Reducing energy intake and energy density for a sustainable diet: a study based on self-selected diets in French adults

Multicriteria Measures to Assess the Sustainability of Diets: A Systematic Review

CONTEXT

Assessing the overall sustainability of a diet is a challenging undertaking requiring a holistic approach capable of addressing the multicriteria nature of this concept.

OBJECTIVE

The aim was to identify and summarize the multicriteria measures used to assess the sustainability characteristics of diets reported at the individual level by healthy adults.

DATA SOURCES

Articles were identified via PubMed, Scopus, and Web of Science. The search strategy consisted of key words and MeSH terms, and was concluded in September 2022, covering references in English, Spanish, and Portuguese.

DATA EXTRACTION

This systematic review followed the PRISMA guidelines. The search identified 5663 references, from which 1794 were duplicates. Two reviewers independently screened the titles and abstracts of each of the 3869 records and the full-text of the 144 references selected. Of these, 7 studies met the inclusion criteria.

DATA ANALYSIS

A total of 6 multicriteria measures were identified: 3 different Sustainable Diet Indices, the Quality Environmental Costs of Diet, the Quality Financial Costs of Diet, and the Environmental Impact of Diet. All of these incorporated a health/nutrition dimension, while the environmental and economic dimensions were the second and the third most integrated, respectively. A sociocultural sustainability dimension was included in only 1 of the measures.

CONCLUSION

Despite some methodological concerns in the development and validation process of the identified measures, their inclusion is considered indispensable in assessing the transition towards sustainable diets in future studies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42022358824.

Environmental impact and nutritional quality of adult diet in France based on fruit and vegetable intakes

PURPOSE

To describe the nutritional quality and environmental impact of self-selected diets of adults in France in relation to their fruit and vegetable (FV) intakes.

METHODS

Estimates of food and nutrient intakes were taken from the national INCA3 Survey on food intakes carried out in France in 2014-2015. The population (n = 2121 adults) was split into five quintiles of FV intakes, in g/d (Q1 representing the lowest intake, and Q5 the highest). The nutritional quality of diets was assessed through 4 indicators: mean adequacy ratio (MAR), solid energy density, mean excess ratio (MER) and Programme National Nutrition Santé guideline score 2 (PNNS-GS2). The environmental impacts were measured with environmental footprint (EF) scores and 4 additional indicators: climate change, ozone depletion, fine particulate matter and water use. Indicators were compared between quintiles. Analysis was conducted on diets adjusted to 2000 kcal.

RESULTS

MAR and PNNS-GS2 increased with increased FV quintiles, while solid energy density decreased. Fibre, potassium, vitamin B9 and vitamin C densities increased with increasing FV intakes. Climate change, ozone depletion and fine particulate matter impacts of diets decreased with increasing quintiles of FV consumption. Conversely, water use impact increased.

CONCLUSION

Higher intake of FV is associated with higher nutritional quality of diets and lower environmental impact, except for water use. Given the benefits of fruit and vegetables for human health and the environment, their negative impact on water use could be improved by working on the agricultural upstream, rather than by changing individuals' food choices and reducing their consumption.

Identification of three dietary groups in French university students and their associations with nutritional quality and environmental impact

Introduction

The student period is associated with changes in eating habits, usually leading to diets of lower nutritional quality. However, some variability may exist in students' dietary patterns. We aimed to describe French students' diets and identify dietary groups that may vary in nutritional quality and environmental impact.

Methods

A representative sample of French students (N = 582) for age, sex and scholarship status completed an online 125-item food frequency questionnaire. The nutritional quality of diets was assessed by a score of adherence to the French nutritional guidelines (sPNNS-GS2 score, ranging from-17 to 11.5) and its environmental impact by greenhouse gas emissions for an isocaloric diet (GHGE). An ascending hierarchical classification analysis on food and beverage intakes led to three dietary groups. Between-group differences in food consumption, dietary indicators and sociodemographic characteristics were investigated using ANOVA models.

Results

The average sPNNS-GS2 score of students' diets was -0.8 ± 2.8, representing a 57% coverage of French nutritional recommendations, and GHGE were 5.4 ± 1.7 kg eCO2/2000 kcal. The three dietary groups were: a healthy diet group (20% of the sample) with the highest nutritional quality and high GHGE, which included older students with a higher level of physical activity; a Western diet group (40%) with the worst nutritional quality and high GHGE, which included more students who lived with their parents; and a frugal diet group (40%) with the lowest energy intake, intermediate nutritional quality, and low GHGE, which included more students who lived alone.

Conclusion

None of the dietary groups optimized both nutritional quality and environmental impact simultaneously, which suggests an apparent incompatibility in the student population between these two sustainability dimensions. These findings emphasize the need for tailored public health policies that acknowledge the diversity of student eating patterns and address specific individual barriers to healthy and sustainable diets.

Exploring Benefits and Barriers of Plant-Based Diets: Health, Environmental Impact, Food Accessibility and Acceptability

Unhealthy dietary patterns are directly linked to the current Global Syndemic consisting of non-communicable diseases, undernutrition and climate change. The dietary shift towards healthier and more sustainable plant-based diets is essential. However, plant-based diets have wide intra differences; varying from vegan diets that totally exclude meat and animal products to traditional ones such as the Mediterranean diet and the new Nordic diet. It is acknowledged that plant-based diets may contribute simultaneously to improving population health as well as to decreasing the environmental impact of food systems. Evidence from cohort and randomized-controlled trials suggests that plant-based dietary patterns have beneficial effects on bodyweight control, cardiovascular health and diabetes prevention and treatment. On the other hand, micronutrient requirements may not be met, if some plant-based diets are not well-planned. Additionally, studies showed that lower consumption of meat and animal products results in lower environmental impacts. Consequently, plant-based diets could be a key factor to increase diet sustainability. This narrative review addresses the advantages of adherence to plant-based diets on human and planetary health considering strains and barriers to achieve this dietary transition, including cultural acceptability and affordability factors. Finally, potential intervention and policy recommendations are proposed, focusing on the update of current national food-based dietary guidelines.

New insights in improving sustainability in meat production: opportunities and challenges

Treating livestock as senseless production machines has led to rampant depletion of natural resources, enhanced greenhouse gas emissions, gross animal welfare violations, and other ethical issues. It has essentially instigated constant scrutiny of conventional meat production by various experts and scientists. Sustainably in the meat sector is a big challenge which requires a multifaced and holistic approach. Novel tools like digitalization of the farming system and livestock market, precision livestock farming, application of remote sensing and artificial intelligence to manage production and environmental impact/GHG emission, can help in attaining sustainability in this sector. Further, improving nutrient use efficiency and recycling in feed and animal production through integration with agroecology and industrial ecology, improving individual animal and herd health by ensuring proper biosecurity measures and selective breeding, and welfare by mitigating animal stress during production are also key elements in achieving sustainability in meat production. In addition, sustainability bears a direct relationship with various social dimensions of meat production efficiency such as non-market attributes, balance between demand and consumption, market and policy failures. The present review critically examines the various aspects that significantly impact the efficiency and sustainability of meat production.

Dietary Greenhouse Gas Emissions and Diet Quality in a Cross-Sectional Study of Swedish Adolescents

BACKGROUND

Interventions to improve dietary intake and reduce dietary greenhouse gas emissions (dGHGE) are urgently needed. Adolescence presents a unique time in life to promote sustainable diets. Detailed dietary data are needed to inform public health strategies aiming at improving adolescents' diet quality and reducing dGHGE.

OBJECTIVE

This study aimed to describe dGHGE in Swedish adolescents' diets by socio-demographic characteristics, evaluate how food groups contribute to dGHGE, and examine dGHGE in relation to diet quality.

METHODS

Data come from the national, school-based, cross-sectional dietary survey Riksmaten Adolescents 2016-17 of 3099 females and males attending school grades 5 (11-12 y old), 8 (14-15 y old) and 11 (17-18 y old). Participants completed 2 web-based 24-h recalls and questionnaires on lifestyle factors. dGHGE was estimated based on life cycle assessment data. Diet quality was estimated using NRF11.3 (Nutrient Rich Food Index) and SHEIA15 (Swedish Healthy Eating Index for Adolescents 2015).

