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

High reliance on fortified foods when optimizing diets of adolescents in Sweden for adequate vitamin D intake and climate sustainability

The global food system contributes roughly one-third of global greenhouse gas emissions (GHGEs) making shifts towards more sustainable food consumption an imperative. Such diets also need to factor in nutrient requirements and cultural acceptability. Our aim was to simulate dietary changes for adolescents in Sweden to achieve the recommended intake (RI) for vitamin D while factoring in additional nutrients, cultural acceptability and keeping the diet within planetary boundaries for climate change. A baseline diet was estimated from Sweden's national dietary survey Riksmaten Adolescents 2016-17 (n = 3099, ages 11-18 years), which provided food intake via two 24-hour recalls. Intake data were linked to the Swedish Food Agency's food composition database and GHGE estimates from the Research Institutes of Sweden's (RISE) Food Climate Database. Linear programming was used to optimize the baseline diet to meet the RI for vitamin D (10 µg/day), reduce GHGEs to ≤ 1.7 kg CO2-equivalents/person/day, and minimize dietary changes from baseline to factor in cultural acceptability. A second optimization included 25 additional nutrients requirements. Both optimized diets met their respective requirements reducing GHGEs by 54 % but relied heavily on milk and yoghurt (fortified by law), which provided > 60 % of vitamin D intake. Both diets also required major shifts toward plant-based foods and the second optimization demanded a five-fold greater change in diet from baseline compared to first optimization. Results suggest that adolescents in Sweden can achieve RIs for vitamin D and other nutrients while greatly reducing diet-related GHGEs, though cultural acceptability may be a challenge.

A methodological framework for deriving the German food-based dietary guidelines 2024: Food groups, nutrient goals, and objective functions

BACKGROUND

For a growing number of food-based dietary guidelines (FBDGs), diet optimization is the tool of choice to account for the complex demands of healthy and sustainable diets. However, decisions about such optimization models' parameters are rarely reported nor systematically studied.

OBJECTIVES

The objectives were to develop a framework for (i) the formulation of decision variables based on a hierarchical food classification system; (ii) the mathematical form of the objective function; and (iii) approaches to incorporate nutrient goals.

METHODS

To answer objective (i), food groups from FoodEx2 levels 3-7 were applied as decision variables in a model using acceptability constraints (5th and 95th percentile for food intakes of German adults (n = 10,419)) and minimizing the deviation from the average observed dietary intakes. Building upon, to answer objectives (ii) and (iii), twelve models were run using decision variables from FoodEx2 level 3 (n = 255), applying either a linear or squared and a relative or absolute way to deviate from observed dietary intakes, and three different lists of nutrient goals (allNUT-DRV, incorporating all nutrient goals; modNUT-DRV excluding nutrients with limited data quality; modNUT-AR using average requirements where applicable instead of recommended intakes).

RESULTS

FoodEx2 food groups proved suitable as diet optimization decision variables. Regarding deviation, the largest differences were between the four different objective function types, e.g., in the linear-relative modNUT-DRV model, 46 food groups of the observed diet were changed to reach the model's goal, in linear-absolute 78 food groups, squared-relative 167, and squared-absolute 248. The nutrient goals were fulfilled in all models, but the number of binding nutrient constraints was highest in the linear-relative models (e.g. allNUT-DRV: 11 vs. 7 in linear-absolute).

CONCLUSION

Considering the various possibilities to operationalize dietary aspects in an optimization model, this study offers valuable contributions to a framework for developing FBDGs via diet optimization.

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.

Acceptability and effect on food choices of incentives promoting more sustainable diets among low-income consumers: A qualitative study

In the context of rising food costs, low-income consumers are likely to lack financial access to a sustainable diet primarily composed of healthy plant-based food. To promote a change towards more sustainable food habits, vouchers for fruit, vegetables and legumes redeemable in supermarkets have been experimented in the urban area of Dijon (France). The objective of the study was to explore the acceptability of the intervention and the effects of the vouchers on food choices through participants' perceptions. Face-to-face semi-structured interviews were conducted with twenty-seven participants, three months after the end of the intervention. The transcripts were analysed through inductive then deductive content analysis, following a process evaluation framework with two themes related to the implementation and the mechanisms of impact of the intervention. Implementation issues and feelings of discrimination were mentioned, but satisfaction was high and vouchers were considered to improve the financial situation, although the restriction on the targeted products was not always understood. Regarding the mechanisms of impact, during the intervention period, two third of the participants, especially families with young children, attached greater importance to taste and curiosity for unfamiliar food and lesser importance to price. Vouchers thus led to food purchases of higher diversity and higher enjoyment. Other participants did not change their habits, mostly because of an improper use of the vouchers or the absence of motivation for a dietary change. These findings suggest that financial incentives not only increase access to sustainable food, but also influence food choice processes and contribute to greater acceptability of plant-based food in low-income families. The results call for financial incentives to be considered as an opportunity to support changes in dietary behaviour in low-income populations.

Environmental trade-offs of meeting nutritional requirements with a lower share of animal protein for adult subpopulations

Decreasing the share of protein contributed by animal-based foods is recommended to move towards more sustainable and healthier diets. This study aimed to assess the potential environmental impacts of diets with a lower share of animal protein. The diets were modeled to include the minimum share of animal protein in total protein that met nutrient requirements and did not increase costs. The new diets also minimized the difference in the quantity of food from those of observed (OBS) diets. They were modeled for five adult subpopulations (defined by sex and age) using mathematical optimization. The model was created by combining the INCA2 database (to model OBS diets in the French population) and a database of 207 food items to adjust nutritional and price parameters. All modeled diets satisfied nutritional and cost constraints. A low-animal-protein (LAP) diet was identified for each subpopulation by progressively decreasing the share of animal protein by steps of 5% until the recommended quantity of protein and/or consumption constraints were no longer satisfied. Potential environmental impacts of the LAP diets in eight impact categories were calculated using life cycle assessment and life cycle inventories from Agribalyse® 3.0. A LAP diet for the entire population was calculated as a weighted mean of the subpopulations' LAP diets. The share of animal protein decreased from 70% in the OBS diet to 50% in the LAP diet. Compared to the OBS diet, the LAP diet decreased five environmental impacts: climate change (greenhouse gas emissions), acidification (emissions of acidifying compounds) and land occupation (all by more than 30%), cumulative energy demand (by 23%) and marine eutrophication (by 13%). Conversely, it increased three environmental impacts: freshwater eutrophication and water use (both by ca. 40%) and biodiversity damage potential (potential loss of species associated with land use) (by 66%). These results suggest that decreasing the share of animal protein to 50% is compatible with nutritional requirements, affordability and consumption constraints, but would have mixed effects on the environment.

Modelling the cost differential between current and healthy diets according to household education level in Belgium

This study aims to estimate the cost differential between current and healthy diets, overall and by household education level. Data from the 2014-2015 Belgian National Food Consumption Survey and food prices from the 2014 GfK ConsumerScan panel were linked. The DIETCOST programme was used to model healthy, isocaloric healthy and current diets. For the reference household, the average daily diet cost was 20.1€ (95%CI: 19.9-20.4) for current diets, 20.9€ (95%CI: 20.6-21.2) for healthy isocaloric diets (+3.9% vs. the current diets) and 22.5€ (95%CI: 22.3-22.8) for healthy diets (+12.0%). In low-educated households, the cost of current and of healthy isocaloric diets was similar (19.2€ (95%CI: 19.0-19.5) vs. 19.3€ (95%CI: 19.0-19.6)), whereas in high-educated households, the cost of healthy isocaloric diets (22.0€; 95%CI: 21.8-22.3) was higher than the cost of current diets (21.2€; 95%CI: 20.9-21.4)). Though needing validation, this finding is valuable for interventions aimed at improving dietary habits in disadvantaged populations.

