocultural variables should be considered.

Assessment of the Methodology That Is Used to Determine the Nutritional Sustainability of the Mediterranean Diet-A Scoping Review

Mediterranean diet (MedDiet) is often used as an example of a sustainable diet that promotes a sustainable food system. MedDiet presents low environmental impacts, is characterized by high sociocultural food values, allows for positive local economic returns, and presents major health and nutrition benefits. Previous studies have not systematically examined the methodological assessment of MedDiet nutritional sustainability. In our study, we review the methodological assessment of nutritional sustainability, filling a crucial gap in the literature that can inform the state of the art regarding the cross-disciplinary assessment of MedDiet nutritional sustainability. Through a systematic search on PubMed and Scopus, we identified 28 studies, published between 2013 and 2021, that dealt with the MedDiet nutritional sustainability. Studies that assessed the sustainability of MedDiet based on dietary consumption data, studies that explored the MedDiet sustainability resorting to dietary scenarios, and studies with a mixed approach (dietary consumption and dietary scenarios) and proposals of methodological approaches to assess the MedDiet nutritional sustainability were summarized. We identified 24 studies exploring the dimensions of nutritional sustainability of the MedDiet, and 4 proposing the methodological approaches to assess the MedDiet nutritional sustainability or the sustainability of MedDiet typical agro-foods. From the 24 studies exploring the sustainability of MedDiet, none fully addressed the complexity of the four dimensions of nutritional sustainability (environmental, economic, socio-cultural, and health-nutrition). One of the methodological proposals to assess the MedDiet nutritional sustainability contemplated on the four dimensions of nutritional sustainability, as well as one of the methodological proposals to assess the sustainability of typical agro-foods of MedDiet. Environmental sustainability was the most well-studied dimension, while no study focuses on the socio-cultural dimension of sustainability. Our study reviewed for the first time the assessment of nutritional sustainability of MedDiet. To the best of our knowledge, no research has been made assessing MedDiet in all the dimensions of the complex concept, that is nutritional sustainability. Integrating health and nutrition, environmental, economic, and socio-cultural considerations across scales and contexts can offer a more complete understanding of the opportunities and barriers to achieving nutritional sustainability not only in MedDiet but also in other dietary patterns and food products.

Towards a More Sustainable Nutrition: Complementary Feeding and Early Taste Experiences as a Basis for Future Food Choices

The concept of sustainable nutrition considers different fields: from human health to environmental, economic and socio-cultural aspects. Currently, in Europe, the diets that reflect the assumptions of the sustainable diet are the Mediterranean Diet and the New Nordic Diet. They both encourage the consumption of vegetable, organic and minimally processed foods, as well as regional, seasonal and Fair-Trade products, reducing the ecological impact of the production chain. These eating habits could be established starting from the prenatal period and from infancy during the complementary feeding stage, aiding children to accept of a more variable diet in terms of flavor, taste and texture. In particular, the positive parental role model is an effective method for improving a child’s diet and behaviors. Two healthy plates representing a sustainable diet in early infancy, at 6 and 24 months, are here proposed, in line with the “Planetary Health Diet” approved by the EAT-Lancet Commission. Our work aims to highlight how a sustainable diet is possible since infancy, since the introduction of solid foods.

The Mediterranean and Nordic Diet: A Review of Differences and Similarities of Two Sustainable, Health-Promoting Dietary Patterns

The Mediterranean diet (MD) and the Nordic diet (ND) share more similarities than differences. Both diets are based on typical local and seasonal foods, share similar nutritional recommendations based on plant-based dietary principles, and are both now orienting toward environmental protection and sustainability. The main difference between the two diets is the primary fat source. Olive oil is the synonym for MD while the ND uses more rapeseed/canola oil. While longitudinal epidemiological studies support adherence to MD as a way to prevent chronic diseases, ND still needs more such studies because the current results are discrepant. Notably, studies that assessed the association between both diets and lower risks of chronic diseases, disability, and mortality from specific and all causes, implied that ND could also have an advantageous effect as MD. Hopefully, there will be more longitudinal and large prospective studies in the future that will provide more evidence-based recommendations.