RESULTS

dGHGE were higher in males than females (medians 4.2 versus 3.8 kg CO2e/10 MJ, P < 0.001). In females, dGHGE were highest in grade 5 (4.0 kg CO2e/10MJ), whereas in males, emissions were highest in grade 11 (4.4 kg CO2e/10MJ), P < 0.001 for the sex/grade interaction. Overweight/obesity was positively associated with CO2e/10MJ, but parental education, birthplace, and degree of urbanization were not. In females, the proportion of dGHGE from animal-based foods was lowest in grade 11, whereas the proportions from plant-based foods and sweet foods/beverages were highest. In males, these proportions were similar across grades. NRF11.3 was not associated with CO2e/10MJ, whereas healthier eating, according to SHEIA15, was inversely associated with CO2e/10MJ.

CONCLUSIONS

Food choices and dGHGE per calorie differ by sex in adolescents. Thus, intervention strategies to improve dietary sustainability need to be tailored differently to females and males. Diet quality should also be considered when promoting reduced GHGE diets.

Technological interventions in improving the functionality of proteins during processing of meat analogs

Meat analogs have opened a new horizon of opportunities for developing a sustainable alternative for meat and meat products. Proteins are an integral part of meat analogs and their functionalities have been extensively studied to mimic meat-like appearance and texture. Proteins have a vital role in imparting texture, nutritive value, and organoleptic attributes to meat analogs. Processing of suitable proteins from vegetable, mycoproteins, algal, and single-cell protein sources remains a challenge and several technological interventions ranging from the isolation of proteins to the processing of products are required. The present paper reviews and discusses in detail various proteins (soy proteins, wheat gluten, zein, algal proteins, mycoproteins, pulses, potato, oilseeds, pseudo-cereals, and grass) and their suitability for meat analog production. The review also discusses other associated aspects such as processing interventions that can be adapted to improve the functional and textural attributes of proteins in the processing of meat analogs (extrusion, spinning, Couette shear cell, additive manufacturing/3D printing, and freeze structuring). '.

Effect of personalized dietary advice to increase protein intake on food consumption and the environmental impact of the diet in community-dwelling older adults: results from the PROMISS trial

PURPOSE

Diet modelling studies suggest that increasing protein intake with no consideration for sustainability results in a higher environmental impact on the diet. To better understand the impact in real life, the aim of this study was to assess the effect of dietary advice to increase protein intake on food consumption and the environmental impact of the diet in community-dwelling older adults.

METHODS

Food consumption and environmental impact were analyzed among 124 Dutch older adults with lower habitual protein intake (< 1.0 g/kg adjusted body weight/day) participating in the six-month PROMISS trial. Dietary intake data from three 24-h dietary recalls, aided by food diaries, and results from life cycle assessments were used to examine the differences in changes in food consumption and environmental impact between those who received dietary advice to isocalorically increase protein intake to ≥ 1.2 g/kg aBW/d (Protein + ; n = 84) and those who did not receive dietary advice (Control; n = 40).

RESULTS

Compared to the Control, Protein + increased protein intake from animal-based food products (11.0 g protein/d, 95% CI 6.6-15.4, p < 0.001), plant-based food products (2.1 g protein/d, 95% CI 0.2-4.0, p = 0.031) and protein-enriched food products provided during the trial (18 g protein/d, 95% CI 14.5-21.6, p < 0.001) at the 6-month follow-up. Diet-associated greenhouse gas emissions increased by 16% (p < 0.001), land use by 19% (p < 0.001), terrestrial acidification by 20% (p = 0.01), and marine eutrophication by 16% (p = 0.035) in Protein + compared to the Control.

CONCLUSION

This study found that dietary advice increased protein intake, favoring animal-based protein, and increased the environmental impact of the diet in older adults.

TRIAL REGISTRATION

ClinicalTrials.gov. NCT03712306. October 2018.

Sustainability of Diets in Mexico: Diet Quality, Environmental Footprint, Diet Cost, and Sociodemographic Factors

Background

Little is known about the current intake of sustainable diets globally and specifically in middle-income countries, considering nutritional, environmental and economic factors.

Objective

To assess and characterize the sustainability of Mexican diets and their association with sociodemographic factors.

Design

Dietary data of 2,438 adults within the National Health and Nutrition Survey 2012 by integrating diet quality measured by the Healthy Eating Index (HEI-2015), diet cost, and four environmental indicators were analyzed: land use (LU), biodiversity loss (BDL), carbon footprint (CFP), and blue water footprint (BWFP). We defined healthier more sustainable diets (MSD) as those with HEI-2015 above the overall median, and diet cost and environmental indicators below the median. Logistic regression was used to evaluate the association of sociodemographic factors with MSD.

Results

MSD were consumed by 10.2% of adults (4% of urban and 22% of rural), who had lower intake of animal-source foods, unhealthy foods (refined grains, added sugar and fats, mixed processed dishes and sweetened beverages), fruits, and vegetables, and higher intake of whole grains than non-MSD subjects. Characteristics of MSD vs. non-MSD (urban; rural) were: HEI-2015 (62.6 vs. 51.9; 66.8 vs. 57.6), diet-cost (1.9 vs. 2.8; 1.9 vs. 2.5 USD), LU (3.3 vs. 6.6; 3.2 vs. 5.9 m2), BDL (105 vs. 780; 87 vs. 586 species × 10-10), BWFP (244 vs. 403; 244 vs. 391 L), and CFP (1.6 vs. 4.4; 1.6 vs. 3.7 kg CO2eq). Adults from rural vs. urban (OR 2.7; 95% CI: 1.7, 4.1), or from the South (OR 2.1; 95% CI: 1.1, 3.9), Center (OR 2.3; 95% CI: 1.3, 4.4) vs. the North were more likely to consume MSD, while adults with high vs. low socioeconomic status were less likely (OR 0.17; 95% CI: 0.09, 0.3).

Conclusions

The MSD is a realistic diet pattern mainly found in disadvantaged populations, but diet quality is still sub-optimal. Increased consumption of legumes, fruits, and vegetables, and a reduction in unhealthy foods, is required to improve nutritional quality of diets while ensuring their environmental sustainability.

Food-Level Analysis to Identify Dietary Choices With the Highest Nutritional Quality and Lowest Greenhouse Gas Emissions and Price

Introduction

Food systems are challenged to provide healthy, sustainable and affordable foods. From a consumer perspective, identifying healthy, sustainable and affordable choices based on individual food products rather than diets could promote better shopping choices.

Objective

To identify foods and drinks with the highest nutritional quality and lowest greenhouse gas emissions (GHGE) and price. We also assessed how a combination of these indicators (e.g., nutritional quality, GHGE and price) for food categories aligned with current United Kingdom dietary recommendations.

Materials and Methods

We performed a secondary analysis of the National Diet and Nutrition Survey (NDNS) nutrient databank year 11 (2018/2019). Spearman correlation coefficients were used to assess the strength of relationships between nutritional quality, environmental impact and/or prices per 100 kcal. In addition, we developed an optimized nutritional quality, GHGE and price score for each food or drink item based on the overall medians for each of these indicators.

Results

Median nutritional value was highest for fruit and vegetables, whilst median GHGE and price was lower for starchy carbohydrates, fats and items of which consumption should be limited. The relative proportions of foods considered the most nutritious and with a low GHGE and price in each of the food categories, on a per 100 kcal basis, were comparable to the proportions in the Eatwell Guide, except for the proportion of fruits and vegetables being smaller and the proportion of potatoes, bread, rice, pasta, and other starchy carbohydrates being larger in our analysis.

Conclusion

Public health efforts should consider the impact of dietary choices not only in terms of nutritional quality but also in terms of environmental and economic impact. Our food-based analysis shows a large variation in nutritional quality, GHGE and price within and across food categories, which provides consumers with opportunities for "food swaps" that are more nutritious and have lower GHGE and price.