Can micronutrient requirements be met by diets from sustainable sources: outcomes of dietary modelling studies using diet optimization

BACKGROUND

Consumption of diets from sustainable sources is required for planetary health, however, large sections of the population, including females of reproductive age and children, will be at risk of not meeting their micronutrient (MN) requirements in a complete transition to plant-based foods. Constrained diet optimization methods use mathematical programming to construct diets that meet predefined parameters and may contribute towards modelling dietary solutions that meet nutritional and planetary targets.

OBJECTIVE

Review the evidence from diet optimization studies proposing solutions to ensure MN availability in the context of a transition to diets from sustainable sources.

APPROACH

Narrative review focusing on literature published over the last five years.

RESULTS

Dietary modelling using diet optimization can design a range of omnivorous and plant-based diets that meet individual MN requirements, have reduced environmental impacts, and minimize deviation from culturally acceptable dietary practices. Using data from large-scale dietary surveys, diet optimization can support development of food-based dietary guidelines; identify limiting MNs in a particular context or a conflict between constraints e.g. nutrition and environment; explore food-based strategies to increase nutrient supply, such as fortification; and support trial design. Methods used and outcomes reported are sources of variability. Individual-level dietary data and MN requirements for population sub-groups such as females of reproductive age and children are important requirements. Although maintaining iron and zinc intakes are regularly reported to present challenges in diets from sustainable sources, few studies have considered bioavailability, which reduces with increased dietary phytate. These and other data gaps including acceptability and affordability must be addressed to improve the applicability of modelling outcomes in population recommendations.

CONCLUSIONS

Dietary modelling using diet optimization can be useful in the design of more sustainable diets that meet MN requirements, however, translation of outcomes into dietary intervention studies is required to test real-world application and adoption into dietary guidelines.

Low-carbon diets across diverse dietary patterns: Addressing population heterogeneity under constrained optimization

Mathematical optimization is a useful tool for modeling diets that fulfill requirements for health and environmental sustainability, however, population-based optimization approaches fail to account for underlying dietary diversity in populations. This study proposes a methodological approach to consider diverse dietary intake patterns in mathematical optimization of nutritionally adequate low-carbon diets and investigates the differences between different population groups, along with trade-offs between greenhouse gas emission (GHGE) reduction and the inconvenience of dietary changes required to achieve optimized diets. A k-means clustering analysis was applied to individual dietary intake data from Denmark, which resulted in four clusters with different dietary patterns. This was followed by quadratic programming, wherein the total dietary changes required from the observed diet within each cluster were used as a proxy for consumer inconvenience (i.e., "inconvenience index") and were minimized while fulfilling nutrient constraints and incrementally tightened GHGE constraints. Across clusters, a steep increase of the inconvenience index was observed at GHGE levels below approximately 3 kg CO2e/10 MJ, corresponding to GHGE reductions of 24-36 % in different clusters. In all clusters, the optimized diets with nutritional and GHGE constraints showed common traits of increased content of cereals and starches, eggs, and fish and decreased amounts of beef and lamb, cheese, animal-based fats, and alcoholic beverages, but differences across clusters were also observed, maintaining characteristics of the clusters' baselines. When additional health-based targets for food amounts were applied as constraints, the optimized diets converged towards the same type of diet. The total inconvenience of dietary changes required to fulfill constraints differed between clusters, indicating that specific sub-populations may be more effective targets for dietary transition. The method has potential for future integration of more sustainability aspects and different consumer preferences.

Alignment between greenhouse gas emissions reduction and adherence the EAT-Lancet diet: A modeling study based on the NutriNet-Santé cohort

The potential of the EAT-Lancet reference diet, which promotes a healthy diet within planetary limits, to reduce greenhouse gas emissions (GHGe) remains understudied. This study examines the role of nutritional and acceptability constraints in reducing GHGe through diet optimization, and tests the alignment between GHGe reduction and the EAT-Lancet score. The study used data from 29,413 NutriNet-Santé participants to model French diets and evaluate their environmental, nutritional, economic, and health impact. The Organic Food Frequency Questionnaire was used to assess organic and conventional food consumed, and the Dialecte database was used to estimate the diet environmental impacts. Quality of diets were also evaluated based using the PNNS-GS2 (Programme National Nutrition-Santé 2 guidelines score). When testing minimizing GHGe under strict nutritional and acceptability constraints, it was possible to reduce GHGe up to 67 % (from 4.34 in the observed diet to GHGe = 1.45 kgeqCO2/d) while improving the EAT score by 103 % with 91 % of the food as organic. Greater reductions required relaxation of some constraints. When testing maximizing EAT score under gradual reduction in GHGe, the adherence to the EAT-Lancet diet was not significantly affected by the gradual reduction in GHGe. To maximize EAT score with 75 % reduction in GHGe (1.09 kgeqCO2/d), less strict constraints on the bioavailability of iron and zinc are necessary. The EAT score improved by 141 %, while land occupation decreased by 57 %, compared to the observed value. The diet contained 94 % of organic foods. There was some alignment between the degree of adherence to the EAT-Lancet diet and the reduction in GHGe, but other diets may also lead to a strong reduction in GHGe. Thus, GHGe can be greatly reduced by dietary choices, but require profound reshaping of diets which must be coupled with changes in other areas of the food chain.

Integrating environmental sustainability into food-based dietary guidelines in the Nordic countries

The overall aim of this paper was to provide background knowledge to the Nordic Nutrition Recommendations 2023 Committee for integrating environmental sustainability in a framework for national Food-Based Dietary Guidelines (FBDG) within the Nordics and Baltics. Additionally, this paper aims to give an overview of recent Nordic scientific literature on environmental impact of foods and dietary patterns and of the FBDG of the Nordics. Finally, we suggest methods for developing national sustainable FBDG. Nordic and Baltic studies on sustainability of diets were searched in August 2022 and complemented with additional relevant literature. The studies show that current diets are far from environmentally sustainable, exceeding planetary boundaries for most impact categories; meat and dairy products being the largest contributors to dietary greenhouse gas emissions (GHGEs) and land use. Scenario, modelling, optimisation and intervention studies confirm the potential of shifting towards more plant-based diets to improve overall diet quality in terms of both health and environmental sustainability. Such diets comprised of vegetables, fruits, legumes, potatoes, whole grain and refined cereal products, nuts, seeds and vegetable oils, with animal foods in moderate or limited amounts. The FBDG in the Nordics promotes more plant-based diets than the current average diet but could improve from further integration of environmental sustainability. To form basis for sustainable FBDG dietary modelling at the national level, prioritising health outcomes and nutritional adequacy is essential. Second, integrating environmental sustainability involves estimating the impact of food choices and amounts on GHGE, land and water use, eutrophication and biodiversity loss. Exploring positive and negative implications of fortified foods and supplementation in relation to nutrient intake, health and environmental sustainability may be needed. Implementing dietary transition requires solutions beyond FBDG to ensure affordability, acceptability and ease of adaption.

