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Are modern plant-based diets and foods actually sustainable?

April 15, 2018
Helen Breewood

This post is written by Helen Breewood, research assistant at the FCRN. She is also a freelance writer, and blogs about solving global sustainability issues at The Progress Motive. You can find her on Twitter. She is writing this post in her personal capacity. Note too that the FCRN has no financial affiliation with any of the brands mentioned in this blog.

Cover image: tookapic, Avocado vegetable cut, Pixabay, Pixabay Licence

Vegan food is in fashion, and not just among the increasing numbers of vegans - many Brits are cutting down their meat intake, in a trend known as flexitarianism. As a vegan living in the UK, I’m noticing a lot of changes: supermarkets and restaurants are cashing in by offering new vegan options, Instagram is bursting at the seams with avocados and colourful Buddha bowls, and bloggers such as Deliciously Ella are making plant-based foods mainstream. This new-found popularity of vegan foods has been hailed as great news for the planet - but might these changes have unintended consequences? How much do we really know about the environmental and social sustainability of modern plant-based eating?

Total diet impacts

Modern supermarkets offer fresh produce all year round and have an increasing variety of vegan ranges. A few decades ago, vegans might have had more limited options: seasonal vegetables, grains, lentils, tofu. Do studies looking at the environmental impacts of various dietary patterns account for the far wider range of vegan choices that are available nowadays?

One study (Scarborough et al., 2014) calculated the greenhouse gas emissions caused by the self-reported diets of meat-eaters, fish-eaters, vegetarians and vegans in the UK, and concluded that vegan diets have around half the emissions of omnivorous diets. However, while the database of food emissions that the study used does include vegan protein sources such as soybeans and other pulses, it doesn’t appear to include several alternatives such as some nuts and seeds, tempeh, tofu, mycoprotein (used to make Quorn) and processed meat replacements. Perhaps more importantly, the dietary data was collected in the 1990s and may not reflect the composition of current diets, vegan and otherwise. Many products available now simply weren’t around then, such as Quorn’s vegan range (regular Quorn contains egg white).

Another study using more recent consumption data from Italy (Rosi et al., 2017) found that, on average, vegan diets in the study sample had lower carbon, water and ecological footprints than omnivorous diets. However, there was a lot of variability between individuals. Some vegans had higher dietary impacts than some omnivores. Two vegan participants had extremely high dietary impacts, on par with the highest impact omnivorous diets - it turned out that they ate only fruit!

Veganism is clearly not an inherent guarantee of eco-friendliness. Personally, since environmental concerns were the main reason I switched to a vegetarian diet 11 years ago and to a largely vegan diet a couple of years ago, it’s worrying to think that I could inadvertently be choosing high-impact foods. Here are a few issues that I would love to see more information on.

Palm oil

Image: T. R. Shankar Raman, Land cleared for oil palm plantation in Sabah, Borneo, Wikimedia Commons, Creative Commons Attribution-Share Alike 4.0 InternationalImage: T. R. Shankar Raman, Land cleared for oil palm plantation in Sabah, Borneo, Wikimedia Commons, CC BY-SA 4.0

Nowadays, there are many plant-based replacements for dairy products such as butter, ice cream and cheese - Tesco and Sainsbury’s have even developed their own vegan cheeses. But I’ve often spent a long time puzzling over which brand to buy, if any. Besides having questionable nutritional value - many dairy alternative brands are high in fat with little protein - it’s very difficult to avoid palm oil.

Palm oil plantations cause deforestation and push species such as the orangutan further towards extinction. So which causes more animal suffering and biodiversity loss - dairy farming or palm oil induced deforestation?

Some brands do contain a “sustainable” certified version of palm oil. For example, Unilever, who make the vegan ice cream Swedish Glace, claims to be taking steps towards responsible palm oil sourcing, as does dairy-free spread manufacturer Pure Free From.

But does certification actually reduce overall rates of deforestation, or does it just shift the blame to other, uncertified, producers? Might the availability of “sustainable” palm oil actually increase overall market demand for palm oil, or encourage different crops to be grown on deforested land? Greenpeace claims that the Roundtable on Sustainable Palm Oil’s standards still permit deforestation and peatland destruction. Further complicating the issue, replacing palm oil with other fats such as olive or sunflower oil wouldn’t necessarily be a sustainable solution, since these crops use 5 to 8 times as much land as palm oil to produce a given quantity of oil or fat.