An Evaluation of Probability of Adequate Nutrient Intake (PANDiet) Scores as a Diet Quality Metric in Irish National Food Consumption Data

Identifying reliable metrics which measure the quality of a diet to promote nutrient adequacy and long-term health is an important step in the development of a sustainable food system. The Probability of Adequate Nutrient Intake (PANDiet) scoring system has been used as a measure of dietary quality in interdisciplinary research in recent years. The aim of the current study is to apply the PANDiet scoring system, and to assess the validity of the score as a metric of nutritional adequacy, within the Irish population. The Irish National Adult Nutrition Survey is a representative database with detailed data on nutrient intakes (18−90 years; n = 1051 valid-reporters; 2008−2010) and biofluid analytes (blood n = 786; urine n = 778). The PANDiet scoring system was expanded to include seven macronutrients, twelve micronutrients, nine minerals, and total energy using an established methodology. PANDiet scores were assessed against the Alternate Healthy Eating Index (AHEI) and Alternate Mediterranean Diet (aMED) food-based scores. The average score for the population (μ) was 63.69 ± 0.23 and ranged from 38.27 to 89.74. Higher PANDiet scores were significantly associated with males, higher educated participants, non-smokers, and low-energy-dense diets (p < 0.001). Females between the ages of 18 and 35 had a significantly lower nutrient adequacy score (μ 59.17). PANDiet scores were significantly correlated with serum folate, riboflavin status, serum vitamin D (p < 0.05) and with AHEI and aMED scores (Rs 0.45 and 0.43, p < 0.0001). The nutritional contribution of food groups varied between genders and low, moderate, and high nutritional adequacy groups. The PANDiet scoring system facilitated a detailed analysis of nutritional adequacy across sub-groups of the population, and is a comprehensive and valid diet quality metric in Irish databases.

Sustainable Diets as Tools to Harmonize the Health of Individuals, Communities and the Planet: A Systematic Review

Background. Climate change and global health are inextricably linked. Thus, health systems and their professionals must adapt and evolve without losing quality of care. Aim(s). To identify health and environmental co-benefits derived from a sustainable diet and promotion strategies that favor its implementation. Methods. A systematic search for articles published on sustainable diets and human/planetary health published between 2013 and 2020 was conducted on the databases PubMed, Cinahl, Scopus and Trip from 4 to 7 May 2020 in accordance with the PRISMA guideline. Results. A total of 201 articles was retrieved, but only 21 were included. A calorie-balanced diet mainly based on food of plant origin that would allow the attainment of 60% of daily caloric requirements and a low protein intake from animal foods (focusing in fish and poultry) could significantly reduce global morbi-mortality and the dietary environmental impact maintaining a framework of sustainability conditioned by the consumption of fresh, seasonal, locally produced and minimally packaged products. Discussion. The implementation of sustainable diets requires working on the triangulation of concepts of food–health–environment from schools and that is permanently reinforced during all stages of the life by healthcare workers, who should establish the appropriate modifications according to the age, gender and health situation.

Advantages and limitations of the methodological approaches used to study dietary shifts towards improved nutrition and sustainability

Acting on diet is one of the changes required - in combination with actions on food production, transformation, and waste - to address the challenges of reducing the environmental impact of our food systems and eliminating all forms of malnutrition. The number of studies exploring how to move towards a more sustainable diet has exploded over the past decades, but there is a need to facilitate their understanding and use by policy makers and all other stakeholders possibly influencing diet sustainability. The aim of the present article is to propose a categorization of studies into 4 approaches, based on the type of methodology used to explore diet sustainability, and to highlight the principles, advantages, and limitations of each approach in order to help study users in their interpretation. The 4 approaches are: assessment of sustainability characteristics of hypothetical diets (approach 1) or existing diets (approach 2), identification of existing "positive deviants" (approach 3), and design of more sustainable diets with constrained optimization (approach 4). Specificities and key findings drawn from each approach are described, and challenges for future studies are discussed.

Investigating Web-Based Nutrition Education Interventions for Promoting Sustainable and Healthy Diets in Young Adults: A Systematic Literature Review

Background: Our current rapidly growing food systems are imposing a heavy burden on both environmental sustainability and human health. Sustainable and healthy diets aim to promote optimal health and have a minimal environmental impact. This study aimed to critically review and synthesise the evidence on the effectiveness of web-based nutrition education interventions aiming to promote sustainable and healthy diets among young adults. Methods: A systematic search of four databases (Medline, PsycINFO, Scopus, and Embase) was conducted in March 2021. Studies were included if they used an online platform to deliver the intervention to young adults and measured at least one aspect of sustainable and healthy diets, such as plant-based food intake, food waste, and local and seasonal produce. Of the 2991 studies, a total of 221 full-text articles were assessed for eligibility of which 22 were included in the final review. Results: A majority of the studies (82%) targeted fruit and vegetable consumption, and close to a quarter of studies (23%) targeted other aspects of a sustainable and healthy diet, such as red meat intake. Only one study included multiple aspects of a sustainable and healthy diet. Program delivery outcomes reported overall positive feedback and engagement. Conclusion: This review suggests that web-based interventions may be effective in promoting some sustainable diet-related outcomes in young adults. However, there is a need for developing and evaluating future programs to promote sustainable diets more comprehensively in order to help young adults make healthy and sustainable food choices.

A Scoping Review of Indicators for Sustainable Healthy Diets

Introduction: Diets are currently unsustainable in many countries as evidenced by the growing burden of malnutrition, degradation of natural resources, contributions to climate change, and unaffordability of healthy diets. Agreement on what constitutes a healthy and sustainable diet has been debated. In 2019, FAO and WHO published the Sustainable Healthy Diets Guiding Principles, defining what qualifies as a sustainable healthy diet. While valuable, these principles require measurable indicators to support their operationalization. Our scoping review aims to describe how sustainable healthy diets have been assessed in the literature since 2010.

Methods: A search for English-language articles published in peer-reviewed journals was conducted from January 2010 through February 2020 across three databases. Out of the 504 articles initially identified, 103 articles were included. Metadata were extracted from each article on: publication year, country of study, study aims, methods, main data sources, indicators used to assess sustainable healthy diets, reported indicator strengths or limitations, and main study findings. A qualitative content analysis identified major conceptual themes across indicators and their frequency of use.

Findings: From the 103 empirical articles included in our review, 57.3% were published after 2017. Most studies were carried out in high-income countries (74%). Approximately 42% of the articles assessed the sustainability of diets using solely health and environmental indicators; &lt;25% assessed the sustainability of diets across health, environmental, and sociocultural aspects of sustainability. We found a substantial number of unique indicators used for assessing health (n = 82), environmental (n = 117), and sociocultural (n = 43) aspects of diets. These indicators covered concepts related to health outcomes, aspects of diet quality, natural resources, climate change, cultural acceptability, and cost of diets. The preponderance of indicators currently used in research likely poses challenges for stakeholders to identify the most appropriate measures.

Conclusion: Robust indicators for sustainable healthy diets are critical for understanding trends, setting targets, and monitoring progress across national and sub-national levels. Our review highlights the geographical imbalance, the narrow focus on health and environmental aspects, and the lack of common measures used in research. Measures registries could provide the decision-support needed by stakeholders to aid in the indicator selection process.

Association between the socio-economic status of households and a more sustainable diet

OBJECTIVE

A sustainable diet is an affordable diet with low environmental impact, high food security and sufficient healthiness. The present study aimed to assess the correlation between the socio-economic status of households and a sustainable diet.

DESIGN

The food basket and socio-economic data of Iranian households were evaluated during 2016-2018. The households were classified based on the sustainability of their diet by determining the dietary carbon footprint, dietary water footprint, lower dietary costs of the household than the median and a higher dietary quality index than the median. Logistic regression was used with four models to calculate the OR of a more sustainable diet as the dependent variable regarding the different quartiles of socio-economic status (SES) as the independent variable.

SETTING

Iran.

PARTICIPANTS

Iranian households (n 102 303), nationally representative, were studied.

