Achieving dietary recommendations and reducing greenhouse gas emissions: modelling diets to minimise the change from current intakes

Many strategies enabling us to optimize kidney care may also be planet-friendly

Kidney replacement therapy (KRT) is one of the most energy-consuming and waste-producing medical treatments. Reducing the need of dialysis is therefore an environmentally friendly choice. However, preferring prevention, lifestyle-related interventions and patient education to drugs is time consuming and most physicians are already overburdened by the many demands of routine clinical practice. In this mini review, we discuss the role that could be played by prevention, diet and non-pharmacological interventions in reducing the impact of care of chronic kidney disease and KRT. Although evaluating the environmental impact of CKD and KRT is extremely complicated, the need for rethinking all the steps in current nephrology practice to preserve our planet's health is urgent, and shifting from a "drug prescription" model to a "time prescription" one would benefit both our patients and the environment.

Seafood supply mapping reveals production and consumption mismatches and large dietary nutrient losses through exports in the United Kingdom

Seafood can contribute towards healthy and sustainable food systems by improving public health and helping achieve net zero carbon emissions. Here, we provide a high-resolution perspective on UK seafood supplies and nutrient flows at the species level. We mapped seafood production (capture and aquaculture), trade (imports and exports), purchases (within and out of home) and seafood consumption between 2009 and 2020. UK dietary recommendations for finfish consumption were not achieved by domestic production nor national supplies. Mapping dietary nutrient flows revealed that the UK undergoes substantial losses of omega-3 fatty acids, vitamin B12 and vitamin D, which could contribute 73%, 46% and 7% towards UK-recommended nutrient intakes, respectively, through exports of oily fish such as salmon, herring and mackerel. Policies should consider promoting greater consumption of locally produced oily fish species to improve public health and seafood system resilience.

What factors influence sustainable and healthy diet consumption? A review and synthesis of literature within the university setting and beyond

Globally, typical dietary patterns are neither healthy nor sustainable. Recognizing the key role of dietary change in reducing noncommunicable disease risk and addressing environmental degradation, it is crucial to understand how to shift individuals toward a sustainable and healthy diet (SHD). In this literature review, we introduced the concept of a SHD and outlined the dietary behaviors necessary to transition toward SHD consumption; we reviewed the literature on factors that may influence sustainable (and unsustainable) dietary behaviors in adults; and we developed a novel scoring system to rank factors by priority for targeting in future research. Given the significant potential to promote a sustainable and healthy dietary transition on the university campus-where factors that may impact dietary behaviors can be targeted at all levels of influence (i.e., individual, interpersonal, environmental, policy)-we narrowed our focus to this setting throughout. Aided by our novel scoring system, we identified conscious habitual eating, product price, food availability/accessibility, product convenience, self-regulation skills, knowledge of animal ethics/welfare, food promotion, and eating norms as important modifiable factors that may influence university students' dietary behaviors. When scored without consideration for the university population, these factors were also ranked as highest priority, as was modified portion sizes. Our findings offer insight into factors that may warrant attention in future research aimed at promoting SHDs. In particular, the high-priority factors identified from our synthesis of the literature could help guide the development of more personalized dietary behavioral interventions within the university setting and beyond.

Impact of consuming an environmentally protective diet on micronutrients: a systematic literature review

BACKGROUND

A global move toward consumption of diets from sustainable sources is required to protect planetary health. As this dietary transition will result in greater reliance on plant-based protein sources, the impact on micronutrient (MN) intakes and status is unknown.

OBJECTIVE

Evaluate the evidence of effects on intakes and status of selected MNs resulting from changes in dietary intakes to reduce environmental impact. Selected MNs of public health concern were vitamins A, D, and B12, folate, calcium, iron, iodine, and zinc.

METHODS

We systematically searched 7 databases from January 2011 to October 2022 and followed the PRISMA guidelines. Eligible studies had to report individual MN intake and/or status data collected in free-living individuals from the year 2000 onward and environmental outcomes.

RESULTS

From the 10,965 studies identified, 56 studies were included, mostly from high-income countries (n = 49). Iron (all 56) and iodine (n = 20) were the most and least reported MNs, respectively. There was one randomized controlled trial (RCT) that also provided the only biomarker data, 10 dietary intake studies, and 45 dietary modeling studies, including 29 diet optimization studies. Most studies sought to reduce greenhouse gas emissions or intake of animal-sourced foods. Most results suggested that intakes of zinc, calcium, iodine, and vitamins B12, A, and D would decrease, and total iron and folate would increase in a dietary transition to reduce environmental impacts. Risk of inadequate intakes of zinc, calcium, vitamins A, B12 and D were more likely to increase in the 10 studies that reported nutrient adequacy. Diet optimization (n = 29) demonstrated that meeting nutritional and environmental targets is technically feasible, although acceptability is not guaranteed.

CONCLUSIONS

Lower intakes and status of MNs of public health concern are a potential outcome of dietary changes to reduce environmental impacts. Adequate consideration of context and nutritional requirements is required to develop evidence-based recommendations. This study was registered prospectively with PROSPERO (CRD42021239713).

Developing a novel optimisation approach for keeping heterogeneous diets healthy and within planetary boundaries for climate change

BACKGROUND AND OBJECTIVES

Current dietary habits have substantial negative impacts on the health of people and the planet. This study aimed to develop a novel approach for achieving health-promoting and climate-friendly dietary recommendations for a broad range of consumers.

SUBJECTS AND METHODS

Hierarchical clustering analysis was combined with linear programming to design nutritionally adequate, health-promoting, climate-friendly and culturally acceptable diets using Swedish national dietary data (n = 1797). Diets were optimised for the average consumption of the total population as well as for the dietary clusters.

RESULTS

Three dietary clusters were identified. All optimised diets had lower shares of animal-source foods and contained higher amounts of plant-based foods. These dietary shifts reduced climate impacts by up to 53% while leaving much of the diet unchanged. The optimised diets of the three clusters differed from the optimised diet of the total population. All optimised diets differed considerably from the food-group pattern of the EAT-Lancet diet.

CONCLUSIONS

The novel cluster-based optimisation approach was able to generate alternatives that may be more acceptable and realistic for a sustainable diet across different groups in the population.

Select dietary changes towards sustainability: Impacts on dietary profiles, environmental footprint, and cost

Healthy sustainable diets have the power to improve dietary intakes and environmental resource use. However, recommendations for improving food choices need to consider the effects of any changes across multiple dimensions of health, environmental sustainability, and dietary cost to promote long-lasting behaviour change. The aim of this study was to identify differences between original diets, and the diets that can be achieved through the implementation of select small dietary changes towards sustainability. Twelve hypothetical sustainable actions were investigated for the potential effects of these actions on dietary markers (protein, saturated fat, sugars, salt, iron, and calcium), environmental footprints (greenhouse gas emissions, freshwater withdrawals, and land use), and dietary cost. Dietary data from 1235 individuals, aged 19-94 years, participating in the UK National Diet and Nutrition Survey (2017/19) provided the original diet. Dietary changes were implemented as required by each sustainable action, and differences between the original diet and each new diet were investigated. Results revealed benefits to dietary markers and environmental characteristics from eleven sustainable actions (range: F(1,728) = 5.80, p < .001 to F(1,506) = 435.04, p < .001), but effects were stronger for some actions than for others. Greatest benefits for all three outcomes were found for actions which reduced meat consumption and/or replaced meat with pulses or eggs. The remaining sustainable actions tended to be beneficial for improving outcomes individually or to some degree. Our results demonstrate the possible impacts of a number of small sustainable dietary actions for dietary, environmental, and cost outcomes, and provide a hierarchy of actions based on benefit. Findings may facilitate dietary behaviours towards improved health, whilst also offering fruitful contributions towards environmental footprint targets in the UK.