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.

Moving towards more sustainable diets: Is there potential for a personalised approach in practice?

Discourse on the relationship between food production, healthy eating and sustainability has become increasingly prominent and controversial in recent years. Research groups often take one perspective when reporting on sustainable diets, and several often neglect considerations for the multiple aspects that make a diet truly sustainable, such as cultural acceptability, differences in nutritional requirements amongst the population and the efficiency of long-term dietary change. Plant-based diets are associated with lower greenhouse gas emissions (GHGEs) and have been linked with better health outcomes, including lower risk of diet-related chronic disease. However, foods associated with higher GHGE, such as lean red meat, fish and dairy, have beneficial nutritional profiles and contribute significantly to micronutrient intakes. Some research has shown that diets associated with lower GHGE can be less nutritionally adequate. Several countries now include sustainability recommendations in dietary guidelines but use vague language such as "increase" or "consume regularly" when referring to plant-based foods. General population-based nutrition advice has poor adherence and does not consider differences in nutritional needs. Although modelling studies show potential to significantly reduce environmental impact with dietary changes, personalising such dietary recommendations has not been studied. Adapting recommendations to the individual through reproducible methods of personalised nutrition has been shown to lead to more favourable and longer-lasting dietary changes compared to population-based nutrition advice. When considering sustainable healthy dietary guidelines, personalised feedback may increase the acceptability, effectiveness and nutritional adequacy of the diet. A personalised approach has the potential for delivering a new structure of more sustainable healthy food-based dietary guidelines. This review evaluates the potential to develop personalised sustainable healthy food-based dietary guidelines and discusses potential implications for policy and practice.

Environmental pressures and pesticide exposure associated with an increase in the share of plant-based foods in the diet

Diets rich in plant-based foods are encouraged for human health and to preserve resources and the environment but the nutritional quality and safety of such diets is debated. This study aimed to model nutritionally adequate diets with increasing plant food content and to characterise the derived diets using a multicriteria approach including, nutrients intake, environmental pressures and exposure to pesticides. Using data of the NutriNet-Santé cohort (N = 29,413), we implemented stepwise optimization models to identified maximum plant-food content under nutritional constraints. Environmental indicators at the production level were derived from the DIALECTE database, and exposure to pesticide residues from plant food consumption was estimated using a contamination database. Plant-based foods contributed to 64.3% (SD = 10.6%) of energy intake in observed diets and may reach up to 95% in modelled diets without jeopardizing nutritional status. Compared to the observed situation, an increase in plant-based foods in the diets led to increases in soy-based products (+ 480%), dried fruits (+ 370%), legumes (+ 317%), whole grains (+ 251%), oils (+ 144%) and vegetables (+ 93%). Animal products decreased progressively until total eviction, except for beef (- 98%). Dietary quality (estimated using the Diet Quality Index Based on the Probability of Adequate Nutrient Intake) was improved (up to 17%) as well as GHGe (up to - 65%), energy demand (up to - 48%), and land occupation (- 56%) for production. Exposures to pesticides from plant-based foods were increased by 100% conventional production and to a much lesser extent by 100% organic production. This study shows that shifting to nutritionally-adequate plant-based diets requires an in-depth rearrangement of food groups' consumption but allows a drastic reduction environmental impact. Increase exposure to pesticide residues and related risks can be mitigated by consuming foods produced with low pesticide input.

Improving school lunch menus with multi-objective optimisation: nutrition, cost, consumption and environmental impacts

OBJECTIVE

To support school foods programmes by evaluating the relationship between nutritional quality, cost, student consumption and the environmental impacts of menus.

DESIGN

Using linear programming and data from previously served menu items, the relationships between the nutritional quality, cost, student consumption and the environmental impacts of lunch menus were investigated. Optimised lunch menus with the maximum potential student consumption and nutritional quality and lowest costs and environmental impacts were developed and compared with previously served menus (baseline).

SETTING

Boston Public Schools (BPS), Boston Massachusetts, USA.

PARTICIPANTS

Menu items served on the 2018-2019 BPS lunch menu (n 142).

RESULTS

Using single-objective models, trade-offs were observed between most interests, but the use of multi-objective models minimised these trade-offs. Compared with the current weekly menus offered, multi-objective models increased potential caloric intake by up to 27 % and Healthy Eating Index scores by up to 19 % and reduced costs and environmental impacts by up to 13 % and 71 %, respectively. Improvements were made by reducing the frequency of beef and cheese entrées and increasing the frequency of fish and legume entrées on weekly menus.

CONCLUSIONS

This work can be extrapolated to monthly menus to provide further direction for school districts, and the methods can be employed with different recipes and constraints. Future research should test the implementation of optimised menus in schools and consider the broader implications of implementation.

Metabolic syndrome criteria and severity and carbon dioxide (CO2) emissions in an adult population

BACKGROUND

Metabolic syndrome (MetS) has become a growing risk factor of some non-communicable diseases. Increase of greenhouse gas emissions affects the planet.

AIMS

To assess the association between MetS severity and amount of carbon dioxide (CO₂) emitted in an adult population.

DESIGN

Cross-sectional study (n = 6646; 55-76-year-old-men; 60-75-year-old-women with MetS).

METHODS

Dietary habits were assessed using a pre-validated semi quantitative 143-item food frequency questionnaire. The amount of CO₂ emitted due to the production of food consumed by person and day was calculated using a European database, and the severity of the MetS was calculated with the MetS Severity Score.

RESULTS

Higher glycaemia levels were found in people with higher CO₂ emissions. The risk of having high severe MetS was related to high CO₂ emissions.

CONCLUSIONS

Low CO₂ emissions diet would help to reduce MetS severity. Advantages for both health and the environment were found following a more sustainable diet.

TRIAL REGISTRATION

ISRCTN, ISRCTN89898870 . Registered 05 September 2013.

Consumption of Pulses among Chilean Vegetarians and Non-Vegetarians during the Covid-19 Pandemic

The aim of the present study was to compare the frequency of consumption, access to purchase, and type of preparations with pulses among people who eat a vegetarian/vegan or non-vegetarian diet during the COVID-19 pandemic.

Cross-sectional surveys were distributed using different digital platforms and social networks. We investigated the frequency of consumption, access to purchase any type of preparations. Descriptive analyses were performed. Differences between the types of diet were tested by Chi-squared statistics.

A total of 3339 adults participated in the survey in March 2021, 80% of the total participants were females; 13.6% were vegetarian or vegan (VV). The consumption of pulses increased by 25% among non-vegetarians and 54.5% in VV (p by 25% among non-vegetarians and 54.5% in VV (vey in March 2021, 80% of the total participants were females; 13.6% were vegetarian or vegan (VV). The consumption of pulses preparations. Descriptive analyses were performfood with high satiating power, when compared with the opinions of non-vegetarians (p ood with high satiating power, when cconsumption of pulses were observed in less than 30% of the respondents, but the percentage was lower among VV, the most common negative beliefs are "They are difficult to prepare" and "My family does not like them." Food preparations including pulses are more diverse among VV, and consumption being significantly higher in the 10 alternatives of preparations included in the study.

These results highlight the importance of identifying the knowledge, practices, frequency, and preferences of consumption of legumes in the population to stimulate their consumption. Although we observed an increase in the consumption of legumes among those in the sample, the VV group showed a higher frequency of consumption, consumption of different types of legumes and varied preparation, and greater knowledge about the beneficial properties of legumes.