RESULTS

Lower SES was associated with the higher OR of a sustainable diet (OR: 0·90; (95 % CI 0·87, 0·91)). Higher quartiles of SES compared with the lower SES group indicated the higher energy intake and consumption of more dairies, meat, poultry, fish, eggs, legumes, nuts and fruits, as well as the lower intake of bread, cereal, rice and pasta.

CONCLUSION

In countries such as Iran, where nutrition transition occurs rapidly, better economic and social levels in the populations with a higher SES are associated with increased energy intake and higher consumption of animal-based foods, which decreases sustainable diets compared with the groups with a lower SES.

Variations in greenhouse gas emissions of individual diets: Associations between the greenhouse gas emissions and nutrient intake in the United Kingdom

BACKGROUND

Food production accounts for 30% of global greenhouse gas (GHG) emissions. Less environmentally sustainable diets are also often more processed, energy-dense and nutrient-poor. To date, the environmental impact of diets have mostly been based on a limited number of broad food groups.

OBJECTIVES

We link GHG emissions to over 3000 foods, assessing associations between individuals' GHG emissions, their nutrient requirements and their demographic characteristics. We also identify additional information required in dietary assessment to generate more accurate environmental impact data for individual-level diets.

METHODS

GHG emissions of individual foods, including process stages prior to retail, were added to the UK Composition Of Foods Integrated Dataset (COFID) composition tables and linked to automated online dietary assessment for 212 adults over three 24-hour periods. Variations in GHG emissions were explored by dietary pattern, demographic characteristics and World Health Organization Recommended Nutrient Intakes (RNIs).

RESULTS

GHG emissions estimates were linked to 98% (n = 3233) of food items. Meat explained 32% of diet-related GHG emissions; 15% from drinks; 14% from dairy; and 8% from cakes, biscuits and confectionery. Non-vegetarian diets had GHG emissions 59% (95% CI 18%, 115%) higher than vegetarian. Men had 41% (20%, 64%) higher GHG emissions than women. Individuals meeting RNIs for saturated fats, carbohydrates and sodium had lower GHG emissions compared to those exceeding the RNI.

DISCUSSION

Policies encouraging sustainable diets should focus on plant-based diets. Substituting tea, coffee and alcohol with more sustainable alternatives, whilst reducing less nutritious sweet snacks, presents further opportunities. Healthier diets had lower GHG emissions, demonstrating consistency between planetary and personal health. Further detail could be gained from incorporating brand, production methods, post-retail emissions, country of origin, and additional environmental impact indicators.

The global and regional costs of healthy and sustainable dietary patterns: a modelling study

BACKGROUND

Adoption of healthy and sustainable diets could be essential for safe-guarding the Earth's natural resources and reducing diet-related mortality, but their adoption could be hampered if such diets proved to be more expensive and unaffordable for some populations. Therefore, we aimed to estimate the costs of healthy and sustainable diets around the world.

METHODS

In this modelling study, we used regionally comparable food prices from the International Comparison Program for 150 countries. We paired those prices with estimates of food demand for different dietary patterns that, in modelling studies, have been associated with reductions in premature mortality and environmental resource demand, including nutritionally balanced flexitarian, pescatarian, vegetarian, and vegan diets. We used estimates of food waste and projections of food demand and prices to specify food system and socioeconomic change scenarios up to 2050. In the full cost accounting, we estimated diet-related health-care costs by pairing a comparative risk assessment of dietary risks with cost-of-illness estimates, and we estimated climate change costs by pairing the diet scenarios with greenhouse gas emission footprints and estimates of the social cost of carbon.

FINDINGS

Compared with the cost of current diets, the healthy and sustainable dietary patterns were, depending on the pattern, up to 22-34% lower in cost in upper-middle-income to high-income countries on average (when considering statistical means), but at least 18-29% more expensive in lower-middle-income to low-income countries. Reductions in food waste, a favourable socioeconomic development scenario, and a fuller cost accounting that included the diet-related costs of climate change and health care in the cost of diets increased the affordability of the dietary patterns in our future projections. When these measures were combined, the healthy and sustainable dietary patterns were up to 25-29% lower in cost in low-income to lower-middle-income countries, and up to 37% lower in cost on average, for the year 2050. Variants of vegetarian and vegan dietary patterns were generally most affordable, and pescatarian diets were least affordable.

INTERPRETATION

In high-income and upper-middle-income countries, dietary change interventions that incentivise adoption of healthy and sustainable diets can help consumers in those countries reduce costs while, at the same time, contribute to fulfilling national climate change commitments and reduce public health spending. In low-income and lower-middle-income countries, healthy and sustainable diets are substantially less costly than western diets and can also be cost-competitive in the medium-to-long term, subject to beneficial socioeconomic development and reductions in food waste. A fuller accounting of the costs of diets would make healthy and sustainable diets the least costly option in most countries in the future.

FUNDING

Global Panel on Agriculture and Food Systems for Nutrition and Wellcome Trust.

Secular trends in diet-related greenhouse gas emission estimates since 2000 - a shift towards sustainable diets in Sweden

Objective:

This study examines secular changes in diet-related greenhouse gas emissions (GHGE) in younger and older Swedish adults, since the turn of this century.

Design:

Two cross-sectional health examination surveys were conducted in 2001–2004 (T₁) and 2014–2018 (T₂). At both times, an eighty-six-item FFQ was embedded in the survey. From the food frequencies and age-standardised portion sizes, GHGE estimates (kg CO₂e/year) were calculated. GHGE was modelled as a function of time period and covariates, for five distinct age groups.

Setting:

The municipality of Gothenburg, in western Sweden.

Participants:

Women and men aged 25–34, 35–44, 45–54, 55–64 and 65–75 years were randomly selected from the population registry and recruited for examinations. After exclusion of participants with incomplete dietary data, the analytic sample consisted of 2569 individuals at T₁ and 2119 at T₂.

Results:

Lower dietary GHGE scores were observed at T₂ compared with T₁, in each age group, adjusting for sex, BMI and education. The largest differences in GHGE were observed in the youngest age group (approximately 30 % reduction). Decreasing trends in GHGE from animal-based foods were observed at all ages and were accompanied by smaller increases from plant-based sources in younger groups only. At all ages, GHGE from discretionary foods decreased, and prevalence of overweight remained stable.

Conclusions:

Optimal dietary trends should support both human health and planetary health. Our results suggest that Swedish adults have moved in this direction, e.g. through less intake of red meat products and stable weight status.

Greenhouse gases emissions from the diet and risk of death and chronic diseases in the EPIC-Spain cohort

BACKGROUND

Evidence from the scientific literature shows a significant variation in greenhouse gas (GHG) emissions from the diet, according to the type of food consumed. We aim to analyze the relationship between the daily dietary GHG emissions according to red meat, fruit and vegetables consumption and their relationship with risk of total mortality, and incident risk of chronic diseases.

METHODS

We examined data on the EPIC-Spain prospective study, with a sample of 40 621 participants. Dietary GHG emission values were calculated for 57 food items of the EPIC study using mean emission data from a systematic review of 369 published studies.

RESULTS

Dietary GHG emissions (kgCO2eq/day), per 2000 kcal, were 4.7 times higher in those with high red-meat consumption (>140 g/day) than those with low consumption (<70 g/day). The average dietary GHG emissions were similar in males and females, but it was significantly higher in youngest people and in those individuals with lower educational level, as well as for northern EPIC centers of Spain. We found a significant association with the risk of mortality comparing the third vs. the first tertile of dietary GHG emissions [hazard ratio (HR) 1.095; 95% confidence interval (CI) 1.007-1.19; trend test 0.037]. Risk of coronary heart disease (HR 1.26; 95% CI 1.08-1.48; trend test 0.003) and risk of type 2 diabetes (HR 1.24; 95% CI 1.11-1.38; trend test 0.002) showed significant association as well.

CONCLUSIONS

Decreasing red-meat consumption would lead to reduce GHG emissions from diet and would reduce risk of mortality, coronary heart disease and type 2 diabetes.

