Background: Food systems, particularly livestock production, account for substantial greenhouse gas (GHG) emissions, while unhealthy diets, characterized by excessive animal-based and insufficient plant-based food consumption, are a major risk factor for all-cause mortality in Europe. Implementing climate mitigation policies related to the GHG emissions of the food system could therefore bring important health co-benefits. Methods: We developed a health impact assessment model based on a life table approach and evaluated the mortality impact of transitions in food consumption through four contrasting scenarios leading to net-zero GHG emissions for France in 2050. These involved varying dietary shifts, all moving toward more plant-based foods. For each scenario, we modeled the evolution of the diet, as well as the impacts on all-cause mortality by applying the most recent and robust dose-response relationships derived from meta-analyses for 13 food groups. Findings: The different trajectories of dietary shifts translated into a health impact ranging from 19% [uncertainty interval, UI: 17%-21%] to 24% [UI: 21%-26%] of all-cause mortality prevented in 2050 in the French population. Variation in intakes of nuts, red meat, processed meat, whole grains and legumes bring most of the health benefits. Whatever the parameters chosen in the sensitivity analyses, the results remained robust, with about 100,000 to 200,000 deaths that could be prevented yearly by 2050 in France. Interpretation: The present study highlights the considerable potential health benefits that trajectories toward net-zero emissions can bring, especially through shifts toward sustainable diets. These results reinforce the strong convergence of environmental and human health issues in the agri-food sector. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Protocols ### Funding Statement This study was funded by the French High Council for the Future of Health Insurance (HCAAM) and the National Agency for Ecological Transition (Ademe). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors
Background Food systems contribute to environmental degradation and diet-related diseases. While numerous dietary recommendations exist, systematic quantification of trade-offs between health and environmental objectives remains limited, particularly in France, where no such optimization study has been conducted. Methods We applied multi-criteria optimization to map the Pareto front between health risk (based on Global Burden of Disease targets) and environmental pressures (greenhouse gas emissions, water use, land occupation, pesticide use, ecological infrastructure, and energy demand). We identified optimal diets under varying acceptability constraints that limit deviations from current dietary patterns. Baseline data were from 29,413 NutriNet-Santé cohort participants (France, 2014). Findings The Pareto front reveals both substantial co-benefits and conflicts between health and environmental objectives. One optimal solution with relaxed acceptability constraints features 700g fruits/vegetables daily, 60g pulses, 290g whole grains, 350 mL milk and 70g other dairy daily, up to 35g poultry weekly and 250g fish weekly. Compared to baseline, this diet improves health score by 145% while reducing overall environmental pressures by 18%, with decreases of 73% (GHG emissions), 59% (land occupation), 55% (energy demand), 79% (pesticide use), and 6% (water use). The proportion of organic food increases by 161% and costs remain stable (±3%). However, ecological infrastructure decreased by 47%, revealing trade-offs between biodiversity preservation and other environmental goals. Conclusions This first comprehensive analysis for France systematically quantifies health-environment trade-offs, revealing where objectives align and conflict, thereby providing evidence to inform public policies balancing human and planetary health. Despite substantial dietary changes, these diets remain feasible and affordable. Trial registration The NutriNet-Sante cohort is registered at clinicaltrials.gov (NCT03335644).
Reinforcing the regulation of pests by their natural enemies is a promising way of reducing the use of pesticides and can be achieved through the adoption of management options at multiple scales, from field to landscape. In practice, however, most management efforts concentrate on modifying farming practices at the field level and examples of implementation of landscape-scale pest management strategies are scarce. Here, we report on place-based research that combined the co-design of scenarios of landscape-scale changes in farming practices and ex ante evaluation of pest control services under such scenarios, through the development of predictive models mobilizing long-term local data in two contrasting landscape case studies. We found that scenarios of farming change and predictive models of pest control services were site-specific. In both case studies, we show a high degree of spatial interdependency between farmers in the delivery of on-farm pest control services and, more importantly, that a wide adoption of pest control friendly-farming practices in the landscape leads to a win-win situation for each individual farmer. Farms that implemented changes were predicted to increase on-farm pest control services between 2
Increasing awareness of the health, environmental, and geopolitical issues associated to mineral fertilizers have brought renewed attention to alternative sources of nutrients, such as those that flow from the sanitation systems of cities. This raises the questions: how much can we recover from source-separated human urine and feces? Where are the largest deposits? Where should we start? To answer these as precisely as possible—taking into account the specificity of the area of interest, such as local diets or population pyramid—this work proposes a detailed model of the local territorial metabolism and the associated flows of nitrogen and phosphorus. As it can be adapted for any country to assess deposits at various scales, from national down to the individual building, it can support both policymakers and local urban planners. The model consists in the combination of equations describing human metabolism, information on the local diet, and open statistics on the populations inhabiting the area. Its results are validated against sanitation data from two areas in France and the Netherlands and compared to previous works in the scientific literature. We also demonstrate how the model can be used to inform prospective analyses on the evolution of the load entering sanitation systems and the nitrogen-to-phosphorus ratios, depending on population and dietary changes. Finally, we discuss how this open-source model can assist local actors in planning projects to separate human excreta and produce local and recycled fertilizers to increase their food security and autonomy.
The ability to ensure sustainable diets depends on domestic agriculture and trade, linking the transition to sustainable food systems closely with food sovereignty. This study aimed to analyze the relationships between nutritional quality, environmental impact and self-sufficiency across food groups within the current French food supply. Using the food repertoire (n=1,997 food items) and adult consumption data (n=2,121) from a representative survey, the food supply was characterized according to its nutritional, environmental and self-sufficiency dimensions. Nutritional quality was estimated using PANFood, a nutrient-based food scoring system, inspired by the PANDiet system. Environmental impact was assessed using the Environmental Footprint (EF) score aggregating 16 impacts from the Agribalyse® database. Food self-sufficiency capacity was calculated as the ratio of domestic production to food supply using international (FAOSTAT) and national databases. These three indicators were calculated for each food group based on food item data weighted by their relative consumption, enabling multidimensional distribution analysis. Overall, self-sufficiency showed no or negligible correlation with the sustainability dimensions (i.e., nutrition and environment) and the indicators exhibited substantial heterogeneity within food groups. Fruits, vegetables, and legumes demonstrated high sustainability profiles, but moderate and variable self-sufficiency. Dairy products showed high self-sufficiency alongside varied sustainability profiles. Red and processed meat exhibited poor sustainability profiles and variable self-sufficiency capacity, although overall self-sufficiency remained moderate. In France, based on the current food supply, food self-sufficiency does not align with the nutritional and environmental sustainability dimensions. However, some food groups with favorable sustainability profiles could serve as levers to enhance self-sufficiency.