Exploring healthy and climate-friendly diets for Danish adults: an optimization study using quadratic programming

Background

A transition to healthy and sustainable diets has the potential to improve human and planetary health but diets need to meet requirements for nutritional adequacy, health, environmental targets, and be acceptable to consumers.

Objective

The objective of this study was to derive a nutritionally adequate and healthy diet that has the least deviation possible from the average observed diet of Danish adults while aiming for a greenhouse gas emission (GHGE) reduction of 31%, corresponding to the GHGE level of the Danish plant-rich diet, which lays the foundation for the current healthy and sustainable food-based dietary guidelines (FBDGs) in Denmark.

Methods

With an objective function minimizing the departure from the average observed diet of Danish adults, four diet optimizations were run using quadratic programming, with different combinations of diet constraints: (1) nutrients only (Nutri), (2) nutrients and health-based targets for food amounts (NutriHealth), (3) GHGE only (GHGE), and finally, (4) combined nutrient, health and GHGE constraints (NutriHealthGHGE).

Results

The GHGE of the four optimized diets were 3.93 kg CO₂-eq (Nutri), 3.77 kg CO₂-eq (NutriHealth) and 3.01 kg CO₂-eq (GHGE and NutriHealthGHGE), compared to 4.37 kg CO₂-eq in the observed diet. The proportion of energy from animal-based foods was 21%-25% in the optimized diets compared to 34% in the observed diet and 18% in the Danish plant-rich diet. Moreover, compared to the average Danish diet, the NutriHealthGHGE diet contained more grains and starches (44 E% vs. 28 E%), nuts (+230%), fatty fish (+89%), eggs (+47%); less cheese (-73%), animal-based fats (-76%), total meat (-42%); and very limited amounts of ruminant meat, soft drinks, and alcoholic beverages (all-90%), while the amounts of legumes and seeds were unchanged. On average, the mathematically optimized NutriHealthGHGE diet showed a smaller deviation from the average Danish diet compared to the Danish plant-rich diet (38% vs. 169%, respectively).

Conclusion

The final optimized diet presented in this study represents an alternative way of composing a nutritionally adequate and healthy diet that has the same estimated GHGE as a diet consistent with the climate-friendly FBDGs in Denmark. As this optimized diet may be more acceptable for some consumers, it might help to facilitate the transition toward more healthy and sustainable diets in the Danish population.

Climate-friendly, health-promoting, and culturally acceptable diets for German adult omnivores, pescatarians, vegetarians, and vegans - a linear programming approach

OBJECTIVES

A frequently suggested approach to reduce greenhouse gas emissions (GHGEs) caused by food production is to reduce the intake of animal products, which can create nutritional deficiencies. This study aimed to identify culturally acceptable nutritional solutions for German adults that are both climate friendly and health promoting.

METHODS

Linear programming was applied to optimize the food supply for omnivores, pescatarians, vegetarians, and vegans considering nutritional adequacy, health promotion, GHGEs, affordability, and cultural acceptability by approaching German national food consumption.

RESULTS

Implementing dietary reference values and omitting meat (products) reduced the GHGEs by ≤52%. The vegan diet was alone in staying below the Intergovernmental Panel on Climate Change (IPCC) threshold of 1.6 kg carbon dioxide equivalents per person per day. The optimized omnivorous diet constrained to meet this goal maintained ≥50% of each baseline food and, on average, deviated from baseline by 36% for women and 64% for men. Butter, milk, meat products, and cheese were reduced by half for both sexes, whereas bread, bakery goods, milk, and meat were reduced mainly for men. The intake of vegetables, cereals, pulses, mushrooms, and fish increased by between 63% and 260% for the omnivores, compared with baseline. Besides the vegan dietary pattern, all optimized diets cost less than the baseline diet.

CONCLUSIONS

A linear programming approach for optimizing the German habitual diet to be healthy, affordable, and meet the IPCC GHGE threshold was possible for several dietary patterns and appears to be a feasible way forward toward including climate goals into food-based dietary guidelines.

Exploring culturally acceptable, nutritious, affordable and low climatic impact diet for Japanese diets: proof of concept of applying a new modelling approach using data envelopment analysis

A future sustainable dietary pattern for Japanese is yet undefined. This study aimed to explore more sustainable Japanese diets that are nutritious, affordable and with low greenhouse gas emissions (GHGE) and particular emphasis on cultural acceptability. A newly developed data envelopment analysis (DEA) diet model was applied to 4-d dietary record data among 184 healthy Japanese men and 185 women volunteers aged 21-69 years. Alternative diets were calculated as the linear combinations of observed diets. Firstly, for each individual, four modelled diets were calculated that maximised cultural acceptability (i.e. minimise dietary change from observed diet), maximised nutritional quality assessed by the Nutrient-Rich Food Index (NRF), minimised monetary diet costs or minimised diet-related GHGE. The final modelled diet combined all four indicators. In the first four models, the largest improvement was obtained for each targeted indicator separately, while relatively small improvements or unwanted changes were observed for other indicator. When all indicators were aimed to optimise, the NRF score and diet-related GHGE were improved by 8-13 % with the lower monetary cost than observed diets, although the percentage improvement was a bit smaller than the separate models. The final modelled diets demanded increased intakes for whole grains, fruits, milk/cream/yogurt, legumes/nuts, and decreased intakes for red and processed meat, sugar/confectioneries, alcoholic and sweetened beverages, and seasonings in both sexes. In conclusion, more sustainable dietary patterns considering several indicators are possible for Japanese, while total improvement is moderate due to trade-offs between indicators and methodological limitation of DEA diet model.

A comparative analysis of sustainability of the usual food intakes of the Iranian population, Iranian food-based dietary guidelines, and optimized dietary models

Promoting sustainable diets might contribute toward achieving sustainable development goals. Considering the importance of national food-based dietary guidelines (FBDGs), this study aimed to assess and compare the sustainability dimensions of the usual Iranian dietary intakes with sustainable optimal diets based on Iranian (2006 and 2015 versions), Mediterranean, and vegetarian FBDGs. The usual dietary intakes of Iranian households were estimated using household expenditure survey data. Diet sustainability, including environmental (water, carbon, and land) footprints, cost, and nutrient-rich food (NRF) index, was calculated for the usual diet and compared with those of different FBDGs. Using linear and goal programming, optimal food models were calculated by minimizing environmental footprints and cost and maximizing NRF simultaneously for each FBDG, while maintaining nutritional considerations recommended by the FBDGs. Replacing the usual dietary intake of Iranians with the optimal diet based on the 2016 Iranian FBDG was associated with reductions equal to 20.9% for water footprint, 22.48% for carbon footprint, 20.39% for land footprint, 31.83% for cost, and 7.64% increase in NRF index. The optimal model based on the 2016 Iran FBDG was 10% more sustainable compared with the 2005 version. Changing the usual consumption of Iranians to the optimal model based on the Mediterranean pyramid was accompanied by the highest NRF index, lower environmental footprints, and cost compared to other models. The recent Iranian FBDG, compared with the older one, was more sustainable. Considering the dimensions of a sustainable diet for future FBDG revisions is recommended.