Indicators and Recommendations for Assessing Sustainable Healthy Diets

Research coupling human nutrition and sustainability concerns is a rapidly developing field, which is essential to guide governments' policies. This critical and comprehensive review analyzes indicators and approaches to "sustainable healthy diets" published in the literature since this discipline's emergence a few years ago, identifying robust gauges and highlighting the flaws of the most commonly used models. The reviewed studies largely focus on one or two domains such as greenhouse gas emissions or water use, while overlooking potential impact shifts to other sectors or resources. The present study covers a comprehensive set of indicators from the health, environmental and socio-economic viewpoints. This assessment concludes that in order to identify the best food option in sustainability assessments and nutrition analysis of diets, some aspects such as the classification and disaggregation of food groups, the impacts of the rates of local food consumption and seasonality, preservation methods, agrobiodiversity and organic food and different production systems, together with consequences for low-income countries, require further analysis and consideration.

The SHED Index: a tool for assessing a Sustainable HEalthy Diet

PURPOSE

Promoting sustainable diets through sustainable food choices is essential for achieving the sustainable development goals set by the United Nations. Establishing a practical tool that can measure and score sustainable and healthy eating is highly important.

METHODS

We established a 30-item questionnaire to evaluate sustainable-dietary consumption. Based on the literature and a multidisciplinary advisory panel, the questionnaire was computed by principal component analysis, yielding the Sustainable-HEalthy-Diet (SHED) Index. A rigorous multi-stage process included validation in training-verification sets, across recycling efforts, as an indicator of environmental commitment; and validation across the proportion of animal-protein consumption, as an indicator of adherence to a sustainable and healthy dietary-pattern. The EAT-Lancet reference-diet and the Mediterranean-Diet-score were used to investigate the construct validity of the SHED Index score. Reliability was assessed with a test-retest sample.

RESULTS

Three-hundred-forty-eight men and women, aged 20-45 years, completed both the SHED Index questionnaire and a validated Food-Frequency-Questionnaire. Increased dietary animal-protein intake was associated with a lower SHED Index total score (p < 0.001). Higher recycling efforts were associated with a higher total SHED Index score (p < 0.001). A linear correlation was found between the SHED Index score and food-groups of the Eat-Lancet-reference diet. A significant correlation was found between the Mediterranean-Diet-score and the SHED Index score (r = 0.575, p < 0.001). The SHED Index score revealed high reliability in test-retest, high validity in training and verification sets, and internal consistency.

CONCLUSION

We developed the SHED Index score, a simple, practical tool, for measuring healthy and sustainable individual-diets. The score reflects the nutritional, environmental and sociocultural aspects of sustainable diets; and provides a tangible tool to be used in intervention studies and in daily practice.

Diet-related greenhouse gas emissions and major food contributors among Japanese adults: comparison of different calculation methods

OBJECTIVE

To develop a greenhouse gas emissions (GHGE) database for Japanese foods using three different approaches, compare the results of estimated diet-related GHGE and determine major food contributors among Japanese adults.

DESIGN

Cross-sectional. Three GHGE databases were developed: (1) a literature-based method including a literature review of life cycle assessment studies of Japanese foods and (2) production- and (3) consumption-based input-output tables (IOT)-applied methods using the Japanese IOT. All databases were linked to the Japanese food composition table and food consumption data. Diet-related GHGE was estimated based on each database and the 4-d dietary record data. Diet-related GHGE were compared in both total and food group level between the databases.

SETTING

Japan.

PARTICIPANTS

392 healthy adults aged 20-69 years.

RESULTS

The mean diet-related GHGE significantly differed according to the calculation methods: 4145 g CO2-equivalent (CO2-eq)/d by the literature-based method, 4031 g CO2-eq/d by the production-based method and 7392 g CO2-eq/d by the consumption-based IOT-applied methods. It significantly differed in food group level as well. Spearman's correlation coefficients between three methods ranged from 0·82 to 0·86. Irrespective of the methods, the top contributor to GHGE was meat (19·7-28·8 %) followed by fish and seafood (13·8-18·3 %).

CONCLUSIONS

Although the identified major food contributors to GHGE were comparable between the three methods, the estimated GHGE values significantly differed by calculation methods. This finding suggested that caution must be taken when interpreting the estimated diet-related GHGE values obtained using the different calculation methods of GHGE.

A Critical Appraisal of the Evidence Supporting Consumer Motivations for Alternative Proteins

Alternative proteins are receiving increased global attention. This burgeoning interest in plants (especially plant-based meat alternatives), insects, algae, and cultured meat has been attributed to their reported health benefits, lower environmental impact and improved animal welfare compared to conventional animal-based meat. Food producers and the media are promoting acceptance of these products, claiming superior nutritional, environmental and ethical credentials and a desirable novel sensory experience. However, the evidence supporting these claims remains unclear. In this review, we summarise the main evidence underlying the nutritional, sensorial, economical, ethical, and environmental reasons reported for the rise in consumer demand for alternative proteins. We found many of these reasons to lack a strong evidence base. For instance, evidence is emerging for the nutritional benefits of plant-based meat alternatives, but present claims are largely based on established evidence for plant-based diets. Significant research gaps remain, especially longitudinal evidence on the sustained effects of replacing conventional animal-based proteins with alternative sources. For many alternative proteins, challenges exist in achieving desirable sensory properties akin to animal-based meat to promote their acceptance by consumers. Overall, fundamental shifts in the food system are required to create a culture in which healthful and sustainable food choices are the norm.

The next protein transition

Background

Meeting the UN Sustainable Development Goals requires a relatively rapid transition towards a circular economy. Therefore, a multidisciplinary perspective is required to sketch why a transition from diets based primarily on animal proteins towards diets based primarily on plant proteins products is extremely urgent for both food security and sustainability.

Scope and approach

This review starts out by identifying ecological, economic and social aspects of sustainable food consumption. Subsequently, it is argued how protein supply is underlying and linking the top-3 of anthropogenic impacts based on the planetary boundaries concept, i.e. 1) biodiversity loss, 2) nitrogen cycle acceleration, and 3) carbon cycle acceleration (resulting in climate change). These environmental impacts associated with current Western food consumption need to be reduced urgently. In order to address the inefficiencies inherent to current dietary patterns, therefore, a ranked list of more sustainable options is proposed, based on their order of magnitude. Addressing consumers, industry, and governmental stakeholders plus cultural aspects, challenges and options are sketched.

Key findings and conclusions

Clearly, a dietary transition from primarily animal towards plant protein products is required. Fortunately, new dietary guidelines are increasingly taking sustainability into account and the contours of a diet transition are slowly emerging.

Designing a healthy, low-cost and environmentally sustainable food basket: an optimisation study

OBJECTIVE

Sustainable diets are diets with low environmental impacts and high affordability which contribute to food and nutrition security. The present study aimed to develop a healthy, low-cost and environmental-friendly food basket for Iran based on current consumption.

DESIGN

The Households Income and Expenditure Survey data were used. Linear Programming was utilised to obtain the optimal diets, separately, for each goal of the sustainable food basket: (1) Diet with maximum Nutrient Rich Food (NRF) index, (2) Diet with minimum cost, (3) Diet with the minimum water footprint and (4) Diet with the minimum carbon footprint. Goal Programming techniques were used to optimise the sustainable food basket by considering all goals simultaneously.

SETTING

Iran.

PARTICIPANTS

Households (n 100 500) in urban and rural areas of Iran, nationally representative.

RESULTS

In the 'optimal model', compared with the usual consumption, the amount of the 'bread, cereal, rice, and pasta', 'meat, poultry, fish, eggs, legumes, and nuts' and 'fats, oils, sugars, and sweets' groups was decreased. Inside those food groups, cereals, poultry and vegetable oil subgroups were increased. Also, dairy, fruits and vegetable groups were increased. In this model, there was a 14 % reduction in the total water footprint, a 14 % decrease in the total carbon footprint, a 23 % decrease in the cost and a 7 % increase in NRF of diet compared with the usual consumption.

CONCLUSIONS

Increasing the consumption of dairy, fruits and vegetables and reducing the consumption of bread, rice, pasta, meat, fish, eggs, legumes, nuts, hydrogenated fats and sugars are required to achieve a sustainable food basket.

