Consuming a vegan diet can cut carbon emissions by 46 per cent, land use impacts by 33 per cent, and water footprints by seven per cent, a new study has found.
According to the Spanish-led study published today in the Frontiers in Nutrition journal, plant-based diets are “equally nutritious and healthy” as a Mediterranean diet and “much better for the planet.”
To reach their findings, researchers form the University of Granada and the Spanish National research Council designed four weekly menus with an equal energy value that followed international recommendations for the daily intake of a wide range of macro and micro-nutrients.
Each menu was developed using the same amount of calories in accordance with an omnivorous Mediterranean diet based on meat, fish, and vegetables, a pesco-vegetarian diet featuring fish and vegetables, an ovo-lacto-vegetarian diet that excludes meat and fish but includes dairy, and a fully vegan diet that excludes all animal-based products.
The vegan diet was found to cut carbon emissions by around half compared to the Mediterranean, while the vegetarian and pesco-vegetarian diets were found to cut carbon emissions by up to 35 per cent.
In terms of nutrition, the three plant-based diets were found to be nutritionally balanced, except for small deficiencies in vitamin D, iodine, and vitamin B12, which researchers said could be easily remedied with supplements.
In addition to generating less CO2 and using less land and water, researchers found the vegan diet also lowered other pollutants linked to global warming.
To estimate the total ecological footprint of each menu, researchers analysed a range of key ecosystem impact indicators, ranging from climate change and ozone depletion to water eutrophication and ecotoxicity, which results in excess pollutants in water.
The results showed that ‘cradle-to-home’ 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, 2.6kg per day for the ovo-lacto-vegetarian diet, to just 2.1kg per day for the vegan diet – a reduction of 46 per cent.
Researchers said a similar pattern was found for water use, which dropped by seven per cent from 10.2 cubic meters of water for the omnivorous diet to 9.5 cubic meters for the vegan diet.
The same was reported for agricultural land occupation, which fell by 33 per cent from 226 to 151 points on a weighted environmental impact score associated with land use, expressed per day of diet.
Researchers said the vegan diet also showed reductions of more than 50 per cent in key ecosystem impact indicators when compared with the omnivorous baseline, along with a greater than 55 per cent decrease in disease incidence.
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, said “the pattern was clear: the more plant-foods, the smaller the ecological footprint”.
She added that for those that want to change their eating habits to reduce environmental impacts but are not prepared to give up animal-based foods entirely, it is not necessary “to go fully vegan to make a difference”.
“Even small steps toward a more plant-based diet reduce emissions and save resources,” she said. “Every meal that includes more plants helps move us toward healthier people and a healthier planet.”
Dining and Cooking