Healthy and Sustainable Food Shopping: A Survey of Intentions and Motivations

Objectives

To determine the relationship between sustainable and healthy food shopping behavior comparing general motivation with the immediate intention to act.

Method

We conducted an online survey of 144 staff at the Cork Institute of Technology, Ireland, using a questionnaire based on the Theory of Planned Behavior and the Self-Determination Theory to compute the Behavioral Intention score and the Relative Autonomy Index in relation to healthy and sustainable grocery shopping.

Results

The intention to shop healthy food was higher (p &lt; 0.001, Cohen's d = 0.56) than the intention to shop in a sustainable way. A significant intention-action gap was observed for both healthy (p &lt; 0.001, Cohen's d = 0.97) and sustainable grocery shopping (p &lt; 0.001, Cohen's d = 1.78). While there was a significant correlation (p &lt; 0.001) between the longer-term motivations to act in a healthy and sustainable way, this association was not significant (p = 0.16) for the more short-term Behavioral Intention scores.

Conclusion and Implications

Health was identified as a more important driver for dietary behavior compared to sustainability. While longer-term motivation shows a stronger correlation between healthy and sustainable grocery shopping, short-term intentions do not follow this pattern as strongly. A significant intention-action gap exists for both, which is stronger for sustainability than for health.

Individual Diet Optimization in French Adults Shows That Plant-Based “Dairy-like” Products May Complement Dairy in Sustainable Diets

This study aimed to explore the potential role of plant-based “dairy-like” products (PBDL) in sustainable diets. For each individual from a representative sample of French adults (INCA2 survey 2006–2007; n = 1816), a diet optimized to be more sustainable (nutritionally adequate while having a 30% reduced carbon impact with minimal change from the actual diet and isocaloric content) was modelled. The food content of the optimized diets was compared to actual diets, with a focus on PBDL and dairy products. The presented quantitative results focused on women. Optimized diets contained more plant-based products and less meats than actual diets. PBDL products were present in 7.3% and 55.7% of the subjects’ actual and optimized diets, respectively, increasing significantly from 7 to 48 g/day. Regarding dairy products, cheese decreased (−14 g/day), milk increased (+14 g/day), and yogurt remained constant (87 g/day) between the actual and optimized diets, such that the intake of this food group remained constant (214 g/day). Women for whom PBDL products were introduced as new foods in their optimized diets were found to be those with actual low energy intake (1755 kcal/d on average). As a complement to dairy products, fortified PBDL products may help to achieve more sustainable diets, especially for individuals with low energy intakes.

Perspective: Striking a Balance between Planetary and Human Health: Is There a Path Forward?

The global adoption of predominantly plant-based sustainable healthy diets will help reduce the risk of obesity- and malnutrition-related non-communicable diseases while protecting the future health of our planet. This review examines the benefits and limitations of different types of plant-based diets in terms of health and nutrition, affordability and accessibility, cultural (ethical and religious) acceptability, and the environment (i.e., the four pillars underlying sustainable healthy diets). Results suggest that, without professional supervision, traditional plant-based diets (vegan, vegetarian and pescatarian diets) can increase the risk of nutritional deficiencies among infants, children/adolescents, adult females, pregnant/lactating women and the elderly. In contrast, flexitarian diets and territorial diversified diets (TDDs, e.g., Mediterranean and New Nordic diets) that include large quantities of plant-sourced foods, low levels of red meat and moderate amounts of poultry, fish, eggs and dairy can meet the energy and nutrition needs of different populations without the need for dietary education or supplementation. Compared to vegan, vegetarian and pescatarian diets, more diverse flexitarian diets and TDDs are associated with reduced volumes of food waste and may be more acceptable and easier to maintain for people who previously followed western diets. Although flexitarian diets and TDDs have a greater impact on the environment than vegan, vegetarian and pescatarian diets, the negative effects are considerably reduced compared to western diets, especially if diets include locally-sourced seasonal foods. Further studies are required to define more precisely optimal sustainable healthy diets for different populations and to ensure that diets are affordable and accessible to people in all countries.

Assessing consumers' attitudes, expectations and intentions towards health and sustainability regarding seafood consumption in Italy

The EU and its Member States have articulated a sustainability vision 'to live well within the limits of our planet' by 2050. In this context, consumers play a key role, being able to drive seafood production sustainability and responsibility according to their behaviour, also in relation to their attitudes towards health, nutrition and well-being. On the basis of these premises, this research explores Italian consumers' attitudes towards health and sustainability in relation to seafood, in order to segment different target of consumers. The framework used in this study is mainly focused on a quantitative exploratory data collection based on an online survey. Three groups of consumers were identified based on general health interest, perceived benefits of eating seafoods and attitude towards seafoods: Health seekers who eat seafood for duty; Health seekers and seafood lovers; Low commitment to health and indifferent to seafood. Differences among groups related to socio-demographic characteristics, sustainability attitudes, intentions and interest in information about seafood products were also investigated. In particular, the first two groups are more familiar with sustainable seafood products and more interested in information on these products than the third, both in terms of product origin and seasonality. Consumers belonging to second group show a higher probability to buy seafood products considering this characteristic than the other two groups. Based on the results obtained, a strategic plan could be developed to achieve relevant goals in education, communication and sustainability labelling related with seafood products. Following a preliminary scouting carried out with all the seafood stakeholders, a specific territory to test this approach has been already identified in Torre del Cerrano (Italy). These results have a strong implication for policy makers and educational institutions as they identify differences in attitudes and perceptions among consumers that are crucial in order to design the right communication strategy strategies as well as messages content.

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

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

Cost and greenhouse gas emissions of current, healthy, flexitarian and vegan diets in Aotearoa (New Zealand)

Objective

To compare the costs and climate impact (greenhouse gas emissions) associated with current and healthy diets and two healthy and environmentally friendly dietary patterns: flexitarian and vegan.

Design

Modelling study

Setting

Aotearoa (New Zealand).

Main outcome measures

The distribution of the cost and climate impact (kgCO₂e/kg of food per fortnight) of 2 weekly current, healthy, vegan and flexitarian household diets was modelled using a list of commonly consumed foods, a set of quantity/serves constraints for each, and constraints for food group and nutrient intakes based on dietary guidelines (Eating and Activity Guidelines for healthy diets and EAT-Lancet reference diet for vegan and flexitarian diets) or nutrition survey data (current diets).