Is the Sustainable Choice a Healthy Choice?-Water Footprint Consequence of Changing Dietary Patterns

It is evident that the modification of dietary patterns is a necessary precondition of disease prevention and health improvement. Changing nutritional habits also has deep-rooted consequences on the environmental burden. The majority of similar previous studies have analyzed the change in greenhouse gas emissions against theoretical modifications in current food consumption. The analysis on the effect of diet on the water footprint is also gaining in importance, since water supply is a critical global issue. Based on current nutritional patterns of a Central European country-Hungary-as well as dietary recommendations and scientific literature, we generated six dietary scenarios and determined the consequences of these on green (originally from precipitation) and blue (sourced from surface or groundwater) water consumption and dietary quality. Compared to the baseline scenario (current local nutritional pattern) of both genders, based on the integrated aspect of water footprint and dietary quality, the most disadvantageous scenario was the ketogenic (ca. -2% in dietary quality, +18% in blue water footprint, and +16% in green water footprint) and the most advantageous was the sustainable scenario (ca. +9% in dietary quality, -42% in green water footprint, and -29% in blue water footprint). As a summary it can be stated, that (1) there is no clear linear relationship between the "healthiness" and water footprint of different diets, but (2) a more balanced diet, which integrates nutritional and environmental considerations could decrease the environmental burden in an efficient way.

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.

Achieving Healthy and Sustainable Diets: A Review of the Results of Recent Mathematical Optimization Studies

Climate protection and other environmental concerns render it critical that diets and agriculture systems become more sustainable. Mathematical optimization techniques can assist in identifying dietary patterns that both improve nutrition and reduce environmental impacts. Here we review 12 recent studies in which such optimization was used to achieve nutrition and environmental sustainability aims. These studies used data from China, India, and Tunisia, and from 7 high-income countries (France, Finland, Italy, the Netherlands, Sweden, the United Kingdom, and the United States). Most studies aimed to reduce greenhouse gas emissions (10 of 12) and half aimed also to reduce ≥1 other environmental impact, e.g., water use, fossil energy use, land use, marine eutrophication, atmospheric acidification, and nitrogen release. The main findings were that in all 12 studies, the diets optimized for sustainability and nutrition were more plant based with reductions in meat, particularly ruminant meats such as beef and lamb (albeit with 6 of 12 of studies involving increased fish in diets). The amount of dairy products also tended to decrease in most (7 of 12) of the studies with more optimized diets. Other foods that tended to be reduced included: sweet foods (biscuits, cakes, and desserts), savory snacks, white bread, and beverages (alcoholic and soda drinks). These findings were broadly compatible with the findings of 7 out of 8 recent review articles on the sustainability of diets. The literature suggests that healthy and sustainable diets may typically be cost neutral or cost saving, but this is still not clear overall. There remains scope for improvement in such areas as expanding research where there are no competing interests; improving sustainability metrics for food production and consumption; consideration of infectious disease risks from livestock agriculture and meat; and researching optimized diets in settings where major policy changes have occurred (e.g., Mexico's tax on unhealthy food).

Greenhouse Gas Emissions and Blue Water Use of Dutch Diets and Its Association with Health

Food consumption patterns affect the environment as well as public health, and monitoring is needed. The aim of this study was to evaluate the Dutch food consumption patterns for environmental (greenhouse gas (GHG) emissions and blue water use) and health aspects (Dutch Healthy Diet index 2015), according to age, gender, and consumption moments. Food consumption data for 4313 Dutch participants aged 1 to 79 years were assessed in 2012 to 2016, by two non-consecutive 24-h recalls. The environmental impact of foods was quantified using a life cycle assessment for, e.g., indicators of GHG emissions and blue water use. The healthiness of diet, operationalized by the Dutch Healthy Diet index 2015, was assessed for 2078 adults aged ≥19 years. The average daily diet in the Netherlands was associated with 5.0 ± 2.0 kg CO2-equivalents of GHG emissions and 0.14 ± 0.08 m3 of blue water use. Meat, dairy and non-alcoholic beverages contributed most to GHG emissions, and non-alcoholic beverages, fruits, and meat to blue water use. More healthy diets were associated with a lower GHG emission and higher blue water use. Different associations of environmental indicators (GHG emissions and blue water use) with health aspects of diets need to be considered when aligning diets for health and sustainability.

Effect of food-related behavioral activation therapy on food intake and the environmental impact of the diet: results from the MooDFOOD prevention trial

Purpose

Food-based dietary guidelines are proposed to not only improve diet quality, but to also reduce the environmental impact of diets. The aim of our study was to investigate whether food-related behavioral activation therapy (F-BA) applying Mediterranean-style dietary guidelines altered food intake and the environmental impact of the diet in overweight adults with subsyndromal symptoms of depression.

Methods

In total 744 adults who either received the F-BA intervention (F-BA group) or no intervention (control group) for 12 months were included in this analysis. Food intake data were collected through a food frequency questionnaire at baseline and after 6 and 12 months. Greenhouse gas emissions (GHGE), land use (LU), and fossil energy use (FEU) estimates from life-cycle assessments and a weighted score of the three (pReCiPe score) were used to estimate the environmental impact of each individual diet at each timepoint.

Results

The F-BA group reported increased intakes of vegetables (19.7 g/day; 95% CI 7.8–31.6), fruit (23.0 g/day; 9.4–36.6), fish (7.6 g/day; 4.6–10.6), pulses/legumes (4.0 g/day; 1.6–6.5) and whole grains (12.7 g/day; 8.0–17.5), and decreased intake of sweets/extras (− 6.8 g/day; − 10.9 to − 2.8) relative to control group. This effect on food intake resulted in no change in GHGE, LU, and pReCiPe score, but a relative increase in FEU by 1.6 MJ/day (0.8, 2.4).

Conclusions

A shift towards a healthier Mediterranean-style diet does not necessarily result in a diet with reduced environmental impact in a real-life setting.

Trial registration

ClinicalTrials.gov. Number of identification: NCT02529423. August 2015.

Electronic supplementary material

The online version of this article (10.1007/s00394-019-02106-1) contains supplementary material, which is available to authorized users.

Measures and metrics of sustainable diets with a focus on milk, yogurt, and dairy products

The 4 domains of sustainable diets are nutrition, economics, society, and the environment. To be sustainable, foods and food patterns need to be nutrient-rich, affordable, culturally acceptable, and sparing of natural resources and the environment. Each sustainability domain has its own measures and metrics. Nutrient density of foods has been assessed through nutrient profiling models, such as the Nutrient-Rich Foods family of scores. The Food Affordability Index, applied to different food groups, has measured both calories and nutrients per penny (kcal/$). Cultural acceptance measures have been based on relative food consumption frequencies across population groups. Environmental impact of individual foods and composite food patterns has been measured in terms of land, water, and energy use. Greenhouse gas emissions assess the carbon footprint of agricultural food production, processing, and retail. Based on multiple sustainability metrics, milk, yogurt, and other dairy products can be described as nutrient-rich, affordable, acceptable, and appealing. The environmental impact of dairy farming needs to be weighed against the high nutrient density of milk, yogurt, and cheese as compared with some plant-based alternatives.

Sustainable Diets in the UK—Developing a Systematic Framework to Assess the Environmental Impact, Cost and Nutritional Quality of Household Food Purchases

Sustainable diets should not only respect the environment but also be healthy and affordable. However, there has been little work to assess whether real diets can encompass all three aspects. The aim of this study was to develop a framework to quantify actual diet records for health, affordability and environmental sustainability and apply this to UK food purchase survey data. We applied a Life Cycle Assessment (LCA) approach to detailed food composition data where purchased food items were disaggregated into their components with traceable environmental impact data. This novel approach is an improvement to earlier studies in which sustainability assessments were based on a limited number of “food groups”, with a potentially high variation of actual food items within each group. Living Costs and Food Survey data for 2012, 2013 and 2014 were mapped into published figures for greenhouse gas emissions (GHGE, taking into account processing, transport and cooking) and land use, a diet quality index (DQI) based on dietary guidelines and food cost, all standardised per household member. Households were classified as having a ‘more sustainable’ diet based on GHGE, cost and land use being less than the median and DQI being higher than the median. Only 16.6% of households could be described as more sustainable; this rose to 22% for those in the lowest income quintile. Increasing the DQI criteria to >80% resulted in only 100 households being selected, representing 0.8% of the sample. The framework enabled identification of more sustainable households, providing evidence of how we can move toward better diets in terms of the environment, health, and costs.