Coconut oil

Coconut oil is another ingredient found in many dairy replacements. It’s also popular with the paleo and clean eating movements (although it may now be losing ground to butter and ghee).

Could coconut oil cause deforestation in the same way as palm oil? Ethical Consumer says that deforestation isn’t a serious issue with coconut farming, but that producers are often in extreme poverty. While Fairtrade coconut products are available, a 2014 study by SOAS and the LSE concluded that the benefits of Fairtrade are debatable, particularly for the poorest workers - although the Fairtrade Foundation itself has contested the study’s findings.


Tofu has been around for a long time – possibly thousands of years – and now soy beans appear in all sorts of products. However, soy production increased ten-fold between 1961 and 2009. Nowadays, soy plantations wreak havoc upon the environment, causing deforestation and soil erosion. In Argentina, the appearance of a new river has been blamed on soybean plantations.

75% of soy is actually used to feed animals. Since feeding an animal with soy gives you less food value measured in calories or protein than eating the soy directly, is it reasonable to assume that demand for soy would actually drop as the popularity of soy-based foodstuffs rises, because of reduced demand for meat?

The FCRN-WWF report* How Low Can We Go? makes a rough estimate that, in the UK, replacing UK-produced beef and sheep meat with tofu, Quorn and pulses (in proportions of 20%, 20% and 60%, respectively) would require more overseas land while reducing arable land use in the UK (see Table 39 of the report). This is partly because substitutes such as soy, chickpeas and lentils are generally not grown in the UK and partly because some of the chosen pulses (lentils and chickpeas) have low yields per hectare. As the report notes, choosing higher-yield pulses could reduce the overseas land required. While using more land overseas, the substitution of ruminant meat with alternatives could free up some arable land in the UK previously used to grow feed crops. Perhaps the answer is to grow more pulses in the UK, such as broad beans, dried peas or haricot beans. For more on this option, see the blog post that Tom Kuehnel of The Vegan Society wrote for the FCRN.

The FCRN-WWF report also estimates the land required for pig and poultry meat and their substitutes. Table 29 shows that the arable land needed to produce feed crops for UK-raised pig and poultry meat is 1,109 kha in the UK and 968 kha elsewhere (note that the model used for land use calculations does not attribute any grassland to the production of pig or poultry meat in the UK – see Table 28). Table 38 shows that substitutes (soy, other pulses and sugar to cultivate Quorn) for UK-raised pig and poultry meat would use 659 kha of land in the UK and 2,946 kha of land elsewhere. This suggests that replacing UK-produced pig and poultry meat with substitutes would reduce UK land use and increase overseas land use.

Taking a global perspective might give a different answer, as other countries might rely on different mixes of grass-fed, grain-fed or soy-fed livestock. There might also be differences in the growing conditions of soy for animal feed and human food. For example, food-grade soybeans are higher in protein than feed-grade and require more careful processing to ensure that weeds don’t contaminate the harvest - does this change their environmental impact?

These are important questions. Are they adequately addressed by brands that use soy beans?

Alpro say they use soy beans that are certified by the ProTerra standard, which requires non-GMO beans, good labour practices, protection of community rights and specific agricultural practices related to soil fertility, water management and reduced inputs of fertilisers and pesticides. Alpro also source some of their soy beans from European countries and are developing varieties suited to the climates of France and Belgium.

Other brands, however, are less specific. Tofoo, for example, say they use organic beans and draw attention to their “all-natural” ingredients, but haven’t replied to an email requesting their sustainability policy at the time of writing this blog post. Meanwhile, Cauldron Foods say that their soy beans, grown in Canada, China and Europe, are sourced from “strict sustainable areas where the beans must be grown in ways that are organically, ecologically and ethically good”, but don’t explain exactly what this means. Clearspring don’t mention sourcing policies at all in their environmental standards.

Processed meat replacements

Image: Lemon and Chilli Linguine with Quorn Meat Free Pieces, Quorn Recipes Press Pack.Image: Quorn, Lemon and Chilli Linguine with Quorn Meat Free Pieces, Quorn Media Centre

How sustainable are highly processed meat replacements?