Results

The iterative creation of 210–237 household dietary intakes for each dietary scenario was achieved using computer software adapted for the purpose (DIETCOST). There were stepwise differences between diet scenarios (p<0.001) with the current diet having the lowest mean cost in New Zealand Dollars (NZ$584 (95% CI NZ$580 to NZ$588)) per fortnight for a family of four) but highest mean climate impact (597 kgCO₂e (95% CI 590 to 604 kgCO₂e)), followed by the healthy diet (NZ$637 (95% CI NZ$632 to NZ$642), 452 kgCO₂e (95% CI 446 to 458 kgCO₂e)), the flexitarian diet (NZ$728 (95% CI NZ$723 to NZ$734), 263 kgCO₂e (95% CI 261 to 265 kgCO₂e)) and the vegan diet, which had the highest mean cost and lowest mean climate impact (NZ$789, (95% CI NZ$784 to NZ$794), 203 kgCO₂e (95% CI 201 to 204 kgCO₂e)). There was a negative relationship between cost and climate impact across diets and a positive relationship within diets.

Conclusions

Moving from current diets towards sustainable healthy diets (SHDs) will reduce climate impact but generally at a higher cost to households. The results reflect trade-offs, with the larger constraints placed on diets, the greater cost and factors such as nutritional adequacy, variety, cost and low-emissions foods being considered. Further monitoring and policies are needed to support population transitions that are country specific from current diets to SHD.

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 Promotion of Sustainable Diets in the Healthcare System and Implications for Health Professionals: A Scoping Review

The impacts of the current global food system are already visible in the environment and in the health of the population. The promotion of sustainable diets is key to counter the negative consequences. The healthcare system could be a powerful tool to educate patients by guiding their diets towards sustainability. This study aimed to assess the size and scope of the available literature regarding the promotion of sustainable diets in the healthcare system and to obtain a reliable approximation of the processes and roles related to sustainable diet promotion within healthcare systems. A scoping review where online databases were used to identify English written scientific and grey literature published between 2000-2019 was carried out. The analytical-synthetic approach was used for data charting. Twelve studies were included that were published between 2007-2020. The data highlight education, community and clinical health services, community engagement and policy advocacy, and governance as main action areas along with two transversal aspects, social support, and gender. A systemic approach to the food system is emphasized. Evidence suggests that health professionals have the potential to drive a paradigm shift in food-health environments. Currently, however, their role and potential impact is underestimated within healthcare systems. This review has identified a framework with key areas where processes need to be developed to guarantee sustainable diet promotion in healthcare services.

Climate Change, Food Supply, and Dietary Guidelines

Food production is affected by climate change, and, in turn, food production is responsible for 20-30% of greenhouse gases. The food system must increase output as the population increases and must meet nutrition and health needs while simultaneously assisting in achieving the Sustainable Development Goals. Good nutrition is important for combatting infection, reducing child mortality, and controlling obesity and chronic disease throughout the life course. Dietary guidelines provide advice for a healthy diet, and the main principles are now well established and compatible with sustainable development. Climate change will have a significant effect on food supply; however, with political commitment and substantial investment, projected improvements will be sufficient to provide food for the healthy diets needed to achieve the Sustainable Development Goals. Some changes will need to be made to food production, nutrient content will need monitoring, and more equitable distribution is required to meet the dietary guidelines. Increased breastfeeding rates will improve infant and adult health while helping to reduce greenhouse gases.

A cross-sectional survey of the readiness of consumers to adopt an environmentally sustainable diet

BACKGROUND

The current food system is responsible for significant environmental damage therefore, encouraging consumers to adopt an environmentally sustainable diet is a key public health challenge. Dietary guidelines have been developed that outline recommendations for purchasing and consuming food in an environmentally sustainable manner, but they have not yet been incorporated in UK national dietary guidelines.

METHODS

Via an online survey of UK adults, we evaluated consumers' perceptions of the environmental benefit of various sustainable diet recommendations, their readiness to adopt these behaviours using the stage of change construct of the Transtheoretical Model, the factors that influenced their food choices, and their current consumption of plant- and animal-based sources of protein. Additionally, we investigated how demographic characteristics and food choice motives were associated with perceived environmental benefit of and readiness to adopt these sustainable diet recommendations.

RESULTS

The survey was completed by 442 participants (66% female, 80% aged 25-54 years, 85% with higher education). The majority of participants considered the recommendations to 'reduce consumption of air-freighted foods' (79%), 'reduce food waste' (75%), and 'buy locally grown produce' (78%) to have a high environmental benefit, whereas a smaller proportion of participants perceived 'prioritise plant-based proteins' (42%) and 'choose organic produce' (27%) to have a high environmental benefit. Differences in perceptions and readiness to adopt sustainable dietary behaviours were observed between demographic groups, with women significantly more likely than men to be in action/maintenance (A/M) stages of change for prioritising plant proteins (OR 0.54), and younger participants more likely to be in pre-contemplation/contemplation (PC/C) stages of change for 'choose organic produce' (OR 2.03) and 'choose sustainable fish' (OR 2.45). Health, cost, environmental sustainability and taste were the most commonly reported food choice motives. Reporting environmental sustainability as a food choice motive was associated with readiness to adopt sustainable diet recommendations.

CONCLUSIONS

We found that consumers in the UK are engaged with some aspects of sustainable diets but remain resistant to others. The results of this study indicate that acceptable dietary guidelines could be developed to address environmental sustainability. Several behaviours were identified that consumers were willing to adopt, but there were barriers preventing them, highlighting that policy action is required to enable behaviour change to occur. Differences between demographic groups highlight potential targets for future campaigns promoting sustainable diets.

Integration of various dimensions in food-based dietary guidelines via mathematical approaches: report of a DGE/FENS Workshop in Bonn, Germany, 23-24 September 2019

In the past, food-based dietary guidelines (FBDGs) were derived nearly exclusively by using systematic reviews on diet-health relationships and translating dietary reference values for nutrient intake into foods. This approach neglects many other implications that dietary recommendations have on society, the economy and environment. In view of pressing challenges, such as climate change and the rising burden of diet-related diseases, the simultaneous integration of evidence-based findings from different dimensions into FBDGs is required. Consequently, mathematical methods and data processing are evolving as powerful tools in nutritional sciences. The possibilities and reasons for the derivation of FBDGs via mathematical approaches were the subject of a joint workshop hosted by the German Nutrition Society (DGE) and the Federation of European Nutrition Societies (FENS) in September 2019 in Bonn, Germany. European scientists were invited to discuss and exchange on the topics of mathematical optimisation for the development of FBDGs and different approaches to integrate various dimensions into FBDGs. We concluded that mathematical optimisation is a suitable tool to formulate FBDGs finding trade-offs between conflicting goals and taking several dimensions into account. We identified a lack of evidence for the extent to which constraints and weights for different dimensions are set and the challenge to compile diverse data that suit the demands of optimisation models. We also found that individualisation via mathematical optimisation is one perspective of FBDGs to increase consumer acceptance, but the application of mathematical optimisation for population-based and individual FBDGs requires more experience and evaluation for further improvements.