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.

Plant to animal protein ratio in the diet: nutrient adequacy, long-term health and environmental pressure

Background

Animal and plant protein sources have contrasting relationships with nutrient adequacy and long-term health, and their adequate ratio is highly debated.

Objective

We aimed to explore how the percentage of plant protein in the diet (%PP) relates to nutrient adequacy and long-term health but also to environmental pressures, to determine the adequate and potentially optimal %PP values.

Methods

Observed diets were extracted from the dietary intakes of French adults (INCA3, n = 1,125). Using reference values for nutrients and disease burden risks for foods, we modeled diets with graded %PP values that simultaneously ensure nutrient adequacy, minimize long-term health risks and preserve at best dietary habits. This multi-criteria diet optimization was conducted in a hierarchical manner, giving priority to long-term health over diet proximity, under the constraints of ensuring nutrient adequacy and food cultural acceptability. We explored the tensions between objectives and identified the most critical nutrients and influential constraints by sensitivity analysis. Finally, environmental pressures related to the modeled diets were estimated using the AGRIBALYSE database.

Results

We find that nutrient-adequate diets must fall within the ~15-80% %PP range, a slightly wider range being nevertheless identifiable by waiving the food acceptability constraints. Fully healthy diets, also achieving the minimum-risk exposure levels for both unhealthy and healthy foods, must fall within the 25-70% %PP range. All of these healthy diets were very distant from current typical diet. Those with higher %PP had lower environmental impacts, notably on climate change and land use, while being as far from current diet.

Conclusion

There is no single optimal %PP value when considering only nutrition and health, but high %PP diets are more sustainable. For %PP > 80%, nutrient fortification/supplementation and/or new foods are required.

Environmental and nutritional Life Cycle Assessment of novel foods in meals as transformative food for the future

Sustainable diets are key for mitigating further anthropogenic climate change and meeting future health and sustainability goals globally. Given that current diets need to change significantly, novel/future foods (e.g., insect meal, cultured meat, microalgae, mycoprotein) present options for protein alternatives in future diets with lower total environmental impacts than animal source foods. Comparisons at the more concrete meal level would help consumers better understand the scale of environmental impacts of single meals and substitutability of animal sourced foods with novel foods. Our aim was to compare the environmental impacts of meals including novel/future foods with those of vegan and omnivore meals. We compiled a database on environmental impacts and nutrient composition of novel/future foods and modeled the impacts of calorically similar meals. Additionally, we applied two nutritional Life Cycle Assessment (nLCA) methods to compare the meals in terms of nutritional content and environmental impacts in one index. All meals with novel/future foods had up to 88 % less Global Warming Potential, 83 % less land use, 87 % less scarcity-weighted water use, 95 % less freshwater eutrophication, 78 % less marine eutrophication, and 92 % less terrestrial acidification impacts than similar meals with animal source foods, while still offering the same nutritional value as vegan and omnivore meals. The nLCA indices of most novel/future food meals are similar to protein-rich plant-based alternative meals and show fewer environmental impacts in terms of nutrient richness than most animal source meals. Substituting animal source foods with certain novel/future foods may provide for nutritious meals with substantial environmental benefits for sustainably transforming future food systems.

Measurement of diets that are healthy, environmentally sustainable, affordable, and equitable: A scoping review of metrics, findings, and research gaps

Introduction

Research on the impacts of dietary patterns on human and planetary health is a rapidly growing field. A wide range of metrics, datasets, and analytical techniques has been used to explore the role of dietary choices/constraints in driving greenhouse gas (GHG) emissions, environmental degradation, health and disease outcomes, and the affordability of food baskets. Many argue that each domain is important, but few have tackled all simultaneously in analyzing diet-outcome relationships.

Methods

This paper reviews studies published between January 2015 and December 2021 (inclusive) that examined dietary patterns in relation to at least two of the following four thematic pillars: (i) planetary health, including, climate change, environmental quality, and natural resource impacts, (ii) human health and disease, (iii) economic outcomes, including diet cost/affordability, and (iv) social outcomes, e.g., wages, working conditions, and culturally relevant diets. We systematically screened 2,425 publications by title and abstract and included data from 42 eligible publications in this review.

Results

Most dietary patterns used were statistically estimated or simulated rather than observed. A rising number of studies consider the cost/affordability of dietary scenarios in relation to optimized environmental and health outcomes. However, only six publications incorporate social sustainability outcomes, which represents an under-explored dimension of food system concerns.

Discussion

This review suggests a need for (i) transparency and clarity in datasets used and analytical methods; (ii) explicit integration of indicators and metrics linking social and economic issues to the commonly assessed diet-climate-planetary ecology relationships; (iii) inclusion of data and researchers from low- and middle-income countries; (iv) inclusion of processed food products to reflect the reality of consumer choices globally; and (v) attention to the implications of findings for policymakers. Better understanding is urgently needed on dietary impacts on all relevant human and planetary domains simultaneously.

Higher adherence to the EAT-Lancet reference diet is associated with higher nutrient adequacy in the NutriNet-Santé cohort : a cross-sectional study

BACKGROUND

In 2019, the EAT-Lancet Commission proposed a planetary and healthy reference diet; however, its nutritional quality has been rarely evaluated.

OBJECTIVE

Across different adherence levels to the EAT-Lancet reference diet, the following were our objectives:1) describe the food and nutritional intakes of the French population, 2) to evaluate the nutrient quality and, 3) investigate the consistency between the French national recommendations and the EAT-Lancet reference diet.

DESIGN

This cross-sectional study was conducted among participants of the NutriNet-Santé cohort and the sample was weighted on the characteristics of the general French population. Adherence to the EAT-Lancet reference diet was estimated using the EAT-Lancet Diet Index (ELD-I). Usual nutrient intakes were obtained using the variance reduction method. We used the estimated average requirements cut-point method to estimate the proportion of participants who meet their respective nutritional requirements. Furthermore, the adequacy of the French food-based dietary recommendations (Programme National Nutrition Santé [PNNS]) according to adherence to the EAT-Lancet reference diet was studied.

RESULTS

The weighted sample was composed of 98,465 participants. Except for bioavailable zinc and vitamin B12, we observed a decrease in the nutrient inadequacy prevalence when the adherence to the EAT-Lancet reference diet increased, particularly for vitamin B9 (Q1=37.8% vs. Q5=5.5%, p=<0.0001) and vitamin C (Q1=59.0% vs. Q5=10.8 %, p=<0.0001). However, inadequacy prevalence remained high in all ELD-I quintiles, particularly for fiber (95.9%), vitamin B1 (70.8%), iodine (48.4%), and magnesium (76.8%). Higher ELD-I score was associated with higher adherence for most components of the PNNS, except for food groups that are not specifically included in the EAT-Lancet reference diet and are typical of the French diet, including alcohol, processed meat, and salt.

CONCLUSION

In the French context, although issues with the intake of certain nutrients may occur, a diet that remains within the planetary limits as the EAT-Lancet reference diet allows a favorable nutritional quality.

TRIAL REGISTRATION NUMBER

NCT03335644.

