The evidence is piling up that that global food production has a huge impact on the environment, and meat and dairy products are central to that impact. There are various ways of measuring food-related environmental impact. Life-Cycle Assessment (LCA) is an approach that looks at the “indicators from the supply chain (raw material extraction, processing, use, disposal, and related transport) required to deliver a product or service.” Put simply, it measures the environmental impact of a product from start to finish.

Perhaps unsurprisingly, these studies have shown “unequivocally” that vegan and vegetarian diets have “reduced GHG emissions over standard omnivorous diets in a wealthy context.” When it comes to other types of environmental impact, LCA studies have shown that decreasing one’s animal consumption “reduces all accounted environmental impacts, reduces particulate matter formation and land occupation or, conversely, exacerbates water consumption.” In other words, according to these authors, while LCAs have consistently shown that veg*n diets have a positive impact on GHGs, there may be some negative consequences too.

This study examined veg*n diets using the LCA approach, but also attempted to look beyond GHGs as the most important (or only) measurement of impact. The researchers note that “the common application of single issue indicators, chiefly the GHG burdens, dominates relevant literature.” To try to rectify this, they examined the methodology behind the LCA and analyzed data from The Netherlands to make their conclusions. They describe how LCAs account for “exchanges (resource consumptions, energy, pollutant emissions) between different, well-defined environmental compartments (water, land and air in their different permutations) and the system (herein the ‘product-system’) providing the functional unit.” In this case, the functional units are food products ranging from meat and dairy to vegetables.

What they found is that the LCA generally supports the existing evidence that low-meat or veg*n diets are positive for the environment, but one point of departure is the exception of water scarcity, “which was influenced by the higher grain, fruit, and vegetable intake of these diets.” They also note that “following vegetarian or vegan diets should not be conflated with sustainable lifestyles.” They conclude by saying that “one can adhere to a low meat diet while causing negative environmental impacts in other aspects of life (e.g. commuting long distances by private vehicle, frequent air travel, large dwelling, etc.) that more than negate the positive environmental impacts of food choices.”