Improving health and carbon footprints of European diets using a benchmarking approach

OBJECTIVE

This study aimed to identify diets with improved nutrient quality and environmental impact within the boundaries of dietary practices.

DESIGN

We used Data Envelopment Analysis to benchmark diets for improved adherence to food-based dietary guidelines (FBDG). We then optimised these diets for dietary preferences, nutrient quality and environmental impact. Diets were evaluated using the Nutrient Rich Diet score (NRD15.3), diet-related greenhouse gas emission (GHGE) and a diet similarity index that quantified the proportion of food intake that remained similar as compared with the observed diet.

SETTING

National dietary surveys of four European countries (Denmark, Czech Republic, Italy and France).

SUBJECTS

Approximately 6500 adults, aged 18-64 years.

RESULTS

When dietary preferences were prioritised, NRD15·3 was ~6 % higher, GHGE was ~4 % lower and ~85 % of food intake remained similar. This diet had higher amounts of fruit, vegetables and whole grains than the observed diet. When nutrient quality was prioritised, NRD15·3 was ~16 % higher, GHGE was ~3 % lower and ~72 % of food intake remained similar. This diet had higher amounts of legumes and fish and lower amounts of sweetened and alcoholic beverages. Finally, when environmental impact was prioritised, NRD15·3 was ~9 % higher, GHGE was ~21 % lower and ~73 % of food intake remained similar. In this diet, red and processed meat partly shifted to either eggs, poultry, fish or dairy.

CONCLUSIONS

Benchmark modelling can generate diets with improved adherence to FBDG within the boundaries of dietary practices, but fully maximising health and minimising GHGE cannot be achieved simultaneously.

How to protect both health and food system sustainability? A holistic 'global health'-based approach via the 3V rule proposal

OBJECTIVE

To define a generic diet to protect human health and food system sustainability based on three dimensions: animal:plant ratio, degree of food processing and food diversity.

DESIGN/SETTING

The percentages of maximum animal and ultra-processed energy content were evaluated from scientific papers (Web of Science database) and reports from international scientific institutions. Then, a weekly French standard diet, including these percentages and food diversity (≥42 different foods), was designed to calculate adequacy to nutritional needs.

RESULTS

Based on traditional and scientifically based healthy diets, and on foresight scenarios for sustainable diets at horizon 2050, a median daily animal energy content intake of 15 % was found to be protective towards both human health and environment. Based on epidemiological studies associating ultra-processed energy consumption with increased overweight/obesity risk, a precautionary threshold of approximately 15 % ultra-processed energy content was observed. The French diet allows addressing all nutritional needs and other nutritional indicators such as maximum salt and simple sugar consumption, α-linolenic acid:linoleic acid ratio and essential amino acids. This diet was named the '3V rule' for Végétal (plant), Vrai (real) and Varié (varied, if possible organic, local and seasonal). This generic diet can be adapted according to regional traditions and environmental characteristics. Excluding only one dimension of it would threaten both health and food system sustainability.

CONCLUSIONS

Tending towards a 3V-based diet, while respecting local constraints, should allow preserving human health, environment (greenhouse gas emissions, pollution, deforestation, etc.), small farmers, animal welfare and biodiversity, culinary traditions and socioeconomics (including an alleviation of public health cost).

Replacing the nutrients in dairy foods with non-dairy foods will increase cost, energy intake and require large amounts of food: National Health and Nutrition Examination Survey 2011-2014

Objective:

The US Dietary Guidelines for Americans recommends increased consumption of the dairy group to three daily servings for ages 9+ years to help achieve adequate intakes of prominent shortfall nutrients. Identifying affordable, consumer-acceptable foods to replace dairy’s shortfall nutrients is important especially for people who avoid dairy.

Design:

Linear programming identified food combinations to replace dairy’s protein and shortfall nutrients. We examined cost, energy and dietary implications of replacing dairy with food combinations optimised for lowest cost, fewest kJ or the smallest amount of food by weight.

Setting:

National Health and Nutrition Examination Survey (2011–2014).

Participants:

Nationally representative sample of US population; 2 years and older (n 15 830).

Results:

Phase 1 (only dairy foods excluded): when optimised for lowest cost or fewest kJ, all non-dairy food replacements required large amounts (2·5–10 cups) of bottled/tap water. Phase 2 (dairy and unreasonable non-dairy foods excluded (e.g. baby foods; tap/bottled water): when intake of non-dairy foods was constrained to <90th percentile of current intake, the lowest cost food combination replacements for dairy cost 0·5 times more and provide 5·7 times more energy; the lowest energy food combinations cost 5·9 times more, provide 2·5 times more energy and require twice the amount of food by weight; and food combinations providing the smallest amount of food by weight cost 3·5 times more and provide five times more energy than dairy.

Conclusions:

Identifying affordable, consumer-acceptable foods that can replace dairy’s shortfall nutrients at both current and recommended dairy intakes remains a challenge.

Review of sustainable diets: are nutritional objectives and low-carbon-emission objectives compatible?

Food systems in developed countries face one major challenge, namely the promotion of diets that are both healthy and generate less greenhouse gas emissions (GHGE). In this article, we review papers evaluating the impact of a change in diets on both health and GHGE. We address the following questions: How big are the health and environmental impacts that could be induced by a switch to healthier diets? In monetary value, what is the relative importance of the health impact and the environmental impact? Is it possible to design an economic policy to increase global welfare that also takes into account the externalities on both health and the environment? Since the way the change in diet is modeled is a key issue, we classify papers according to the methodology used for simulating diet changes: ad hoc scenarios, optimized diets, and economic modeling. We find that it is possible to design economic policies that have positive impacts on both dimension. Because the substitutions/complementarities between food products are complex, it is not granted that a policy targeting one dimension will generate positive effects on the other dimensions. However, given the diversity of substitution and the complementarity possibilities between products, it is possible to design a policy that does improve both dimensions. A carbon-based tax policy that targets the products with a high greenhouse gas content (e.g., meat products) and reinvests the revenues collected with the tax to subsidize the consumption of fruit and vegetables, is likely to have positive effects on both dimensions.

Sustainable and acceptable school meals through optimization analysis: an intervention study

Background

School meals hold considerable potential to shape children’s diets and reduce food-related greenhouse gas emissions (GHGE)—in the short and long term. This study applied linear optimization to develop a GHGE-reduced, nutritionally adequate, and affordable school lunch menu. The effects on food waste, consumption and pupils’ satisfaction with the meals were evaluated.

Methods

A pre-post design was employed to assess the effects of implementing an optimized lunch menu on daily food waste, consumption, and pupils’ school meal satisfaction in three schools (grades 0–9) from one Swedish municipality. A food list containing amounts, prices, nutrient content, and GHGE-values of all foods used for a previously served (baseline) four-week lunch menu was created. Using linear programming, this food list was optimized for minimum deviation and constrained to ensure nutritional adequacy and a reduced climate impact. The optimized food list was developed into a new (intervention) four-week lunch menu by a professional meal planner, following the baseline menu as closely as possible. The baseline and intervention menus were served for four weeks, respectively, with a two week break in between. Prepared, wasted and leftover food were weighed daily by the school kitchen staff during both periods. Interrupted time series analysis assessed mean and slope differences in daily food waste and consumption between the two periods. School lunch satisfaction was assessed with an online questionnaire at baseline and during the intervention.

