08 Aug Assessing Environmental Impacts of Different Dietary Patterns
Different dietary patterns, such as vegan, vegetarian, fish-eater, and meat-eater, can entail different environmental impacts. The global interest in reducing greenhouse gas emissions, preserving biodiversity, and sustainable land and water use has led to growing calls for dietary transitions and associated research and analysis, particularly a reduction of animal-based food. However, existing dietary scenario models often do not depict real-world dietary practices and overlook variations in the environmental burden of food production and sourcing.
A recent study published in Nature Food introduces a novel approach that directly compares environmental indicators between different diet groups, while considering uncertainties related to food sourcing, production methods, and individual diet choices. The study linked data from 55,504 individuals following various diets with food-level information on greenhouse gas emissions, land use, water use, eutrophication risk, and potential biodiversity loss, including data from over 38,000 farms in 119 countries. The findings of the study revealed substantial disparities in environmental impacts based on the type of diet followed.
Vegan diets, which exclude all animal products, exhibited the lowest environmental impact, and were less than half those from high-meat-eater diets (those consuming over 100 grams of meat daily) for all studied indicators. Diets with lower meat consumption, such as vegetarian, fish-eating, and low-meat diets had at least 30% lower impacts on greenhouse gas emissions, eutrophication, and land use than high-meat diets. Interestingly, variations in environmental indicators due to food origin and production methods did not diminish the observed differences between diet groups.
While the results indicate that substantial reductions in greenhouse gas emissions can be achieved by adopting plant-based diets, uncertainties remain about the broader outcomes of such a dietary shift. The complex dynamics of the food system, changing behavioral patterns, and potential spillover effects must be considered. Notably, as Gatto et al. (2023) highlighted, decreased demand for animal-based products may lead to malnutrition, impact food affordability, and potentially result in increased consumption of non-food items with high energy consumption and/or pollution footprints. These factors mean that any proposed reductions in greenhouse gas emissions associated with dietary changes may not be practical to implement and/or could result in a range of negative outcomes, making a comprehensive approach crucial to fully understand the true impact of dietary choices on nutrition provision and food affordability, as well as on the environment.
This SNippet was written by Ejovi Abafe, a PhD Fellow in the SNi team.
Photos by Arx0nt and golubovy on Canva.