Shifting towards optimized healthy and sustainable Dutch diets: impact on protein quality

PURPOSE

To reduce the environmental impact of Western diets, a reduction of meat consumption and a substitution by plant-based protein sources is needed. This protein transition will affect the quantity and quality of dietary protein. Therefore, the aim of this study was to evaluate the protein adequacy of diets optimized for nutritional health and diet-related greenhouse gas emission (GHGE).

METHODS

Data from 2150 adult participants of the Dutch National Food Consumption Survey were used, with diet assessed using two non-consecutive 24 h dietary recalls. Utilizable protein of current diets per day was based on meal composition and the Protein Digestibility-Corrected Amino Acid Score and was compared to protein requirements. Optimized diets were derived as linear combinations of current diets that minimized GHGE and maximized the Dutch Healthy Diet 2015 score, with/without constraints to keep dietary change within 33% of current consumption. Protein adequacy was evaluated in both current and optimized diets.

RESULTS

In all age and gender strata, the healthiest diets had higher GHGE, the most sustainable diets had the lowest dietary quality, though higher than current diets, and protein adequacy remained sufficient. When limiting dietary change to 33% of current consumption, in the most promising trade-off diet GHGE was reduced by 12-16%. The current diet provided 1.4-2.2 times the required amount of utilizable protein.

CONCLUSION

These results suggest that a realistic aim for the next decade might be to reduce diet-related GHGE to 12-16% of the current levels without compromising protein adequacy and diet quality. To achieve global targets, upstream food system transformations are needed with subsequent dietary changes.

Dietary protein consumption profiles show contrasting impacts on environmental and health indicators

Patterns of protein intake are strong characteristics of diets, and protein sources have been linked to the environmental and nutrition/health impacts of diets. However, few studies have worked on protein profiles, and most of them have focused on specific diets like vegetarian or vegan diets. Furthermore, the description of the environmental impact of diets has often been limited to greenhouse gas emissions (GHGe) and land use. This paper analyzes the alignment of environmental pressures and nutritional impacts in a diversity of representative protein profiles of a western population. Using data from a representative survey in France (INCA3, n = 1125), we identified protein profiles using hierarchical ascendant classification on protein intake (g) from main protein sources (refined grains, whole grains, dairy, eggs, ruminant meat, poultry, pork, processed meat, fish, fruits & vegetables, pulses). We assessed their diet quality using 6 dietary scores, including assessment of long-term risk for health, and associated 14 environmental pressure indicators using the Agribalyse database completed by the SHARP database for GHGe. Five protein profiles were identified according to the high contributions of ruminant meat, pork, poultry, fish, or, conversely, as low contribution from meat. The profile including the lowest protein from meat had the lowest impact on almost all environmental indicators and had the lowest long-term risk. Conversely, the profile with high protein from ruminant-based foods had the highest pressures on most environmental indicators, including GHGe. We found that the protein profile with low contribution from meat has great potential for human health and environment preservation. Shifting a large part of the population toward this profile could be an easy first step toward building a more sustainable diet.

Associations of daily diet-related greenhouse gas emissions with the incidence and mortality of chronic diseases: a systematic review and meta-analysis of epidemiological studies

OBJECTIVES

Although the entire process extending from food production to dietary consumption makes a large contribution to total greenhouse gas (GHG) emissions, little and inconsistent evidence exists on the epidemiological associations of daily diet-related GHG emissions with chronic disease risk or all-cause mortality. This systematic review and meta-analysis explored the observational epidemiological relationship between daily diet-related GHG emissions and health outcomes, including the risk of chronic diseases and all-cause mortality.

METHODS

Original articles published in English until May 2022 were identified by searching PubMed, Ovid-Embase, Web of Science, CINAHL, and Google Scholar. The extracted data were pooled using both fixed-effects and random-effects meta-analyses and presented as hazard and risk ratios (RRs) with 95% confidence intervals (CIs).

RESULTS

In total, 7 cohort studies (21 study arms) were included for qualitative synthesis and meta-analysis. The GHG emissions of dietary consumption showed a significant positive association with the risk of chronic disease incidence and mortality in both fixed-effects and random-effects models (fixed: RR, 1.04; 95% CI, 1.03 to 1.05; random: RR, 1.04; 95% CI, 1.02 to 1.06). This positive association was robust regardless of how daily diet-related GHG emissions were grouped. More strongly animal- based diets showed higher GHG emissions. However, there were only a few studies on specific chronic diseases, and the subgroup analysis showed insignificant results. There was no evidence of publication bias among the studies (Egger test: p=0.79).

CONCLUSIONS

A higher GHG-emission diet was found to be associated with a greater risk of all-cause mortality.

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.

Nutritionally adequate and environmentally respectful diets are possible for different diet groups: an optimized study from the NutriNet-Santé cohort

BACKGROUND

Research has shown that vegetarian diets have a low environmental impact, but few studies have examined the environmental impacts and nutritional adequacy of these diets together, even though vegetarian diets can lead to nutritional issues.

OBJECTIVES

Our objective was to optimize and compare 6 types of diets with varying degrees of plant foods (lacto-, ovolacto-, and pescovegetarian diets and diets with low, medium, and high meat content) under nutritional constraints.

METHODS

Consumption data in 30,000 participants were derived from the French NutriNet-Santé cohort using an FFQ. Diets were optimized by a nonlinear algorithm minimizing the diet deviation while meeting multiple constraints at both the individual and population levels: nonincrease of the cost and environmental impacts (as partial ReCiPe accounting for greenhouse gas emissions, cumulative energy demand, and land occupation, distinguishing production methods: organic and conventional), under epidemiologic, nutritional (based on nutrient reference values), and acceptability (according to the diet type) constraints.

RESULTS

Optimized diets were successfully identified for each diet type, except that it was impossible to meet the EPA (20:5n-3) + DHA (22:6n-3) requirements in lacto- and ovolactovegetarians. In all cases, meat consumption was redistributed or reduced and the consumption of legumes (including soy-based products), whole grains, and vegetables were increased, whereas some food groups, such as potatoes, fruit juices, and alcoholic beverages, were entirely removed from the diets. The lower environmental impacts (as well as individual indicators) observed for vegetarians could be attained even when nutritional references were reached except for long-chain n-3 (omega-3) fatty acids.

CONCLUSIONS

A low-meat diet could be considered as a target for the general population in the context of sustainable transitions, although all diets tested can be overall nutritionally adequate (except for n-3 fatty acids) when planned appropriately.This trial was registered at clinicaltrials.gov as NCT03335644.

Incorporating environmental and sustainability considerations into health technology assessment and clinical and public health guidelines: a scoping review

Healthcare systems account for a substantial proportion of global carbon emissions and contribute to wider environmental degradation. This scoping review aimed to summarize the evidence currently available on incorporation of environmental and sustainability considerations into health technology assessments (HTAs) and guidelines to support the National In stitute for Health and Care Excellence and analogous bodies in other jurisdictions developing theirown methods and processes. Overall, 7,653 articles were identified, of which 24 were included in this review and split into three key areas - HTA (10 studies), healthcare guidelines (4 studies), and food and dietary guidelines (10 studies). Methodological reviews discussed the pros and cons of different approaches to integrate environmental considerations into HTAs, including adjustments to conventional cost-utility analysis (CUA), cost-benefit analysis, and multicriteria decision analysis. The case studies illustrated the challenges of putting this into practice, such as lack of disaggregated data to evaluate the impact of single technologies and difficulty in conducting thorough life cycle assessments that consider the full environmental effects. Evidence was scant on the incorporation of environmental impacts in clinical practice and public health guidelines. Food and dietary guidelines used adapted CUA based on life cycle assessments, simulation modeling, and qualitative judgments made by expert panels. There is uncertainty on how HTA and guideline committees will handle trade-offs between health and environment, especially when balancing environmental harms that fall largely on society with health benefits for individuals. Further research is warranted to enable integration of environmental considerations into HTA and clinical and public health guidelines.