Results

Optimization resulted in a food list that was 40% lower in GHGE, met all nutrient recommendations for school meals, and cost 11% less compared to baseline. The intervention menu was served as planned, with only minor changes required (for practical reasons). Plate waste, serving waste, consumption and school lunch satisfaction did not differ significantly from baseline, in any of the schools.

Conclusions

The findings demonstrate that school meals can successfully be improved regarding health and environmental sustainability using linear optimization, without negative effects on food waste, consumption or cost. This approach offers the necessary flexibility to tailor menus towards different priorities and could therefore be transferred to other types of meal services.

Trial registration

The trial is registered at clinicaltrials.gov (NCT04168632 Fostering Healthy and Sustainable Diets Through School Meals (OPTIMAT).

Could Dietary Goals and Climate Change Mitigation Be Achieved Through Optimized Diet? The Experience of Modeling the National Food Consumption Data in Italy

Objective: The aim of this study is to define a healthy and sustainable diet model with low GHGE, fulfilling dietary requirements, and considering current Italian food consumption patterns. Design: A duly designed database was developed, linking food nutritional composition and GHGE based on 921 food items consumed in Italy according to the last national food consumption survey (INRAN-SCAI 2005-2006). Linear programming was used to develop new diet plans separately for males and females, aged 18-60 years (n = 2,098 subjects), in order to minimize GHGE. The program is based on dietary goals and acceptability constraints as well as on 13 nutrient requirement constraints aiming to reach a healthy and acceptable diet for the Italian population. Results: Diet optimization resulted in a nutritionally adequate pattern minimizing GHGE values (4.0 vs. 1.9 kg CO2e/day for males and 3.2 vs. 1.6 kg CO2e/day for females). In both sexes, the nutrient intake of the optimized diet was at the established lower bound for cholesterol and calcium and at the established upper bound for free sugar and fiber. In males, intake of zinc was at the established lower bound whereas iron was at the established upper bound. Consumption of red meat and fruit and vegetables was at the established lower and upper bound, respectively, in both males and females. Despite the decrease in meat consumption, especially red meat, in the optimized diet with respect to the observed diet, levels of iron intake in females increased by 10% (10.3 vs. 11.3 mg/day) but remained below the adequate intake established in Italian national DRIs. Conclusions: An attainable healthy dietary pattern was developed that would lead to the reduction of GHGE by 48% for males and by 50% for females with respect to current food consumption in the Italian adult population. Health-promoting dietary patterns can substantially contribute to achieve related Sustainable Development Goals.

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).

Alimentação saudável e sustentável: uma revisão narrativa sobre desafios e perspectivas

Resumo Parte-se do princípio que um sistema alimentar insustentável não é capaz de produzir alimentos saudáveis para o consumo. A alimentação só pode ser considerada saudável se for também sustentável, devendo ultrapassar a perspectiva nutricional. Assim, realizou-se uma revisão narrativa de literatura acerca de sistemas alimentares saudáveis e sustentáveis, englobando aspectos de produção, processamento, comercialização e consumo, visando levantar seus desafios e perspectivas de consolidação. A alimentação saudável e sustentável deve estar relacionada à produção de alimentos que protejam a biodiversidade e promovam o consumo variado, resgatando alimentos, preparações e hábitos culturais tradicionais. Deve ser acessível e disponível a todos, em quantidade e qualidade, baseada em alimentos produzidos e processados na região, por agricultores familiares, de maneira agroecológica, fundamentada na comercialização justa, aproximando a produção do consumo. Além disso, deve ser isento de contaminantes físicos, biológicos ou químicos que causem malefícios a todos os envolvidos, de maneira aguda ou crônica.

Climate impact from diet in relation to background and sociodemographic characteristics in the Västerbotten Intervention Programme

OBJECTIVE

The objective of this study was to examine climate impact from diet across background and sociodemographic characteristics in a population-based cohort in northern Sweden.

DESIGN

A cross-sectional study within the Västerbotten Intervention Programme. Dietary data from a 64-item food frequency questionnaire collected during 1996-2016 were used. Energy-adjusted greenhouse gas emissions (GHGE) for all participants, expressed as kg carbon dioxide equivalents/day and 4184 kJ (1000 kcal), were estimated using data from life cycle analyses. Differences in background and sociodemographic characteristics were examined between participants with low and high GHGE from diet, respectively. The variables evaluated were age, BMI, physical activity, marital status, level of education, smoking, and residence.

SETTING

Västerbotten county in northern Sweden.

PARTICIPANTS

In total, 46 893 women and 45 766 men aged 29-65 years.

RESULTS

Differences in GHGE from diet were found across the majority of examined variables. The strongest associations were found between GHGE from diet and age, BMI, education, and residence (all P < 0·001), with the highest GHGE from diet found among women and men who were younger, had a higher BMI, higher educational level, and lived in urban areas.

CONCLUSIONS

This study is one of the first to examine climate impact from diet across background and sociodemographic characteristics. The results show that climate impact from diet is associated with age, BMI, residence and educational level amongst men and women in Västerbotten, Sweden. These results define potential target populations where public health interventions addressing a move towards more climate-friendly food choices and reduced climate impact from diet could be most effective.

The Willingness to Modify Portion Sizes or Eat New Protein Foods Largely Depends on the Dietary Pattern of Protein Intake

Promoting a more balanced animal/plant dietary protein ratio by changing portion sizes or introducing new foods is a promising means to improve diet quality, but little is known about the willingness of individuals to adopt such changes. Our objective was to assess the willingness to adopt dietary changes by these means. In a French cross-sectional study in 2018 (n = 2055), we analyzed the association between the willingness to eat smaller or larger portions or to introduce non-consumed protein foods and the current dietary patterns of individuals and their socio-demographic characteristics. These modifications had previously been identified as improving the nutrient adequacy of diets. Participants were more willing to eat smaller portion sizes than to introduce new foods and to eat larger portion sizes. The willingness for any modification varied depending on the food groups concerned. Participants were also more willing to eat larger portions and less willing to eat smaller portions when they were the most frequent consumers of the foods concerned. Participants were more willing to eat a new food if it was consumed in large quantities by individuals with a similar dietary pattern. This study underlines the importance of accounting for individual food habits when issuing nutritional recommendations.

