Research reveals that switching to a vegan diet can reduce greenhouse gas emissions by 46% and land use by 33% while still meeting almost all essential nutrient needs
A recent study found that adopting a vegan diet can reduce carbon emissions by nearly half and decrease land use by a third compared to a Mediterranean omnivorous diet, while still providing almost all essential nutrients. The research analysed calorie-matched diet menus and assessed environmental footprints across multiple food systems, showing dramatic benefits when moving toward more plant-based options.
The findings are detailed in Frontiers in Nutrition.
Vegan diet: Reducing premature mortality and environmental impact
Approximately 1.1% of the world’s population is vegan, with many citing health benefits as the primary reason for their dietary change. Figures suggest that moving from a typical Western diet to a vegan diet can lower the risk of premature mortality from noncommunicable diseases by an estimated 18%-21%.
This new study has meticulously calculated the environmental impact of a vegan diet, providing precise figures on how plant-based diets, such as veganism, can significantly lower emissions and the use of natural resources.
“We compared diets with the same amount of calories and found that moving from a Mediterranean to a vegan diet generated 46% less CO2 while using 33% less land and 7% less water, and also lowered other pollutants linked to global warming,” said Dr Noelia Rodriguez-Martín, a postdoctoral researcher at the Instituto de la Grasa of the Spanish National Research Council now based at the University of Granada, and the corresponding author of the new study.
Rodriguez-Martín and the research team took a practical approach. They designed four sets of nutritionally balanced daily menus, each lasting a week. Each diet delivered 2,000 calories, based on recommendations of the Spanish Society for Community Nutrition, the Spanish Vegetarian Union, the European Food Safety Authority, and the US National Academy of Medicine.
Comparing veganism to an omnivorous diet
The baseline was a healthy, omnivorous Mediterranean diet rich in fruits, vegetables, whole grains, and lean protein, with moderate amounts of fish, poultry, and meat. Two others were pescatarian and ovo-lacto-vegetarian, respectively, meaning they included fish and seafood or eggs and dairy, but not meat. The fourth was vegan, where all animal-based foods had been replaced with plant-based alternatives, such as tofu, textured soy protein, tempeh, soy yoghurt, seeds, or legumes.
The researchers utilised public databases, including Spanish BEDCA and FoodData Central from the US Department of Agriculture, to calculate the macronutrient, micronutrient, and vitamin content of each menu item. They then compared these with the daily intakes recommended by health organisations for women and men between 30-51 years old and 51-70 years old.
The researchers estimated the total ecological footprint of each menu, comprising a range of key ecosystem impact indicators, including climate change, ozone depletion, water eutrophication, and ecotoxicity, based on the public database AGRIBALYSE 3.1.1.
The results showed that total greenhouse gas emissions dropped from 3.8kg per day of CO2 equivalents for the omnivorous diet, to 3.2kg per day for the pesco-vegetarian diet, and 2.6kg per day for the ovo-lacto-vegetarian diet, to 2.1kg per day for the vegan diet – a reduction by 46%.
The researchers found that switching from an omnivorous diet to a vegan diet reduced water usage by 7%, from 10.2 to 9.5 cubic meters, and decreased agricultural land use by 33%, from 226 to 151 points. The vegan diet also resulted in over a 50% reduction in key ecosystem impact indicators and a more than 55% decrease in disease incidence.
Dr. Rodriguez-Martín reassures, “Our analyses showed that all three plant-based menus were nutritionally balanced, with only vitamin D, iodine and vitamin B12 needing a bit more attention. Overall, the indicators clearly highlight the environmental and health advantages of plant-based diets compared with the omnivorous baseline.”