Development and description of New Nordic Diet scores across infancy and childhood in the Norwegian Mother, Father and Child Cohort Study (MoBa)

In recent years, examining dietary patterns has become a more common way of investigating potential associations between diet and adverse health outcomes. The New Nordic Diet (NND) is a potentially healthy and sustainable dietary pattern characterized by foods that are locally available and traditionally consumed in the Nordic countries. The diet has been typically examined in adult populations, and less is known about compliance to the NND from infancy throughout childhood. In the current study, we therefore aimed to develop and describe child age‐specific NND scores. This study is based on the Norwegian Mother, Father and Child Cohort Study (MoBa) and uses data from the Medical Birth Registry of Norway (MBRN). We have previously developed a NND score for the maternal diet during pregnancy, and the development of the child diet scores was based on the rationale of this score. Food frequency data from n = 89 715 at child age 6 months, n = 76 432 at 18 months, n = 58 884 at 3 years, and n = 35 978 at 7 years were used to construct subscales in accordance with the maternal diet score. Subscales were composed of responses to a selection of food and drink items or other questions and were dichotomized by the median, yielding four age‐specific diet scores where the possible scoring ranged from 0 to 6 at 6 months and 3 years and from 0 to 9 at 18 months and 7 years. The developed scores will be used to examine associations with childhood overweight and cognitive and mental development in future studies.

Can a shift to regional and organic diets reduce greenhouse gas emissions from the food system? A case study from Qatar

BACKGROUND

Qatar is one of the countries with the highest carbon (C) footprints per capita in the world with an increasing population and food demand. Furthermore, the international blockade by some countries that is affecting Qatar-which has been traditionally a highly-dependent country on food imports-since 2017 has led the authorities to take the decision of increasing food self-sufficiency. In this study we have assessed the effect on greenhouse gas (GHG) emissions of shifting diets from conventional to organic products and from import-based diets to more regionalized diets for the first time in a Gulf country.

RESULTS

We found that considering the production system, the majority of the emissions come from the animal products, but the differences between conventional and organic diets are very small (738 and 722 kg CO₂-eq capita^-1 year^-1, of total emissions, respectively). Conversely, total emissions from plant-based products consumption might be around one order of magnitude smaller, but the differences in the emissions between the organic and conventional systems were higher than those estimated for animal products, leading to a decrease in 44 kg CO₂-eq capita^-1 year^-1 when changing from 100% conventional to 50% of organic consumption of plant-based products. Regarding the shift to regionalized diets, we found that packaging has a small influence on the total amount of GHG emissions, whereas emissions from transportation would be reduced in around 450 kg CO₂ capita^-1 year^-1 when reducing imports from 100 to 50%.

CONCLUSIONS

However, these results must be read carefully. Due to the extreme adverse pedoclimatic conditions of the country, commercial organic regional livestock would not be possible without emitting very high GHG emissions and just only some traditional livestock species may be farmed in a climate-friendly way. On the other hand, organic and regional low-CO₂ emission systems of plant-based products would be possible by implementing innovations in irrigation or other innovations whose GHG emissions must be further studied in the future. Therefore, we conclude that shifting towards more plant-based organic regional consumption by using climate-friendly irrigation is a suitable solution to both increasing self-sufficiency and reducing C footprint. We encourage national authorities to including these outcomes into their environmental and food security policies.

Childhood adherence to a potentially healthy and sustainable Nordic diet and later overweight: The Norwegian Mother, Father and Child Cohort Study (MoBa)

The New Nordic Diet (NND) is a potentially healthy and sustainable dietary pattern represented by locally available and traditionally consumed foods in the Northern countries. The diet has been commonly examined in adult populations, but less is known regarding its potential associations with overweight/obesity in children. We have previously developed child diet scores measuring compliance to the NND at child age 6 and 18 months and 3 and 7 years. In this study, we aimed to describe child and maternal characteristics and assess potential associations between the age‐specific diet scores and child overweight at 8 years. This study is based on the Norwegian Mother, Father and Child Cohort Study (MoBa), including 14,989 mother–child pairs and uses data from the Medical Birth Registry of Norway (MBRN). The scores measured NND compliance as a total score and categorized into low, medium and high NND compliance at each age point. Using logistic regression models, we investigated the association between each age‐specific score and the odds of overweight at 8 years. In crude analyses, adherence to the NND at 6 months was inversely associated with odds of overweight at 8 years in the continuous score (odds ratio = 0.95, 95% CI [0.91, 0.98]) and when comparing high versus low NND adherence (odds ratio = 0.81, 95% CI [0.70, 0.94]). The association was almost entirely attenuated in the adjusted models. In conclusion, child NND adherence up to 7 years of age was not associated with odds of overweight at 8 years in adjusted analyses.

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.