Nutritional issues and dietary levers during gradual meat reduction - A sequential diet optimization study to achieve progressively healthier diets

BACKGROUND & AIMS

Reducing meat consumption is a current trend and a strong prospect for the future in Western countries, but its dietary modalities and nutrient challenges remain poorly documented. Using diet optimization under a broad set of constraints, we tried to identify a sequential meat reduction transition and analyze its nutrient issues and dietary levers.

METHODS

Based on the consumption of French adults (INCA3, n = 1 125, 18-64 years old), we modeled a transition towards a nutritionally adequate healthy dietary pattern under the constraint of a gradual reduction in meat consumption in successive 10% steps. Using a multi-criteria optimization procedure, the diet modeled at each meat reduction step was to be healthier but close to the previous diet.

RESULTS

The most significant changes occurred early in the modeled transition process, with drastic reductions in processed and red meats in favor of poultry, which rapidly became the predominant meat before gradually decreasing from 50% to 100% meat reduction. At the same time, whole grain products, fruits and vegetables consumption increased rapidly to reach a plateau from 50% meat reduction onwards. Some nutrients were limiting, in particular bioavailable iron and zinc, and vitamin A, but sufficient intakes were achieved by restructuring diets based on food groups other than meat. Other nutrients mainly supplied by meat such as vitamin B6 and B12, protein and indispensable amino acids, were never limiting.

CONCLUSION

Healthy and nutritionally adequate food patterns can be identified throughout a transition to complete meat reduction. After a 50% reduction in meat consumption, poultry is almost the only meat remaining and its further reduction makes the diet only marginally healthier.

Association between adherence to the EAT-Lancet diet and risk of cancer and cardiovascular outcomes in the prospective NutriNet-Santé cohort

BACKGROUND

The EAT-Lancet commission proposed, in 2019, a planetary, healthy, and universal dietary pattern. However, this diet has rarely been studied in relation to various health outcomes.

OBJECTIVES

We aimed to prospectively estimate the association between the EAT-Lancet diet and cancer and cardiovascular disease (CVD) risk.

METHODS

The study was conducted in participants of the NutriNet-Santé cohort (2009-2021). The endpoints were the incident outcomes (cancer and CVDs and mortality from these diseases), combined and separately. Adherence to the EAT-Lancet diet was estimated using the EAT-Lancet Diet Index (ELD-I) modeled as quintiles (Qs). Multivariable Cox proportional hazard models were used to estimate HRs and 95% CIs, adjusted for potential confounders and moderators.

RESULTS

A total of 62,382 subjects were included; 2475 cases of cancer and 786 cases of cardiovascular events occurred during a median follow-up of 8.1 y. The sample was 76% female, the mean ± SD age at inclusion was 51.0 ± 10.2 y. The ELD-I ranged from -162 to 332 points with a mean ± SD score of 45.4 ± 25.6 points. In multivariable models, no significant association between the EAT-Lancet diet and the risk of cancer and CVD combined, and separately, was observed. Alcohol consumption was an effect modifier of the association. A significant association was observed among low drinkers (HRQ5vs.Q1: 0.86; 95% CI: 0.73, 1.02; P-trend = 0.02). A higher ELD-I was significantly associated with a lower risk of overall cancer only among females (HRQ5vs.Q1: 0.89; 95% CI: 0.75, 1.05; P-trend = 0.03). Both associations were largely attenuated by BMI.

CONCLUSIONS

Contrary to our hypothesis, our results documented significant associations between adherence to the EAT-Lancet diet and incidence of cancer only in some subgroups, and no association with CVD.This trial was registered at clinicaltrials.gov as NCT03335644.

Climate change and the urgency to transform food systems

Without rapid changes to agriculture and food systems, the goals of the 2015 Paris Agreement on climate change will not be met. Food systems are one of the most important contributors to greenhouse gas (GHG) emissions, but they also need to be adapted to cope with climate change impacts. Although many options exist to reduce GHG emissions in the food system, efforts to develop implementable transformation pathways are hampered by a combination of structural challenges such as fragmented decision-making, vested interests, and power imbalances in the climate policy and food communities, all of which are compounded by a lack of joint vision. New processes and governance arrangements are urgently needed for dealing with potential trade-offs among mitigation options and their food security implications.

Principles for Evidence-Based and Sustainable Food System Innovations for Healthier Diets

Climate change, rapid urbanization, war, and economic recession are key drivers of the current food systems’ disruption, which has been exacerbated by the COVID pandemic. Local, regional, and global food systems are unable to provide consumers with nutritious and affordable diets. Suboptimal diets exacerbate the triple burden of malnutrition, with micronutrient deficiencies affecting more than two billion people, two billion people suffering from overweight, and more than 140 million children who are stunted. The unaffordability of nutritious diets represents an obstacle for many, especially in low- and middle-income countries where healthy diets are five times more expensive than starchy staple diets. Food system transformations are urgently required to provide consumers with more affordable and nutritious diets that are capable of meeting social and environmental challenges. In this review, we underline the critical role of innovation within the food system transformation discourse. We aim to define principles for implementing evidence-based and long-term food system innovations that are economically, socially, and environmentally sustainable and, above all, aimed at improving diets and public health. We begin by defining and describing the role of innovation in the transformation of food systems and uncover the major barriers to implementing these innovations. Lastly, we explore case studies that demonstrate successful innovations for healthier diets.

Plant-Based Dietary Patterns for Human and Planetary Health

The coronavirus pandemic has acted as a reset on global economies, providing us with the opportunity to build back greener and ensure global warming does not surpass 1.5 °C. It is time for developed nations to commit to red meat reduction targets and shift to plant-based dietary patterns. Transitioning to plant-based diets (PBDs) has the potential to reduce diet-related land use by 76%, diet-related greenhouse gas emissions by 49%, eutrophication by 49%, and green and blue water use by 21% and 14%, respectively, whilst garnering substantial health co-benefits. An extensive body of data from prospective cohort studies and controlled trials supports the implementation of PBDs for obesity and chronic disease prevention. The consumption of diets high in fruits, vegetables, legumes, whole grains, nuts, fish, and unsaturated vegetable oils, and low in animal products, refined grains, and added sugars are associated with a lower risk of all-cause mortality. Meat appreciation, health concerns, convenience, and expense are prominent barriers to PBDs. Strategic policy action is required to overcome these barriers and promote the implementation of healthy and sustainable PBDs.

