Large-scale study finds vegan diet is 30 percent better for the planet

The scientists then compared the dietary data to a database, including information on the environmental impact of 57,000 food items.

Notably, the comprehensive food dataset considered elements such as how and where a food crop is produced; for example, carrot crops grown in a greenhouse in Spain will have a different environmental impact than those cultivated in a field in the UK. 

The environmental metrics  

The environmental effect of food and beverages was evaluated using five primary metrics: greenhouse gas emissions, land usage, water use, water pollution, and biodiversity loss. 

The authors noted that even the least sustainable vegan diet was found to be more ecologically friendly than a highly sustainable meat diet.

“Unsurprisingly, diets containing more animal-based foods had higher environmental impacts. Per unit of food consumed, meat and dairy has anywhere from three to 100 times the environmental impact of plant-based foods,” the authors mentioned. 

Vegans generated just 25 percent of the dietary impact of high meat eaters in terms of greenhouse gas emissions. 

The authors conclude that the latest findings are significant since the overall food system is estimated to account for around 30 percent of global greenhouse gas emissions – the food system uses 70 percent of the global freshwater.  

“Our study and others are continuing to solidify evidence that the food system is having a massive global environmental and health impact which could be reduced by a transition towards more plant-based diets,” they mentioned.

The findings have been reported in the journal Nature Food.

Study abstract:

Modelled dietary scenarios often fail to reflect true dietary practice and do not account for variation in the environmental burden of food due to sourcing and production methods. Here we link dietary data from a sample of 55,504 vegans, vegetarians, fish-eaters and meat-eaters with food-level data on greenhouse gas emissions, land use, water use, eutrophication risk and potential biodiversity loss from a review of 570 life-cycle assessments covering more than 38,000 farms in 119 countries. Our results include the variation in food production and sourcing that is observed in the review of life-cycle assessments. All environmental indicators showed a positive association with amounts of animal-based food consumed. Dietary impacts of vegans were 25.1% (95% uncertainty interval, 15.1–37.0%) of high meat-eaters (≥100 g total meat consumed per day) for greenhouse gas emissions, 25.1% (7.1–44.5%) for land use, 46.4% (21.0–81.0%) for water use, 27.0% (19.4–40.4%) for eutrophication and 34.3% (12.0–65.3%) for biodiversity. At least 30% differences were found between low and high meat-eaters for most indicators. Despite substantial variation due to where and how food is produced, the relationship between environmental impact and animal-based food consumption is clear and should prompt the reduction of the latter.