Perhaps the best-documented brand is Quorn, which is based on mycoprotein. A simplified life cycle assessment report from 2010 (the author of that study currently works at Quorn, but it’s not clear whether this was an official Quorn publication) estimated that two vegetarian Quorn products (mince and pieces) have a slightly higher carbon footprint than poultry but considerably less than beef. Removing the egg in the formula (used to bind the ingredients) would halve Quorn’s emissions, but data showing the impacts of Quorn’s more recently produced egg-free vegan range are not available.

However, Quorn’s official 2017 Sustainability Report claims that Quorn mince has a carbon footprint 90% lower than beef, and that Quorn pieces have a carbon footprint 70% lower than chicken. Since the document cited for these figures is not publicly available, it’s not possible to check why they don’t tally with the earlier study. I emailed Quorn to see if they could provide the reference for these figures and an estimated carbon footprint for their vegan range. They said they would look into it but haven’t been in touch since then. [Edit, April 2020: Quorn have now published a Carbon Footprinting Emissions Report (PDF link) and a 2018 Quorn Footprint Comparison Report (PDF link), certified by the Carbon Trust. These show the following carbon footprints, measured from farm to factory gate: 1.2 kg CO2 eq./kg Quorn mince (which contains egg); 1.2 kg CO2 eq./kg Quorn pieces (which also contain egg); and 1.4 kg CO2 eq./kg Quorn vegan pieces. Quorn cites average farm-to-factory-gate carbon footprints of 27 CO2 eq./kg for UK beef and 5.9 CO2 eq./kg for UK chicken. That would mean that Quorn mince has a carbon footprint 95% lower than UK beef, and that Quorn vegan pieces have a carbon footprint 76% lower than UK chicken, when measured from farm to factory gate.]

Linda McCartney Foods and The Fry Family Food Co. who make meat replacements based on soy and wheat protein, both told me by email that they don’t have environmental impact data for their products.

Estimating the impacts of other meat replacements is not as simple as just adding together the impacts of the individual ingredients (often soya and wheat gluten), because of the importance of processing to the overall environmental impact of a given product. For example, culturing mycoprotein accounts for only 46% to 55% of emissions per tonne of Quorn, with the processing stages accounting for the rest. Are processing impacts similar for other meat replacements, and how do they compare to the impacts of processing meat?

The 2015 paper Meat alternatives: Life Cycle Assessment of most known meat substitutes finds that, in general, lab-grown meat and mycoprotein-based substitutes have higher environmental impacts than chicken, dairy and gluten-based substitutes, and that insect and soy-based substitutes have the lowest impacts of all. Clearly not all of these are vegan, including the mycoprotein option (assumed to contain egg). Variations between brands and future technological developments are likely to lead to variations in impacts.


Image: GroCycle Urban Mushroom Farm, GroCycle NewsroomImage: GroCycle Urban Mushroom Farm, Grocycle press kit

Mushrooms have been in the news lately: the World Resources Institute, a US NGO, estimates that replacing 30% of the beef in beef burgers with mushrooms could reduce the water use, greenhouse gas emissions and land use of a burger by 29-30%. The advantage of these blended burgers is that they reduce impacts without requiring large lifestyle changes from consumers.

Mushrooms grow well on substrates that are byproducts of other processes, such as straw, sawdust, manure and even used coffee grounds. How many commercial mushroom farms actually use byproducts and how many use substrates produced specifically for mushroom growing? If demand for mushrooms were to rise, how would supplies of substrates need to change? And how, in turn, would that affect the environmental impacts of mushroom growing? I guess that many cafés still throw out their coffee grounds, perhaps providing an opportunity for more companies such as GroCycle’s Urban Mushroom Farm. However, there are logistical constraints: the coffee grounds need to be used very quickly, or else they go mouldy. Besides, would it be efficient, from the point of view of energy, to collect small amounts of coffee grounds from many cafés? GroCycle does collect coffee grounds by bicycle, but would this be true of other producers?

Another issue is that some mushroom farms use peat. As you may know if you are a gardener, peat extraction can damage peatlands, which are important wildlife habitats and stores of carbon.