Diets with Higher Vegetable Intake and Lower Environmental Impact: Evidence from a Large Australian Population Health Survey

Increasing the consumption of vegetables is a public health nutrition priority in Australia. This must be achieved in the context of lowering dietary environmental impacts. In this study, a subgroup of 1700 Australian adult daily diets having a higher diet-quality score and a lower environmental impact score was isolated from Australian Health Survey data. These diets were primarily distinguished by their lower content of energy-dense/nutrient-poor discretionary foods. Among these diets, those with higher levels of vegetable intake were characterized by greater variety of vegetables eaten, lower intake of bread and cereal foods, and higher intake of red meat. These diets also had a greater likelihood of achieving recommended intakes for a range of vitamins and minerals. These findings highlighted the importance of considering the total diet in developing strategies to promote healthy and sustainable food consumption, as well as the need to understand the interrelationships between foods that exist in a local cultural context. As vegetables are usually eaten with other foods, higher vegetable consumption in Australia could be supported by encouraging more regular consumption of the types of meals that include larger quantities of vegetables. Our results showed that this was possible while also substantially lowering total dietary environmental impacts.

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

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

Are recent dietary changes observed in the NutriNet-Santé participants healthier and more sustainable?

PURPOSE

While intensive modern food systems have significant unfavourable impacts on health and the environment, new sustainable food consumption trends have been emerging in recent years. This study identified recent dietary trends over a 4-year period in terms of overall dietary patterns and organic foods consumption and associated socio-demographic determinants.

METHODS

Food intakes were assessed among 18,108 participants of the NutriNet-Santé cohort in 2014 and 2018. A food frequency questionnaire was used to estimate organic and conventional food consumption. Change in food consumption, quality of the diet (assessed by the adherence to the French national guidelines), plant-based diet using published scores, organic food intake were evaluated in regard with various socio-demographic factors. The paired student t test to compare dietary intake and the Kruskal-Walllis test to consider socio-demographic characteristics were used.

RESULTS

Consumption of meat and processed meat decreased respectively by 5.09 g/day (SD 51.15) and 1.12 g/day (SD 26.05). The average total consumption of organic products increased by 12% (+ 93 g/day) while consumption of organic fish and seafood (- 1.4 g/day), poultry (- 1 g/day), processed meat (- 0.3 g/day) and meat (- 3.3 g/day) decreased. The dietary towards healthier diets was more pronounced in certain population subgroups. For example, females, young individuals and postgraduate participants were more likely to increase their consumption of healthful plant and animal-based foods, organic foods and to improve the overall nutritional quality of their diets during the follow-up period than their counterparts.

CONCLUSION

Our results indicate a slight inflexion towards healthier and plant-based diets over a 4-year period at least in some segments of the population. A decrease in the consumption of animal products and an increase in the consumption of healthful plant-based foods and organic foods suggests a potential trend towards more sustainable diets among certain subgroups. The environmental impacts of these changes need to be assessed in further works as well as the way to sustain and improve them, in particular those who do not initiate sustainable transition.

Low Meat Consumption in the Netherlands Is Associated With Higher Intake of Fish, Nuts, Seeds, Cheese, Sweets, and Snacks: Results From a Two-Part Model

Studies on sustainable diets show a need for replacement of animal-based foods by plant-based foods, which is also called "the protein transition." To gain insight into the acceptability of such diet shifts, this study evaluated which current food sources people consume at varying amounts of meat consumption. The study population consisted of 4,313 participants aged 1-79 years of the Dutch National Food Consumption Survey 2012-2016, which assessed diet using two nonconsecutive 24-h dietary recalls. A two-part statistical model was used that accounts for both repeated measures and the correlation between probability and amount of consumption. Results are presented for quartiles of low to high meat consumption, by age and sex. Depending on age and sex, a higher consumption of fish (>100%), nuts and seeds (73-156%), cheese (34-111%), and sweets and snacks (28-81%) is observed in the lowest quartile of meat consumption compared to the highest. For fish, nuts, seeds, and cheese, this increase is mainly due to probability of consumption (>100%, 61-93%, and 16-64%, respectively). For sweets and snacks, the increase is mainly due to the amount of consumption (26-72%). Probability of potato consumption is 29-51% lower at low meat consumption. Vegetable consumption is lower mainly due to amount of consumption (6-29%). The results from the two-part model suggest that shifting away from a traditional Dutch high meat-vegetable-potatoes pattern is associated with higher probability of consuming fish, nuts and seeds, and cheese, but also increased amounts of sweets and snacks. This illustrates that analyzing the probability and amount part separately in relation to behavioral or physiological determinants extends our understanding of the diet according to meat consumption. These insights are important when developing realistic and acceptable food-based dietary guidelines for meat reduction.

Using Linear Programming to Determine the Role of Plant- and Animal-Sourced Foods in Least-Cost, Nutritionally Adequate Diets for Adults

BACKGROUND

The respective roles of plant- and animal-sourced foods in sustainable healthy diets for humans remain unclear. Nutritional quality and the monetary cost of diets are key criteria among others for sustainable food production.

OBJECTIVE

Linear programming (LP) was used to determine the composition of nutritionally adequate dietary patterns formulated at the lowest cost. The hypothesis tested was that animal-sourced foods would be included in least-cost diets due to their high density of particular essential nutrients.

METHODS

The LP modeling work was based on eating patterns, retail food prices (2020), and the daily energy (11,150 kJ, 2665 kcal) and essential nutrient requirements (29 nutrients in total) of a reference adult in New Zealand (NZ). The LP modeling approach is publicly and freely available to readily illustrate the change in dietary profiles and daily diet cost, in the simulation of changes in energy and nutrient requirements, and price fluctuations within food groups.

RESULTS

A nutrient-adequate, least-cost dietary pattern formulated from 883 foods, with a daily cost of NZ $3.23, included both animal- and plant-based foods. The nutrients found to be equally first-limiting were biotin, calcium, molybdenum, potassium, selenium, vitamin A, pantothenic acid, and vitamin C. When a dietary scenario with no animal-sourced foods was modeled, by increasing the retail prices of animal-sourced foods by 1.05 to 10.3 times, the daily cost of this plant-only dietary pattern was NZ $4.34. Additional nutrients, such as zinc, vitamin B-12, and vitamin D, were met at their daily minimum required levels.

CONCLUSIONS

Dietary patterns formulated at the lowest cost and meeting the daily minimum requirements for energy and essential nutrients for an adult in New Zealand relied on foods sourced from animals and plants.

Food Systems Transformation for Child Health and Well-Being: The Essential Role of Dairy

Malnutrition, in all its forms, during the critical stages of child growth and development can have lifelong impacts on health and well-being. While most forms of malnutrition can be prevented with simple dietary interventions, both undernutrition and overnutrition remain persistent and burdensome challenges for large portions of the global population, especially for young children who are dependent on others for nourishment. In addition to dietary factors, children's health also faces the growing challenges of climate change, environmental degradation, pollution, and infectious disease. Food production and consumption practices both sit at the nexus of these issues, and both must be significantly transformed if we are to achieve the 2030 Sustainable Development Goals. Food sources (i.e., animal-source foods vs. plant-source foods), food production practices, the effects of food processing, the impacts of a more globalized food system, and food loss and waste have all been receiving growing attention in health and sustainability research and policy discussions. Much of this work points to recommendations to reduce resource-intensive animal-source foods, heavily processed foods, and foods associated with excessive waste and pollution, while simultaneously increasing plant-source options. However, some of these recommendations require a little more nuance when considered in the context of issues such as global child health. All types of foods can play significant roles in providing essential nutrition for children across the globe, and for improving the well-being and livelihoods of their families and communities. Dairy foods provide a prime example of this need for nuance, as both dairy production practices and consumption patterns vary greatly throughout the world, as do their impacts on child health and food system sustainability. The objective of this narrative review is to highlight the role of dairy in supporting child health in the context of food system sustainability. When considering child health within this context it is recommended to take a holistic approach that considers all four domains of sustainability (health, economics, society, and the environment) to better weigh trade-offs, optimize outcomes, and avoid unintended consequences. To ensure that children have access to nutritious and safe foods within sustainable food systems, special consideration of their needs must be included within the broader food systems transformation narrative.

