Greenhouse gas emissions, energy demand and land use associated with omnivorous, pesco-vegetarian, vegetarian, and vegan diets accounting for farming practices

International audienceIn the present context of environmental damages, food systems constitute one of the key burdens on the environment and resources. Dietary patterns emerge as a main leverage to preserve a healthy environment.The aim is to compare the environmental impacts of different diets with different levels of animal product consumption, while accounting for the type of farming systems (organic or conventional) of the food consumed.Dietary environmental impacts of the diet of 29,210 NutriNet-Santeparticipants were estimated using databases developed within the BioNutriNet project. Four diets, differing from their animal-based food proportion, were studied: omnivorous, pesco-vegetarian, vegetarian, and vegan. Three individual environmental indicators were assessed (greenhouse gas emissions, cumulative energy demand and land occupation) and combined in one aggregated partial score (pReCiPe, partial ReCiPe). Means of these indicators adjusted for energy intake were estimated across diet groups using covariance analysis.About 95% of the study sample was omnivorous. Organic consumption was much higher among nonomnivorous than other groups. The pReCiPe were 64%, 61%, and 69% lower for diet of pesco-vegetarians, vegetarians and vegans respectively, in comparison to the omnivorous diet. Regarding the three individual environmental indicators included in the pReCiPe index, the same trend was observed but trade-offs exist in organic with cumulative energy lowered and land occupation augmented.A positive link between animal-sourced food consumption and total environmental impact was observed in this large sample of French adults. By far, omnivorous had the highest-level of greenhouse gas emissions, cumulative energy demand and land occupation while vegan diets had the lowest. Further research on environmental indicators distinguishing farming practices is needed to allow a more comprehensive evaluation of the impact. (C) 2020 Institution of Chemical Engineers