Mushrooms don’t need light, so they can be grown in stacked layers without needing artificial lighting, but farmers do carefully control the air temperature and humidity to influence the size of the mushrooms. How much energy does this require?

Life Cycle Assessments are available for some commonly grown mushrooms, but do they cover all of the different types of mushrooms now on the market, and all different growing conditions and countries? For example, what about mushroom types that prefer to be grown on solid logs and take longer to mature and fruit than those grown on sawdust? What are the impacts compared to the foods that mushrooms might be replacing?

Imported fruit

Fruit isn’t just for vegans, but could a rise in veganism stimulate an increase the amount of fruit being consumed? What effects might that have?

Some fruits are now particularly popular with vegans and omnivores alike, or are finding new popularity through vegan recipes.

Take the iconically Instagrammed avocado. Avocados have been associated with illegal deforestation in Mexico, high water use in California and Mexico, questionable working conditions in many Latin American countries and trade controlled by drug cartels in Mexico.

What about fruits that are only recently becoming well-known in this country, such as the jackfruit - used to make mock “pulled pork”? A quick search for the environmental impacts of jackfruit doesn’t yield much useful information. Could it be that jackfruit doesn’t cause any problems? Or are the problems there, but hidden?

Bananas are practically a staple in supermarkets. They are also the basis of some delicious vegan recipes, such as this ice cream. While bananas are fairly low-carbon since they are grown in hot countries (and therefore don’t need to be grown in heated greenhouses) and are transported by container ship, there are serious questions over working conditions in the industry, as well as the vulnerability of banana plantation monocultures to disease.

With fresh produce, it could be helpful for shoppers to know which fruits have been air-freighted (very carbon intensive) or transported by container ship (relatively low carbon). Supermarket labels often give country of origin but rarely give the transport method. Since local food is not necessarily more sustainable, e.g. due to the energy used to heat greenhouses in the UK, transport information could be crucial when trying to choose the lowest carbon option. Tesco and Marks & Spencer did actually try this in the early 2000s, but found the labels had no effect on sales - but might similar schemes succeed now that consumers are more aware of climate change? Furthermore, what would the effects of such a scheme be on employment and economic development in low-income countries?

Water use

Image: Suzi Rosenberg, IMG_2207 Almond orchard around February, Flickr, Creative Commons Attribution 2.0 GenericImage: Suzi Rosenberg, Almond orchard around February, Flickr, CC BY 2.0

Avocados aren’t the only product to use a lot of water. Almond milk, for example, may have a carbon footprint 10 times less than dairy milk, but it uses 17 times more water than dairy, according to one study. And as a recent study showed, almond milk is not nutritionally equivalent to dairy milk. With many almonds grown in California, which has only recently emerged from a drought, this could be a problem. One potential alternative is pea milk, claimed by its US makers Ripple to use much less water than almond milk. Ripple is not on sale in the UK, at the time of writing.

Dates are well suited to growing in dry regions, but in some areas there are politically charged issues of access to water.

What about other widely used vegan ingredients? The World Resources Institute’s interactive map of water stress shows that 50% of tree nuts, 38% of fruit and 32% of legumes are grown in areas of high or extremely high water stress. Of course, this doesn’t mean that vegan diets are necessarily to blame - these products are eaten by people following all sorts of diets, as well as sometimes being used as animal feed. Nevertheless, it will be important to watch the overall environmental effects of increases in the human consumption of these crops and corresponding declines in demand for animal products.

Economic effects

Image: Michael Hermann and Crops for the Future, Quinoa farmer in Cachilaya, Wikimedia Commons, Creative Commons Attribution-Share Alike 3.0 UnportedImage: Michael Hermann and Crops for the Future, Quinoa farmer in Cachilaya, Wikimedia Commons, Creative Commons Attribution-Share Alike 3.0 Unported

Demand for quinoa has driven up prices to the point where many poor Peruvians and Bolivians can't afford it, although it was a staple food for many. What are they eating instead, and is it more or less sustainable and healthy than quinoa? Do the economic benefits to the farmers outweigh the price swings? What other crops have risen in price due to popularity, and how are the economic effects changing global consumption patterns? How will changing markets drive investment and government policies?