Halving food-related greenhouse gas emissions can be achieved by redistributing meat consumption: Progressive optimization results of the NutriNet-Santé cohort

BACKGROUND

Diet-related greenhouse gas emissions (GHGe) mainly comes from animal-sourced foods. As progressive changes are more acceptable for a sustainable food transition, we aimed to identify nutritionally adequate and culturally acceptable optimized diets ensuring a gradual reduction in GHGe, using observed diet from a large sample of French adults, while considering the mode of food production (organic vs conventional farming) and the co-production link between milk and beef.

MATERIAL AND METHOD

Based on the consumption of 257 organic and conventional foods among 29,413 participants (75% women, age: 53.5 ± 14.0y) of the NutriNet-Santé study, we modelled optimal diets according to GHGe reduction scenarios in 5% steps, from 0 to 50% with nutritional, acceptability, and coproduct constraints, for men, premenopausal and menopausal women separately.

RESULTS

Gradual GHGe decrease under these constraints led to optimal diets with an overall decrease in animal foods, with marked reductions in dairy products (up to -83%), together with a stable but largely redistributed meat consumption in favor of poultry (up to +182%) and pork (up to +46%) and at the expense of ruminant meat (down to -92%). Amounts of legumes increases dramatically (up to +238%). The greater the reduction in diet-related GHGe, the lower the cumulative energy demand (about -25%) and land use (about -43%). The proportion of organic food increased from ~30% in the observed diets to ~70% in the optimized diets.

CONCLUSION

Our results suggest that meeting both nutrient reference value and environmental objectives of up to 50% GHGe reduction requires the reduction of animal foods together with important substitutions between animal food groups, which result in drastic reductions in beef and dairy products. Further research is required to explore alignment with long-term health value and conflict with acceptability, in particular for even greater GHGe reductions.

The Complementary Roles for Plant-Source and Animal-Source Foods in Sustainable Healthy Diets

There are approximately 100 countries with food-based dietary guidelines throughout the world, each of which aims to encompass the cultural, geographical, and health considerations unique to their country of origin. Common themes throughout these guides emphasize diverse and balanced intake of food groups from both plant- and animal-sources. With the globally recognized need to shift to more sustainable food systems, several countries and international food and health organizations have begun to incorporate sustainability recommendations into their dietary guidance. These sustainability recommendations are often based on food source (i.e., eat more plant-source and fewer animal-source foods), yet food source may not be the only useful or informative comparator for assessing healthy and sustainable diets. The purpose of this narrative review is to examine the roles of plant-source foods and animal-source foods in the context of sustainable healthy diets-with an emphasis on the contributions of the most commonly recommended food groups from global food-based dietary guidelines (i.e., fruits, vegetables, and dairy foods). Overall, plant and animal agriculture have complementary and symbiotic roles in healthy and sustainable food systems, and these abilities are largely dependent on various contextual factors (e.g., geography, production practices, processing methods, consumption patterns)-not just on whether the food originated from the plant or animal kingdom.

Perspective: Modeling Healthy Eating Patterns for Food-Based Dietary Guidelines-Scientific Concepts, Methodological Processes, Limitations, and Lessons

The relations between dietary features and human health are varied and complex. Health-related variables are many and they have intricate relations at different and interrelated nutritional levels: nutrients, food groups, and the complex overall pattern. Food-based dietary guidelines (FBDGs) are principally designed to synthesize this information to make it available to the public. Here, we describe the method used to establish healthy eating patterns (HEPs) for the latest French FBDGs, which consists of in-depth food pattern modeling using an enhanced optimization method that gathered all aspects of HEPs. We present the novelty of this food modeling approach for FBDGs, which aims to gather information related to nutrients, food contaminants, and epidemiological relations with long-term health, and to be combined with the objective of realistic dietary patterns that deviate minimally from the prevailing diet. We draw lessons from stepwise implementation of the method and discuss its strengths, limitations, and perspectives. In light of the modeled HEPs, we discuss the importance of food grouping; of accounting for dietary habits while not precluding modeled diets that can be realistic/acceptable; and of taking into account the exposure to food contaminants. We discuss the tolerance and flexibility to be applied to certain dietary reference values for nutrients and health-based guidance values for contaminants so that HEPs can ultimately be identified, and how account can be taken of varied health-related outcomes applied to food groups. Although the approach involves all the peculiar uncertainties of numerous optimization model parameters and input data, its merit is that it offers a rationalized approach to establishing HEPs with multiple constraints and competing objectives. It is also versatile because it is possible to operationalize further dimensions of dietary patterns to favor human and planetary health.

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.

Conservative to disruptive diets for optimizing nutrition, environmental impacts and cost in French adults from the NutriNet-Santé cohort

Improving the sustainability of diets requires the identification of diets that meet the nutritional requirements of populations, promote health, are within planetary boundaries, are affordable and are acceptable. Here we explore the extent to which dimensions of sustainability could be optimally aligned and identify more sustainable dietary solutions, from the most conservative to the most disruptive, among 12,166 participants of the NutriNet-Santé cohort. We aim to concomitantly lower environmental impacts (including greenhouse gas emissions, cumulative energy demand and land occupation), increase organic food consumption and study departure from observed diets (considered as a proxy for acceptability). From the most conservative to the most disruptive scenario, optimized diets were gradually richer in fruits, vegetables and soya-based products and markedly poorer in animal-based foods and fatty and sweet foods. The contribution of animal protein to total protein intake gradually decreased by 12% to 70% of the observed value. The greenhouse gas emissions from food production for the diets gradually decreased across scenarios (as a percentage of observed values) by 36-86%, land occupation for food production by 32-78% and energy demand by 28-72%. Our results offer a benchmark of scenarios of graded dietary changes against graded sustainability improvements.

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.

Development of a Danish Adapted Healthy Plant-Based Diet Based on the EAT-Lancet Reference Diet

Plant-based diets have been linked to both health benefits and a lower climate impact. However, plant-based diets may represent both healthy and unhealthy dietary practices. The present study aimed to develop a nationally adapted healthy plant-based diet based on the global EAT-Lancet reference diet. Development took place in a series of steps. First, the original EAT-Lancet reference diet was evaluated based on food availability, i.e., using Danish food data (Model 1). Then, the model was further modified to reflect national food based dietary guidelines (FBDG) and characteristics of current consumption pattern, e.g., by including processed food, discretionary foods and beverages in the diet (Model 2). The contents of macronutrients, vitamins and minerals, except for vitamin D and iodine, were found to be sufficient for Model 2, according to the recommended nutrient density to be used for planning diets for groups of individuals aged 6–65 years. In addition, the study gave an insight into the nutrients and foods to be aware of in planning a predominantly plant-based diet, thereby providing directions for future revisions of sustainable FBDGs. These include a stronger emphasis on the intake of legumes, nuts and seeds, fruit and vegetables including dark green vegetables, whole-grain products and vegetable oils as well as lowering meat intake.