Optimizing School Food Supply: Integrating Environmental, Health, Economic, and Cultural Dimensions of Diet Sustainability with Linear Programming

There is great potential for reducing greenhouse gas emissions (GHGE) from public-sector meals. This paper aimed to develop a strategy for reducing GHGE in the Swedish school food supply while ensuring nutritional adequacy, affordability, and cultural acceptability. Amounts, prices and GHGE-values for all foods and drinks supplied to three schools over one year were gathered. The amounts were optimized by linear programming. Four nutritionally adequate models were developed: Model 1 minimized GHGE while constraining the relative deviation (RD) from the observed food supply, Model 2 minimized total RD while imposing stepwise GHGE reductions, Model 3 additionally constrained RD for individual foods to an upper and lower limit, and Model 4 further controlled how pair-wise ratios of 15 food groups could deviate. Models 1 and 2 reduced GHGE by up to 95% but omitted entire food categories or increased the supply of some individual foods by more than 800% and were deemed unfeasible. Model 3 reduced GHGE by up to 60%, excluded no foods, avoided high RDs of individual foods, but resulted in large changes in food-group ratios. Model 4 limited the changes in food-group ratios but resulted in a higher number of foods deviating from the observed supply and limited the potential of reducing GHGE in one school to 20%. Cost was reduced in almost all solutions. An omnivorous, nutritionally adequate, and affordable school food supply with considerably lower GHGE is achievable with moderate changes to the observed food supply; i.e., with Models 3 and 4. Trade-offs will always have to be made between achieving GHGE reductions and preserving similarity to the current supply.

Designing Optimal Breakfast for the United States Using Linear Programming and the NHANES 2011-2014 Database: A Study from the International Breakfast Research Initiative (IBRI)

The quality of dietary patterns can be optimized using a mathematical technique known as linear programming (LP). LP methods have rarely been applied to individual meals. The present LP models optimized the breakfast meal for those participants in the nationally representative National Health and Nutrition Examination Survey 2011-2014 who ate breakfast (n = 11,565). The Nutrient Rich Food Index (NRF9.3) was a measure of diet quality. Breakfasts in the bottom tertile of NRF9.3 scores (T1) were LP-modeled to meet nutrient requirements without deviating too much from current eating habits. Separate LP models were run for children and for adults. The LP-modeled breakfasts resembled the existing ones in the top tertile of NRF9.3 scores (T3), but were more nutrient-rich. Favoring fruit, cereals, and dairy, the LP-modeled breakfasts had less meat, added sugars and fats, but more whole fruit and 100% juices, more whole grains, and more milk and yogurt. LP modeling methods can build on existing dietary patterns to construct food-based dietary guidelines and identify individual meals and/or snacks that need improvement.

Environmental impacts of dietary quality improvement in China

Dietary-related risks rank top among all the health risks in many countries. The 2nd United Nations Sustainable Development Goal aims to end hunger, achieve food security and improved nutrition and promote sustainable agriculture. Yet whether improving nutritional quality also benefits the environment is still under-explored, particularly for developing countries. China is an interesting and important case because of its rapidly changing dietary patterns distinct from the western countries studied in the literature, sub-national level heterogeneity, socio-economic characteristics and lifestyles, as well as its considerable population. This paper evaluates greenhouse gas (GHG) emissions, water consumption, and land appropriation resulting from shifting the Chinese population to healthy diets. We quantify the environmental impacts of individual diets using the latest available data of China Health and Nutrition Survey (2011), and compare them with the environmental impacts of suggested healthy dietary patterns in accordance with the 2016 Chinese Dietary Guidelines. If all Chinese would follow healthy diets rather than their current diets revealed in the survey, GHG emissions, water consumption, and land occupation would increase by 7.5% (63.9 Mt CO₂e annually), 53.5% (510 billion m³), and 54.2% (1256 billion m²), respectively. Urban and high-income groups have higher diet-related environmental impacts but could achieve less additional environmental impacts when moving to healthier diets. These findings indicate an expense of increased GHG emissions, and consumption of water and land resources in improving health. They also highlight the need to focus on the effects of improved economic conditions and urbanization in reconciling environmental impacts and human nutritional adequacy.

Review of Methodologies for Assessing Sustainable Diets and Potential for Development of Harmonised Indicators

The underlying values and priorities that drive policy responses depend largely on the constructs that researchers and decision makers select to measure and the metrics used. Despite much recent attention being given to sustainable diets and food systems and to the importance of clearly measuring sustainability to meet targets, to achieve goals, and to appraise dietary and environmental policies, it is not commonly agreed how the different indicators of sustainable diets are assessed. The evidence base for assessment of these indicators are frequently weak, fragmented, and arbitrary. The aim of this paper was to compare a range of published methods and indicators for assessing sustainable diets and food systems in order to harmonise them. Keyword and reference searches were performed in PubMed, Scopus, CAB Abstracts, and Web of Knowledge. Fifty-two studies (21 proposed methods and 31 used methods) that combined environment, nutrition and health, and socioeconomic aspects of sustainable diets were reviewed. The majority (over 90%) of the studies focused on high-income countries. Twenty-eight studies assessed the environmental effects of different dietary practices, eight of the studies examined the nutrition and health indicators used for assessing sustainable food systems, and seven studies assessed the social and economic costs of diets. A classification of the elements was developed, and common elements are proposed for standardizing. These elements were categorized into nutrition and health indicators, environment indicators, and socioeconomic indicators. Standardized or harmonized indicators can be used for consistency and applicability purposes and to support, implement, and monitor relevant policies.

Carbon footprint of self-selected US diets: nutritional, demographic, and behavioral correlates

BACKGROUND

A substantial portion of greenhouse gas emissions (GHGE) has been attributed to the food sector, but little is known about the association between the carbon footprint of individual self-selected diets in the United States and nutritional quality.

OBJECTIVES

The aims of this study were to assess the GHGE from individual self-selected diets in the United States and examine their association with nutritional quality of the diets, demographic patterns, and food-related behaviors.

METHODS

The dietary GHGE from US adults (>18 y, N = 16,800) in the 2005-2010 National Health and Nutrition Examination Survey (NHANES) were calculated by linking all foods consumed in their 24-h recall diets to our new database of food environmental impacts. Diets were ranked by GHGE/1000 kcal. Those in the top and bottom quintiles were compared on the US Healthy Eating Index (HEI) and on the amounts of specific nutrients known to be under- or overconsumed in the US population. Demographic and behavioral variables from the NHANES were also correlated to these dietary carbon footprints.

RESULTS

Diets in the bottom quintile accounted for one-fifth the total emissions (GHGE/1000 kcal) of those in the top quintile, yet had significantly higher (P < 0.001) HEI scores by 2.3 ± 0.7 points on a 100-point scale. These low-GHGE diets contained higher amounts of fiber and vitamin E and lower amounts of sodium and saturated fats, whereas high-GHGE diets contained higher amounts of vitamins A and D, choline, calcium, iron, and potassium. Low-GHGE diets had less meat, dairy, and solid fats, and more poultry, plant protein foods, oils, whole and refined grains, and added sugars.

CONCLUSIONS

Food patterns responsible for lower GHGE had a better overall diet quality and were more nutritious on several key dimensions, although not all. These results can inform dietary guidance and other policies that seek to address the goals of improved dietary intakes and reduced food-related emissions.

Healthy and sustainable diets that meet greenhouse gas emission reduction targets and are affordable for different income groups in the UK

OBJECTIVE

To model dietary changes required to shift the UK population to diets that meet dietary recommendations for health, have lower greenhouse gas emissions (GHGE) and are affordable for different income groups.