Potentially lower-impact foods

While the foods I’ve listed above may raise a few alarm bells or at least question marks, it’s not all bad news. There are many trendy vegan foods that I think are likely to have low environmental impacts. Kale, for example, is popular on Instagram, but unlike the avocado it can be grown in the UK in winter. Aquafaba - the leftover liquid from a can of chickpeas - would normally go to waste, but has lately found popularity as an egg replacement for baking, mayonnaise and even chocolate mousse. One of my favourite recipes for cheesy pizza topping is based on potato, carrot, olive oil and nutritional yeast: it doesn’t use as much oil as many store-bought vegan cheeses and uses vegetables that are easy to grow in the UK. However, the environmental impacts of nutritional yeast are not clear. Producers Marigold Health Foods told me by email that the yeast is fed on beet molasses. Although they said that they expect that it has a low carbon footprint, they don’t have any evidence to prove it.

What do you think?

Personally, I am glad that vegan foods are becoming more popular, but there are many knowledge gaps. What do you think? Please do add your thoughts and feedback in the comments section below. What issues need to be explored most urgently for us to assess the impact of changing vegan diets and what needs to be done to address any downsides?

Would you like to write a blog post for the FCRN? We’re always happy to hear your ideas. Get in touch here.


*This article was edited on 29 June 2020 to cite specific tables from the FCRN-WWF report How Low Can We Go?, to make it clear that the estimate from Table 39 is for UK-produced ruminant meat only and to separately discuss the report's findings for pig and poultry substitutes. 


Donal Murphy-Bokern's picture
Submitted by Donal Murphy-Bokern (not verified) on

I only want to comment on one part of this article.  It report that the FCRN-WWF How Low report said "that, at least for the UK, replacing beef, sheep, pig and poultry meat in our diets with tofu, Quorn and pulses could actually increase the amount of overseas land needed." 

This is not accurate.  The said report (Audsley, E., Brander, M., Chatterton, J., Murphy-Bokern, D., Webster, C., and Williams, A. (2009).  An assessment of greenhouse gas emissions from the UK food system and the scope for reduction by 2050.  How low can we go?.  WWF-UK and the FCRN) notes that a switch from (UK-produced) beef and milk to highly refined livestock product analogues such as tofu could actually increase the quantity of arable land needed to supply the UK.  This is simply because for a given amount of protein, the soy use in tofu is greater than the soy use for UK-produced beef or milk.  This does not apply to all meat as this article suggests.

Helen Breewood's picture
Submitted by Helen Breewood on

Hi Donal,

Thanks for your input. Here's what the report How Low Can We Go has to say, if I have understood it correctly.

Table 39 estimates that replacing ruminant meat (beef and sheep) with Quorn, tofu and pulses (in proportions of 20%, 20% and 60%, respectively*) would reduce arable land use in the UK by 11 kha, reduce "arable-forage" land use in the UK by 837 kha and increase overseas arable land use by 1,218 kha.

Table 40 estimates that replacing milk with dairy analogues (based mostly on soy and rapeseed oil) would reduce UK arable land use by 80 kha, reduce UK arable-forage land use by 1,272 kha and increase overseas arable land use by 226 kha.

So, as you say, switching from ruminant meat and milk to the alternatives modelled here decreases UK land use and increases overseas land use.

Moving on to the other meats, the report does not explicitly discuss the land use change effects as for the products above, but it does give the following information.

Table 38 shows that the substitutes for pig and poultry meat altogether use 659 kha in the UK and 2,946 kha overseas, while Table 29 shows that the land needed to produce arable crops to feed UK-produced pig and poultry together is 1,109 kha in the UK and 968 kha overseas. This implies that switching from pig and poultry meat to the alternatives modelled would increase overseas land use.

That is why I have said that overseas land use would increase if all of these meats were replaced with the alternatives. I'd be glad to know if you think I have misinterpreted this.


*This comment was edited on 29 June 2020 to correct the proportions of Quorn, tofu and pulses.

Sam 's picture
Submitted by Sam (not verified) on

Good article Helen, thanks. 