Optimization of the environmental performance of food diets in Peru combining linear programming and life cycle methods

The improvement of diets from a nutritional and health perspective has been a critical policy objective in developing nations for the past few decades. However, the current stress that human populations are exerting on the planet has made it important to assess diets using environmental indicators, such as greenhouse gas (GHG) emissions. Therefore, the main objective of the current study was to propose a methodology in which Life Cycle Assessment results linked to dietary patterns in Peru were combined with nutritional and economic data to optimize diets. For this, a linear programming model was built in which the environmental, nutritional and economic information on a set of 25 dietary patterns in Peru were optimized in order to achieve the environmentally best-performing diet that complies with economic and nutritional standards. The result of the proposed linear program allowed understanding the amount of each individual food product that should be consumed in each city that satisfies all the restrictions included in the model in order to attain the lowest GHG emissions possible. Results demonstrated that GHG reductions in food diets can be attained through optimization. For instance, in the case of Lima the obtained reduction was 6%, lowering the annual per capita footprint linked to food diets to 690 kg CO₂eq, as compared to the current value of 736 kg CO₂eq. From an economic perspective, results show that there are important disparities between cities in terms of increasing or decreasing prices of the market basket. Considering that in most areas of the country food purchase accounts for approximately 50% of household expenditure, it is plausible to assume that food choice is a main carrier to achieve GHG emission mitigations. In this context, the method constitutes a useful tool for policy-makers to push forward joint regulations to improve health-related issues linked to the food diet and food choice together with recommendations to lower the climatic impact of diets.

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.

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

In light of the considerable pressure exerted by food production on the environment, the assessment of the environmental burdens of dietary choices has recently gained interest among the scientific community. Several studies based on life cycle thinking approach agreed that a transition from an omnivorous to either a vegan or vegetarian diets would reduce the environmental impact associated with food consumption. The majority of the studies set the system boundaries up to the retail, excluding the consumption phase and generally do not account for uncertainties. The aim of the present study was to assess how personal consumption choices and behaviour can affect the greenhouse gas emissions generated by three balanced dietary patterns (omnivorous, vegetarian and vegan), defined on the basis of nutritional recommendations for an average Italian man. It took into consideration the uncertainties associated with three elements, namely the greenhouse gas emissions due to the production of the food items, the emissions associated with cooking and the food wasted by consumers. The results of the study highlighted that, despite the higher share of greenhouse gas emissions of the supply chain stages prior to consumption (66%-74% of the total emissions), domestic behaviours have an important influence of the total greenhouse gas emissions of the diet, which can offset the lower GHG emissions due to the choice of vegetable-origin foods. In fact, 15%-21% of the total emissions are associated to the cooking phase and 11%-13% to the food waste generation. Therefore, this study remarks the importance of adopting a cradle to grave perspective when assessing the environmental burden of dietary patterns and emphasises the central role of consumers in the definition of low GHG-emitting dietary patterns.

Perspective: Food-Based Dietary Guidelines in Europe-Scientific Concepts, Current Status, and Perspectives

Food-based dietary guidelines (FBDGs) are important tools for nutrition policies and public health. FBDGs provide guidelines on healthy food consumption and are based on scientific evidence. In the past, disease prevention and nutrient recommendations dominated the process of establishing FBDGs. However, scientific advances and social developments such as changing lifestyles, interest in personalized health, and concerns about sustainability require a reorientation of the creation of FBDGs to include a wider range of aspects of dietary behavior. The present review evaluates current European FBDGs with regard to the concepts and aspects used in their derivation, and summarizes the major aspects currently discussed to be considered in future establishment or updates of FBDGs. We identified English information on official European FBDGs through an Internet search (FAO, PubMed, Google) and analyzed the aspects used for their derivation. Furthermore, we searched literature databases (PubMed, Google Scholar) for conceptional considerations dealing with FBDGs. A total of 34 out of 53 European countries were identified as having official FBDGs, and for 15 of these, documents with information on the scientific basis could be identified and described. Subsequently, aspects underlying the derivation of current FBDGs and aspects considered in the literature as important for future FBDGs were discussed. Eight aspects were identified: diet-health relations, nutrient supply, energy supply, dietary habits, sustainability, food-borne contaminants, target group segmentation, and individualization. The first 4 have already been widely applied in existing FBDGs; the others have almost never been taken into account. It remains a future challenge to (re)conceptionalize the development of FBDGs, to operationalize the aspects to be incorporated in their derivation, and to convert concepts into systematic approaches. The current review may assist national expert groups and clarifies the options for future development of local FBDGs.

Dietary changes needed to improve diet sustainability: are they similar across Europe?

Background/objectives

It is not known whether dietary changes able to simultaneously achieve nutritional adequacy and reduce diet-related greenhouse gas emissions (GHGE) are similar across Europe when cultural and gender specificities are taken into account.