DESIGN

Linear programming was used to create diets that meet dietary requirements for health and reduced GHGE (57 and 80 % targets) by income quintile, taking account of food budgets and foods currently purchased, thereby keeping dietary change to a minimum.Setting/ParticipantsNutrient composition, GHGE and price data were mapped to 101 food groups in household food purchase data (UK Living Cost and Food Survey (2013), 5144 households).

RESULTS

Current diets of all income quintiles had similar total GHGE, but the source of GHGE differed by types of meat and amount of fruit and vegetables. It was possible to create diets with a 57 % reduction in GHGE that met dietary and cost restraints in all income groups. In the optimised diets, the food sources of GHGE differed by income group due to the cost and keeping the level of deviation from current diets to a minimum. Broadly, the changes needed were similar across all groups; reducing animal-based products and increasing plant-based foods but varied by specific foods.

CONCLUSIONS

Healthy and lower-GHGE diets could be created in all income quintiles but tailoring changes to income groups to minimise deviation may make dietary changes more achievable. Specific attention must be given to make interventions and policies appropriate for all income groups.

FFQ versus repeated 24-h recalls for estimating diet-related environmental impact

BACKGROUND

There is an increasing interest in estimating environmental impact of individuals' diets by using individual-level food consumption data. However, like assessment of nutrient intakes, these data are prone to substantial measurement errors dependent on the method of dietary assessment, and this often result in attenuation of associations.

PURPOSE

To investigate the performance of a food frequency questionnaire (FFQ) for estimating the environmental impact of the diet as compared to independent 24-h recalls (24hR), and to study the association between environmental impact and dietary quality for the FFQ and 24hR.

METHODS

We analysed cross-sectional data from 1169 men and women, aged 20-76 years, who participated in the NQplus study, the Netherlands. They completed a 216-item FFQ and two replicates of web-based 24hR. Life cycle assessments of 207 food products were used to calculate greenhouse gas emissions, fossil energy and land use, summarised into an aggregated score, pReCiPe. Validity of the FFQ was evaluated against 24hRs using correlation coefficients and attenuation coefficients. Associations with dietary quality were based on Dutch Healthy Diet 15-index (DHD15-index) and Nutrient Rich Diet score (NRD9.3).

RESULTS

For pReCiPe, correlation coefficient between FFQ and 24hR was 0.33 when adjusted for covariates age, gender and BMI, and increased to 0.76 when de-attenuated for within-subject variation in the 24hR. Energy-adjustment slightly reduced these correlations (r = 0.71 for residuals of observed values and 0.59 for residuals of density values). Covariate-adjusted attenuation coefficient for the FFQ was 0.56 (ʎ₁ = 0.56 and ʎ₁ = 0.65 for observed and density residuals), slightly lower than without covariate adjustment. Diet-related environmental impact was inversely associated with the food-based DHD15-index for both FFQ and 24hR, while associations with the nutrient-based NRD9.3 were inconsistent.

CONCLUSIONS

The FFQ slightly underestimated environmental impact when compared to 24hR. Associations with dietary quality are highly dependent on the diet score used, and less dependent on the method of dietary assessment.

Plant-Based Diets: Considerations for Environmental Impact, Protein Quality, and Exercise Performance

Plant-based diets provide well-established physical and environmental health benefits. These benefits stem in part from the degree of restriction of animal-derived foods. Historically, meat and other animal-derived proteins have been viewed as an integral component of athletes' diets, leading some to question the adequacy of vegetarian or vegan diets for supporting athletic performance. The purpose of this review is to examine the impact of plant-based diets on human physical health, environmental sustainability, and exercise performance capacity. Based on currently available literature, it is unlikely that plant-based diets provide advantages, but do not suffer from disadvantages, compared to omnivorous diets for strength, anaerobic, or aerobic exercise performance. However, plant-based diets typically reduce the risk of developing numerous chronic diseases over the lifespan and require fewer natural resources for production compared to meat-containing diets. As such, plant-based diets appear to be viable options for adequately supporting athletic performance while concurrently contributing to overall physical and environmental health. Given the sparse literature comparing omnivore, vegetarian, and vegan athletes, particularly at the elite level, further research is warranted to ascertain differences that might appear at the highest levels of training and athletic performance.

Mathematical Optimization to Explore Tomorrow's Sustainable Diets: A Narrative Review

A sustainable diet is, by definition, nutritionally adequate, economically affordable, culturally acceptable, and environmentally respectful. Designing such a diet has to integrate different dimensions of diet sustainability that may not be compatible with each other. Among multicriteria assessment methods, diet optimization is a whole-diet approach that simultaneously combines several metrics for dimensions of diet sustainability. This narrative review based on 67 published studies shows how mathematical diet optimization can help with understanding the relations between the different dimensions of diet sustainability and how it can be properly used to identify sustainable diets. Diet optimization aims to find the optimal combination of foods for a population, a subpopulation, or an individual that fulfills a set of constraints while minimizing or maximizing an objective function. In the studies reviewed, diet optimization was used to examine the links between dimensions of diet sustainability, identify the minimum cost or environmental impact of a nutritionally adequate diet, or identify food combinations able to combine ≥2 sustainability dimensions. If some constraints prove difficult to fulfill, this signals an incompatibility between nutrient recommendations, over-monotonous food-consumption patterns, an inadequate supply of nutrient-rich foods, or an incompatibility with other dimensions. If diet optimization proves successful, it can serve to design nutritionally adequate, culturally acceptable, economically affordable, and environmentally friendly diets. Diet optimization results can help define dietary recommendations, tackle food security issues, and promote sustainable dietary patterns. This review emphasizes the importance of carefully choosing the model parameters (variables, objective function, constraints) and input data and the need for appropriate expertise to correctly interpret and communicate the results. Future research should make improvements in the choice of metrics used to assess each aspect of a sustainable diet, especially the cultural dimension, to improve the practicability of the results.

Greenhouse gas emissions of self-selected diets in the UK and their association with diet quality: is energy under-reporting a problem?

BACKGROUND

While the admittedly limited number of epidemiological findings on the association between diet-related greenhouse gas emissions (GHGE) and diet quality are not always consistent, potential influence of bias in the estimation of diet-related GHGE caused by misreporting of energy intake (EI) has not been investigated. This cross-sectional study evaluated diet-related GHGE in the UK and their association with diet quality, taking account of EI under-reporting.

METHODS

Dietary data used were from the National Diet and Nutrition Survey rolling programme 2008/2009-2013/2014, in which 4-day food diaries were collected from 3502 adults aged ≥19 years. Diet-related GHGE were estimated based on 133 food groups, using GHGE values from various secondary sources. Diet quality was assessed by the healthy diet indicator (HDI), Mediterranean diet score (MDS) and Dietary Approaches to Stop Hypertension (DASH) score. EI misreporting was assessed as reported EI divided by estimated energy requirement (EI:EER).

RESULTS

Mean value of daily GHGE was 5.7 kg carbon dioxide equivalents (CO₂eq), which is consistent with those reported from a number of national representative samples in other European countries. Mean EI:EER was 0.74. Assuming that all the dietary variables were misreported in proportion to the misreporting of EI, the mean value of the misreporting-adjusted diet-related GHGE was 8.2 kg CO₂eq/d. In the entire population, after adjustment for potential confounders (i.e., age, sex, ethnicity, socioeconomic classification, smoking status and physical activity), diet-related GHGE were inversely associated with HDI and DASH score but not with MDS. However, with further adjustment for EI:EER, diet-related GHGE showed inverse associations with all three measures of diet quality. Similar associations were observed when only under-reporters (EI:EER < 0.70; n = 1578) were analysed. Conversely, in the analysis including only plausible reporters (EI:EER 0.70-1.43; n = 1895), diet-related GHGE showed inverse associations with all diet quality measures irrespective of adjustment.

CONCLUSIONS

With taking account of EI under-reporting, this study showed inverse associations between diet-related GHGE and diet quality not only in the entire sample but also in the separate analyses of plausible reporters and under-reporters, as well as potential underreporting of diet-related GHGE.