I might be able to shed some light on the mushroom side of things, having recently toured a hi-tech G's Fresh site in Peterborough. The inputs struck me as relatively emission-intensive - at least more so than expected: the spawn comes from America every time as mushrooms are prone to mutate and with every generation removed from mother-line, you risk mutations compromising quality and food-safety. The spawn goes to Belgium where it is used to populate organic straw manure from a horseu livery (it's hard to find the exact, specific substrate apparently), and this is trucked over to the UK. The compost is then covered with 6cm of (sustainably sourced) peat. Growing is hi-tech, with conditions closely monitored and manipulated, and turnaround is quick - 3 flushes, which yield 3 different grades within 6 weeks. Then everything is turfed out and start again. The residue is composted and used elsewhere on the farm, and heating is provided by nearby anaerobic digester (alebit fed on specifaclly grown maize feedstock). It's also a very chlorine intensive process, as conditions are favourable for moulds etc, and controlling hygiene is important.

That's my first-hand input. I think it's easy to push the problem around the world, and you're safest to eat locally and seasonally in order to avoid excessive emissions. The UK, if you look at the soft-fruit market, is getting better and better at extending the season and reducing food imports.  

Helen Breewood's picture
Submitted by Helen Breewood on

Hi Sam, that's really helpful - thank you! Can I ask what you mean by sustainably sourced peat? I wonder whether it has the same question marks as "sustainably" sourced palm oil. What do you think of business models such as GroCycle's (growing mushrooms on used coffee grounds)? Is it feasible to scale up that production method, or is it unlikely to be competitive? I was surprised to find out that the inoculation of the substrate is not done on the farm - it must add a fair amount of transport emissions. I wonder whether it's possible for the compost residue to power the anaerobic digester, rather than growing maize specifically for heating. Does even the edible part of the maize get used to provide heat, or just the stalks and by-products?

Domi's picture
Submitted by Domi (not verified) on

It's really good to see an article on this important issue. Many of us these days make an effort to be more environmentally-friendly - we take shorter showers, always switch the lights off, and try to cycle or use public transport instead of driving.

But many people who claim to care about the planet can’t see the wood for the trees, and don’t realise how devastating animal agriculture is to natural environment; a “meat-eating environmentalist” is as much of an oxymoron as “ethical slaughter”.

There is no such think as a meat-eating environmentalist - those who care about the planet should put their words into action by going vegan!

Helen Breewood's picture
Submitted by Helen Breewood on

Hi Domi - thanks for your comment. While I personally think that the vegan diet is generally the best option, on a global scale, for reducing carbon emissions, and while I also think it's ethically preferable to avoid animal slaughter where possible, I also expect that there will be regions of the world where it's not practical or environmentally feasible to eat a purely plant-based diet. 

KarlW's picture
Submitted by KarlW (not verified) on

That's a superb, well-balanced piece of writing Helen, thank you.

I find myself in this debate frequently. As the message to shift to a plant-based diet seems to be gaining popularity, I get into many conversations with people who have adopted the message "eat less meat to 'save' the environment." While I applaud the individuals making this choice because they believe, ethically, that it is the right thing to do, I am worried that the mesage is misguided. Personally, I don't think the message should be to eat more or less meat, more or less fish, more or less grains, more or less fruit, more or less veg...because the precise make-up of a person's diet will [should] vary with geography and season. The message should be 'eat more sustainably farmed food' rather than 'eat less meat'.
Of course, if eating meat means eating feedlot beef then yes, 'go vegan' is a better message - for the environment, and for animal welfare. But in other scenarios, it's far less clear. There is a farm less than one mile from my house, with a butcher and farm shop on site. I can see the lambs in the fields from my upstairs windows, I see them all days, all weathers, eating grass. I go to the shop, with my young kids, we feed them spring dandelions through the fence, then go in the shop and purchase lamb.
In the same shop, we can purchase bananas from Costa Rica, that are not stamped Fairtrade.
Farming lamb is perfectly suited to much of the English countryside, and those sheep only leave the farm once in a lifetime, for the short journey to a high-ethical-standards slaughterhouse, and then the meat returns to be butchered on site.
I can buy organic, grass-fed, outdoor-reared, high-ethical standard lamb with a remarkably low carbon footprint, while eating seasonally, supporting local businesses, building my relationship with my local butcher and teaching my kids about where food really comes from...or I could buy more bananas from five and a half thousand miles away, where I am completely unaware of how the farm workers are being treated, or if the banana plantation uses any external chemical inputs.
I think the lamb is the right choice - ethically, environmentally, and for sustainability.