Subjects/methods

Starting from each mean observed diet in five European countries (France, UK, Italy, Finland, and Sweden) and for each gender, nutritionally adequate diets departing the least from observed diet were designed with linear programming by applying stepwise 10% GHGE reductions. Other models directly minimized GHGE.

Results

For most countries and whatever the gender, achieving nutritional adequacy implied between-food-group subtitutions (i.e., replacing items from the sugar/fat/alcohol food-group with items from the fruit and vegetables and starchy food-groups), but increased GHGE. Once nutritional adequacy was met, to decrease GHGE, the optimization process further induced within-food-groups substitutions that were reinforced by stepwise GHGE reductions. Diet modeling results showed the need for changes in consumption of animal-based products but those changes differed according to country and gender, particularly for fish, poultry, and non-liquid milk dairy. Depending on country and gender, maximal GHGE reductions achievable ranged from 62% to 78% but they induced large departures from observed diets (at least 2.8 kg/day of total absolute weight change) by modifying the quantity of at least 99% of food items.

Conclusions

Setting nutritional goals with no consideration for the environment may increase GHGE. However, diet sustainability can be improved by substituting food items from the sugar/fat/alcohol food group with fruit, vegetables, and starches, and country-specific changes in consumption of animal-based products. Standardized surveys and individual diet modeling are promising tools for further exploring ways to achieve sustainable diets in Europe.

Evaluating the environmental impacts of dietary recommendations

Dietary choices drive both health and environmental outcomes. Information on diets come from many sources, with nationally recommended diets (NRDs) by governmental or similar advisory bodies the most authoritative. Little or no attention is placed on the environmental impacts within NRDs. Here we quantify the impact of nation-specific NRDs, compared with an average diet in 37 nations, representing 64% of global population. We focus on greenhouse gases (GHGs), eutrophication, and land use because these have impacts reaching or exceeding planetary boundaries. We show that compared with average diets, NRDs in high-income nations are associated with reductions in GHG, eutrophication, and land use from 13.0 to 24.8%, 9.8 to 21.3%, and 5.7 to 17.6%, respectively. In upper-middle-income nations, NRDs are associated with slight decrease in impacts of 0.8-12.2%, 7.7-19.4%, and 7.2-18.6%. In poorer middle-income nations, impacts increase by 12.4-17.0%, 24.5-31.9%, and 8.8-14.8%. The reduced environmental impact in high-income countries is driven by reductions in calories (∼54% of effect) and a change in composition (∼46%). The increased environmental impacts of NRDs in low- and middle-income nations are associated with increased intake in animal products. Uniform adoption of NRDs across these nations would result in reductions of 0.19-0.53 Gt CO2 eq⋅a-1, 4.32-10.6 Gt [Formula: see text] eq⋅a-1, and 1.5-2.8 million km2, while providing the health cobenefits of adopting an NRD. As a small number of dietary guidelines are beginning to incorporate more general environmental concerns, we anticipate that this work will provide a standardized baseline for future work to optimize recommended diets further.

Dietary Strategies to Reduce Environmental Impact: A Critical Review of the Evidence Base

The food system is a major source of environmental impact, and dietary change has been recommended as an important and necessary strategy to reduce this impact. However, assessing the environmental performance of diets is complex due to the many types of foods eaten and the diversity of agricultural production systems and local environmental settings. To assess the state of science and identify knowledge gaps, an integrative review of the broad topic of environment and diet was undertaken, with particular focus on the completeness of coverage of environmental concerns and the metrics used. Compared with the 14 discrete environmental areas of concern identified in the United Nations Sustainable Development Goals, the located journal literature mainly addressed greenhouse gas (GHG) emissions and, to a lesser extent, land and water use. Some relevant concerns were rarely addressed or not addressed at all. In the case of GHG emissions, changes in land use and soil carbon stocks were seldom considered. This represents a disconnect between the science informing strategic climate action in the agricultural sector and the science informing public health nutrition. In the case of land and water use, few studies used metrics that are appropriate in a life-cycle context. Some metrics produce inherently biased results, which misinform about environmental impact. The limited evidence generally points to recommended diets having lower environmental impacts than typical diets, although not in every case. This is largely explained by the overconsumption of food energy associated with average diets, which is also a major driver of obesity. A shared-knowledge framework is identified as being needed to guide future research on this topic. Until the evidence base becomes more complete, commentators on sustainable diets should not be quick to assume that a dietary strategy to reduce overall environmental impact can be readily defined or recommended.