Optimising healthy and safe fish intake recommendations: a trade-off between personal preference and cost

Individuals may perceive personalised dietary advice as more relevant and motivational than national guidelines. Personal preference and food cost are factors that can affect consumer decisions. The objective of this study was to present a method for modelling and analysing the trade-off between deviation from preference and food cost for optimised personalised dietary recommendations. Quadratic programming was applied to minimise deviation from fish preference and cost simultaneously with different weights on the cost for 3016 Danish adults (whose dietary intake and body weight were recorded in a national dietary survey). Model constraints included recommendations for EPA, DHA and vitamin D and tolerable levels for methyl mercury, dioxins and dioxin-like polychlorinated biphenyls. When only minimising deviation from preference, 50 % of the study population should be recommended to increase fish intake, 48 % should be suggested to maintain current consumption and 2 % should be suggested to decrease fish consumption. When only minimising cost, the vast majority (99 %) should be recommended to only consume herring, which is the least-expensive fish species. By minimising deviation from preference and cost simultaneously with different weights on the cost, personalised optimal trade-off curves between deviation from fish intake preference and fish cost could be generated for each individual in our study population, except for twenty-two individuals (0·7 %) whose contaminant background exposure was too high. In the future, the method of this paper could be applied in the personal communication of healthy and safe food recommendations that fit the preferences of individual consumers.

Exploring the Relationship between Environmental Impact and Nutrient Content of Sandwiches and Beverages Available in Cafés in a UK University

The threat of climate change and population growth has led to calls for the adoption of environmentally sustainable diets; however, concerns have been raised over the nutritional quality of low Greenhouse Gas Emission (GHGE) diets. This study examined the relationship between measures of environmental sustainability and nutrient content of sandwiches and beverages sold in a UK university café. GHGE and Water Footprint Impact Indicator (WFII) values for the ingredients of sandwiches and beverages were used with recipe information to calculate GHGE (gCO2e per portion) and WFIIs (scarcity weighted litres per portion). These estimates were then combined via orthogonal regression to produce a single Environmental Impact Score (EIS); higher scores equate to greater environmental impact. The relationship between EIS and nutrient content was explored using correlation analysis. Sandwiches that contained meat and animal products as well as beverages that contained milk, cocoa, and/or coffee had the highest EIS. EIS was positively associated with the portion size of sandwiches but not the serving size of beverages. EIS was positively correlated with calories, saturated fat, and sodium. However, EIS was also positively correlated with micronutrients: iron, calcium (beverages only), and B12 (beverages only). The choice of smaller or plant-based sandwiches as well as beverages without milk would reduce environmental impact as well as caloric and sodium intake. However, the selection of low impact options may also reduce the intake of nutrients required for good health. This study revealed possible tensions between nutritional quality and environmental sustainability.

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.

Nutrition from a climate change perspective

Climate change is threatening future global food and nutrition security. Limiting the increase in global temperature to 1·5 °C set out in The Paris Agreement (2015) while achieving nutrient security means overhauling the current food system to create one that can deliver healthy and sustainable diets. To attain this, it is critical to understand the implications for nutrition of actions to mitigate climate change as well as the impacts of climate change on food production and the nutrient composition of foods. It is widely recognised that livestock production has a much greater environmental burden than crop production, and therefore advice is to reduce meat consumption. This has triggered concern in some sectors about a lack of protein in diets, which hence is driving efforts to find protein replacements. However, in most high- and middle-income countries, protein intakes far exceed dietary requirements and it would even if all meat were removed from diets. Reduction in micronutrients should be given more attention when reducing meat. Simply eating less meat does not guarantee healthier or more sustainable diets. Climate change will also affect the type, amount and nutrient quality of food that can be produced. Studies have shown that increased temperature and elevated CO2 levels can reduce the nutrient density of some staple crops, which is of particular concern in low-income countries. Nutrition from a climate change perspective means considering the potential consequences of any climate action on food and nutrition security. In this paper, we discuss these issues from an interdisciplinary perspective.

Searching for a Measure Integrating Sustainable and Healthy Eating Behaviors

Sustainable and healthy food-related behavior is high on the public policy and research agenda due to its potential to cope with negative environmental and health outcomes. There are several measures related to sustainability in food choices but there have not been many attempts to integrate sustainable and healthy eating (SHE) behaviors into one measurement instrument so far. Therefore, the main aim of this study was to identify how young adults interpret the SHE concept and to develop an instrument that measures a self-reported consumer's SHE behavior. The process of scale development involved an exploratory qualitative study and two quantitative studies. As a result of 20 individual in depth interviews with Polish young adults, 50 items were generated reflecting their perspective on principles of SHE (Study 1). Two samples were used in the scale validation process: n = 217 (Study 2) and n = 220 (Study 3). Via principal component analysis, reliability analysis, and confirmatory factor analysis, the final form of the scale was derived. The proposed 34-item scale offers insights into the most relevant aspects of SHE behaviors, grouped in eight factors: "healthy and balanced diet", "certification and quality labels", "meat reduction", "selection of local food", "choice of low fat food products", "avoidance of food waste" and purchase and consumption of food products that are respecting "animal welfare" and finally choice of "seasonal food". Although the developed scale can benefit from further refinement and validity testing in different cultural and social background, it is clear that the scale, as developed, can be a useful tool for researchers who are interested in the study of SHE behaviors.

Sociodemographic Variation in Consumption Patterns of Sustainable and Nutritious Seafood in Australia

National dietary guidelines (DGs) consistently recommend consuming seafood for health benefits, however, the sustainability of increasing seafood consumption is often challenged. Seafood products vary in environmental performance as well as health benefits, yet there is no information integrating the health and ecological impacts of different seafood choices. The first step in optimising improved health and environmental outcomes is to examine more closely the types of seafood being consumed at population and individual levels, to develop the means to increase the intake of seafood that is optimal for human health and the environment. The purpose of this analysis was to better understand the specific types and amounts of seafood consumed by the Australian population, and by socioeconomic subgroups within the population, to determine the relative nutritional content and sustainability of seafood consumed by these groups. Secondary analysis of the Australian Health Survey (AHS) (2011-2013), which reached 32,000 people (25,000 households) was undertaken. The majority of respondents (83%) did not consume any seafood on the day of the survey. Results indicated the proportion of seafood consumers was lowest among adults who were unemployed, had the least education and were the most socio-economically disadvantaged. Crustaceans and farmed fish with low omega 3-content, such as basa and tilapia, were identified as the least nutritious and least sustainable seafood categories. These two categories constituted a substantial amount of total seafood intake for the lowest socio-economic consumers, and over 50% for unemployed consumers. In contrast, consumers in the highest socio-demographic group consumed mainly high trophic level fish (moderate nutrition and sustainability) and farmed fish with high omega-3 content (high nutrition, moderate sustainability). Fewer than 1% of adults or children reported eating seafood identified as both more nutritious and less resource intensive, such as small pelagics or molluscs. Opportunities exist to increase seafood intakes to improve health outcomes by varying current seafood consumption patterns to maximise nutritional outcomes and minimise environmental impacts. Initiatives to promote the health and environmental benefits of seafood should be promoted at the population level, with targeted interventions for specific groups, and should encourage consumption of highly nutritious low resource intensive types of seafood.

Translation of nutrient recommendations into personalized optimal diets for Chinese urban lactating women by linear programming models

Background

Lactating women need to consume a high-quality diet to replete nutrient stores depleted during pregnancy and to ensure sufficient nutrition for breastfeeding. However, several studies reported suboptimal dietary quality and nutrient intake of lactating mothers in China. The objectives of this study was to apply dietary modeling method to develop individualized optimal diets, which meet the nutrient requirements for lactating women in urban China.

