Making Veganism go the Distance in Environmentalism

Researcher Network member, Robin Struber, looks into the environmental impact of our diets

Veganism is increasingly seen as a vital lever to sustainability. Assessing the impact of our foods is complex but understanding the core ingredients and processes allows us to make educated decisions on what we eat. Here are some things to look out for to understand the carbon in our diets.

Adopting a vegan diet is a growing global shift, in the UK alone there are about 2.5 million vegans in 2024.[1] So too the reasons for joining the cause are more diverse than ever before. Particularly among Gen Z, environmentalism is named in the same breath as animal rights and nutritional benefits for switching to veganism. This makes deepening our understanding of how to effectively decarbonise consumption patterns through a vegan diet a timely, albeit challenging, undertaking. The food and drink sector is historically slow to respond to external change. It is generally considered an incremental innovation sector, so pressure from consumers to demand change is paramount. The food and drinks industry accounts for more than a third (34%) of global greenhouse gas emissions through food production, logistics and waste,[2] so continuing the increasing trend towards vegan nutrition and reducing consumption of animal products is an important step for change. How then can veganism go the distance in maximising environmental gains? 

The good news is that making the switch to any form of plant-based diet has a demonstrable positive effect! Even the most resource intensive plant-based protein consumes less water, energy and produces fewer carbon emissions than animal products.[3] On average plant-based options have half the carbon impact of products with animal origin: 4,963 TgCO2eq. compared to 9,923 TgCO2eq.3 For new adopters this means maintaining similar consumption patterns and recipes but replacing ingredients of animal origin with analogues, which can remove the biggest environmental culprits without having to affect behavioural change. However, there are significant differences in ecological footprint between vegan protein sources, from wholefoods to minimally processed products such as tempeh and tofu, all the way to ultra-processed plant-based meat analogues. So, spending some time understanding the various environmental profiles of what you eat can be helpful both for new adopters and seasoned vegans.

To do this it is helpful to not just consider greenhouse gases, but also how much water and energy are consumed since most is still generated by unsustainable sources, thus contributing towards environmental degradation. Across these three dimensions, 71% of the carbon impact and more than 90% of water usage is directly attributed to land use and land change activity while processing consumes most of the energy.[4] Considering airmiles and packaging is definitely important, but the biggest impact can be had by understanding the ingredients and processing involved in the products we put in our supermarket baskets. Of these, the most common vegan protein sources are legumes (soy, peas or lupine), grains such as oats or wheat, mycoprotein (a form of fungi) and nuts.

Legumes, especially peas, have the lowest carbon impact on average ranging from 0.2-0.6 kgCO2eq. while cereals are in the range of 0.3-1.0 kgCO2eq.[5] Furthermore, legumes need less area to grow so have a low land use impact. Many researchers consider peas the most promising plant-based protein to adopt into our diets. Its use is not yet widely adopted however, because its biomass is harder to manipulate than soy and wheat, so may require a bit of searching to find during your shop. On the other hand, low processed pea protein works in your favour when minimising environmental effects! Soy meanwhile is common across many analogue meats or plant-based products and has a relatively similar profile to peas.

Another ingredient easily found, particularly in the UK, is mycoprotein. Compared to legumes and cereals however, mycoprotein requires comparatively high levels of energy and high-quality raw materials such as sugars to create large volumes of biomass so it ranks last in comparative studies for energy efficiency.5 As a positive, the land use needed to create biomass is extremely low for mycoprotein. Unfortunately, there is very little research to quantify the impact of nuts and rarer forms of protein such as pseudocereals (chia and quinoa) however we know that these consume a great quantity of water for comparatively little biomass and have an estimated carbon intensity of 2.1 kgCO2eq.kg−1,3 so may not be as desirable as a primary protein source in vegan diets.

For mock meats the less processing involved the better. As a result, sausages and burger patties have the highest environmental impact with an average of 2.79 kg CO2eq.kg−1, while dried mince has the lowest among analogues with only 1.33 kgCO2eq.kg−1.4 Furthermore, frozen products have a higher impact due to the energy intensity of nitrogen or other freezing processes. Thus, heading to the fresh food and refrigerated section instead of the frozen food aisle is preferable. Processing roughly adds 9-23% of carbon emissions onto ingredients so while wholefoods generally have less of an ecological footprint, using vegan mince or burgers to make your recipes work can still significantly reduce your carbon footprint compared to conventional diets.4 It is also important to recognise that the plant-based market is still in its early stages of innovation with great potential to further improve efficiency and environmental gains through more efficient processing.

In summary, the most important step you can take is to throw out traditional meat products for vegan alternatives. Our diets will always come with a carbon price tag so focussing on products whose processing and growth is efficient is the easiest path to minimise our impact on the environment. If you don't want to give up on your tried and tested recipes, or simply have a consistent ingredient for protein intake, plant-based analogues may come with somewhat higher associated carbon footprints compared to legumes but still reduce individual carbon footprints compared to an omnivorous diet. Looking out for products with base ingredient legumes such as peas and soy can ensure you have the highest environmental reduction though mycoprotein has a low land use so still benefits the environment. Importantly, remember that exploring different vegan alternatives is meant to be an enjoyable process!