Methods

Data were collected from a sample of 576 lactating women from 0 to 240 days postpartum during the Maternal Infant Nutrition Growth study conducted between 2011 and 2012 in three cities including Beijing, Guangzhou, and Suzhou. Dietary intake data were collected with an interviewer-administered 24-h survey. Linear programming was applied to develop dietary plans that meet recommendations for lactation women in the China Dietary Reference Intakes 2013 and the Chinese Dietary Guideline 2016, while with least deviation from the observed dietary intake.

Results

Through dietary modeling, individual optimal diets were developed for 576 lactating women. The optimal diets met all the food and nutrient intake constraints set in the linear programming models. The large difference between observed and optimized diets suggests that the nutrient needs of lactating mothers in China may only be met after substantial dietary changes. In addition, the analysis showed that it was difficult to meet the recommended intake for six nutrients: vitamin A, vitamin B1, vitamin B6, calcium, selenium, and dietary fiber. Moreover, four clusters in the optimized diets were identified by K-means cluster analysis. The four clusters confirmed that the optimal diets developed by linear programming could characterize the variety in dietary habits by geographical regions and duration of lactation.

Conclusion

Linear programming could help translate nutrient recommendations into personal diet advices for a sample of urban lactating mothers from China. The study showed that dietary modeling is helpful to support healthy eating of lactation women by translating dietary guidelines into personalized meal plans.

Trial registration

The Maternal Infant Nutrition Growth study was registered in ClinicalTrials.gov with identifier NCT01971671. Registration date October 29, 2013.

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.

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.

A Review of the Use of Linear Programming to Optimize Diets, Nutritiously, Economically and Environmentally

The "Diet Problem" (the search of a low-cost diet that would meet the nutritional needs of a US Army soldier) is characterized by a long history, whereas most solutions for comparable diet problems were developed in 2000 or later, during which computers with large calculation capacities became widely available and linear programming (LP) tools were developed. Based on the selected literature (52 papers), LP can be applied to a variety of diet problems, from food aid, national food programmes, and dietary guidelines to individual issues. This review describes the developments in the search for constraints. After nutritional constraints, costs constraints, acceptability constraints and ecological constraints were introduced. The 12 studies that apply ecological constraints were analyzed and compared in detail. Most studies have used nutritional constraints and cost constraints in the analysis of dietary problems and solutions, but such research begin showing weaknesses under situations featuring a small number of food items and/or nutritional constraints. Introducing acceptability constraints is recommended, but no study has provided the ultimate solution to calculating acceptability. Future possibilities lie in finding LP solutions for diets by combining nutritional, costs, ecological and acceptability constraints. LP is an important tool for environmental optimization and shows considerable potential as an instrument for finding solutions to a variety of very complex diet problems.

Reducing GHG emissions while improving diet quality: exploring the potential of reduced meat, cheese and alcoholic and soft drinks consumption at specific moments during the day

Background

The typical Western diet is associated with high levels of greenhouse gas (GHG) emissions and with obesity and other diet-related diseases. This study aims to determine the impact of adjustments to the current diet at specific moments of food consumption, to lower GHG emissions and improve diet quality.

Methods

Food consumption in the Netherlands was assessed by two non-consecutive 24-h recalls for adults aged 19–69 years (n = 2102). GHG emission of food consumption was evaluated with the use of life cycle assessments. The population was stratified by gender and according to tertiles of dietary GHG emission. Scenarios were developed to lower GHG emissions of people in the highest tertile of dietary GHG emission; 1) reducing red and processed meat consumed during dinner by 50% and 75%, 2) replacing 50% and 100% of alcoholic and soft drinks (including fruit and vegetable juice and mineral water) by tap water, 3) replacing cheese consumed in between meals by plant-based alternatives and 4) two combinations of these scenarios. Effects on GHG emission as well as nutrient content of the diet were assessed.

Results

The mean habitual daily dietary GHG emission in the highest tertile of dietary GHG emission was 6.7 kg CO₂-equivalents for men and 5.1 kg CO₂-equivalents for women. The scenarios with reduced meat consumption and/or replacement of all alcoholic and soft drinks were most successful in reducing dietary GHG emissions (ranging from − 15% to − 34%) and also reduced saturated fatty acid intake and/or sugar intake. Both types of scenarios lead to reduced energy and iron intakes. Protein intake remained adequate.

Conclusions

Reducing the consumption of red and processed meat during dinner and of soft and alcoholic drinks throughout the day leads to significantly lower dietary GHG emissions of people in the Netherlands in the highest tertile of dietary GHG emissions, while also having health benefits. For subgroups of the population not meeting energy or iron requirements as a result of these dietary changes, low GHG emission and nutritious replacement foods might be needed in order to meet energy and iron requirements.

Integrating nutrient bioavailability and co-production links when identifying sustainable diets: How low should we reduce meat consumption?

Background

Reducing the consumption of meat and other animal-based products is widely advocated to improve the sustainability of diets in high-income countries. However, such reduction may impair nutritional adequacy, since the bioavailability of key nutrients is higher when they come from animal- vs plant-based foods. Meat reduction may also affect the balance between foods co-produced within the same animal production system.

Objective

The objective was to assess the impact of introducing nutrient bioavailability and co-production links considerations on the dietary changes needed − especially regarding meat ‒ to improve diet sustainability.

Methods

Diet optimization with linear and non-linear programming was used to design, for each gender, three modeled diets departing the least from the mean observed French diet (OBS) while reducing by at least 30% the diet-related environmental impacts (greenhouse gas emissions, eutrophication, acidification): i) in the nutrition-environment (NE) model, the fulfillment of recommended dietary allowances for all nutrients was imposed; ii) in the NE-bioavailability (NEB) model, nutritional adequacy was further ensured by accounting for iron, zinc, protein and provitamin A bioavailability; iii) in the NEB-co-production (NEB-CP) model, two links between co-produced animal foods (milk–beef and blood sausage–pork) were additionally included into the models by proportionally co-constraining their respective quantities. The price and environmental impacts of individual foods were assumed to be constant.

Results

‘Fruit and vegetables’ and ‘Starches’ quantities increased in all modeled diets compared to OBS. In parallel, total meat and ruminant meat quantities decreased. Starting from 110g/d women’s OBS diet (168g/d for men), total meat quantity decreased by 78%, 67% and 32% for women (68%, 66% and 62% for men) in NE, NEB and NEB-CP diets, respectively. Starting from 36g/d women’s OBS diet (54g/d for men), ruminant meat quantity dropped severely by 84% and 87% in NE and NEB diets for women (80% and 78% for men), whereas it only decreased by 27% in NEB-CP diets (38% for men). The share of energy and proteins of animal origin was similar for the 3 modeled diets (approximately 1/5 of total energy, and 1/2 of protein) and lower than in OBS diet (approximately 1/3 of total energy, and 2/3 of protein).

Conclusions

Decreasing meat content was strictly needed to achieve more sustainable diets for French adults, but the reduction was less severe when nutrient bioavailability and co-production links were taken into account.