But I wholly recognise that in another scenario, depending on season, climate, geography, economics, lamb may be the worst possible choice, and tofu or chickpeas or bananas may be perfect. Context is everything.

I believe the message we need to be trying to share with the public, is to shift to a diet that meets our nutritional needs, but is sustainable from an environmental point of view, and is based on high ethical standards in farming. Those buying in to the messsge to 'eat less meat' need to understsand that the billions of insects and bugs living in the soil, are an important as the large animals with big brown eyes. I often say "If people eat less meat, what else are they going to eat more of instead?" - because if the answer is more methane-emitting rice, more soil-eroding monocrops, more highly-processed factory food products, then we are not moving towards sustainability, and we are not solving any of our ecological problems. We're just saving a few cows, at the expense of good human nutrition.

Again, thanks for a great piece.

Helen Breewood's picture
Submitted by Helen Breewood on

Thank you so much for your comment. I agree that context is very important, and that there are many different sorts of production systems with different impacts. However, I must take issue with your suggestion that organic, grass-fed lamb has a "remarkably low carbon footprint".

In my MPhil thesis (PDF link) I compared the environmental impact of various different meals prepared in a canteen. I examined chicken and several alternatives. Table 73, in the row "Agriculture, chicken or replacement" gives the carbon dioxide equivalent emissions associated with the agricultural stage of the meat or alternative (see Table 9 for scenario descriptions): 0.47 kg CO2 eq. for non-organic British chicken per meal, 0.69 for organic British chicken, 1.54 for non-organic British beef, 0.69 for non-organic British pork, 1.46 for non-organic British sheep meat (lamb and mutton were considered together in the data source), 0.01 for non-organic French canned faba beans (i.e. mature broad beans) and 0.17 for non-organic French sunflower seeds. All were compared on the basis of equal weights of servings, which is not ideal from a nutritional point of view, but still shows a difference of orders of magnitude between the beans or seeds and the sheep meat. Faba beans can be grown in the UK, unlike most soy.

These figures reflect national averages and might not be the same as purely grass-fed systems. The data source I used (Williams et al., 2006, "Determining the environmental burdens and resource use in the production of agricultural and horticultural commodities") shows in Table 57 that organic sheep meat has a 42% lower carbon footprint than non-organic (this is not a general rule for meat: organic poultry has a higher carbon footprint than non-organic). This would put the emissions for the organic sheep meat agriculture stage at around 0.62 kg CO2 eq. per meal (only approximately, since my model included a few other factors) - still higher than non-organic chicken and far higher than faba beans or sunflower seeds.

(Incidentally, the same study shows that tomatoes grown in a heated British greenhouse have much higher carbon emissions than Spanish tomatoes grown in unheated greenhouses - and my thesis shows that the difference far outweighs the extra transport needed, at least from the point of view of carbon emissions.)

This study claims that the carbon footprint per kg liveweight of lamb produced in England and Wales is around 10.85 kg CO2 eq. for lowland production, 12.85 kg CO2 eq. for upland production and 17.86 kg CO2 eq. for hill production. Since only around half of that will be edible meat, then the carbon footprint could essentially double if you allocate all of the emissions to the edible portion: so around 36 kg CO2 eq. per kg of hill-raised lamb. 

​For comparison, the paper Systematic review of greenhouse gas emissions for different fresh food categories​ gives approximate carbon emissions as follows: legumes and pulses 0.66 kg CO2 eq. per kg, rice 2.66 kg CO2 eq. per kg, tree nuts 1.42 kg CO2 eq. per kg, cereals 0.53 kg CO2 eq. per kg, chicken 4.12 kg CO2 eq. per kg, lamb (world average) 27.91 kg CO2 eq. per kg bone-free meat, beef (world average) 28.73 kg CO2 eq. per kg bone-free meat. A figure from the paper shows a wide range of emissions, but lamb does fall well towards the high-impact range of the spectrum:

I would be interested to see if you have any different data on lamb having low carbon emissions.

It's also highly debatable whether extensive sheep farming is actually well-suited to the British countryside. George Monbiot, for example, is particularly outspoken about the lack of biodiversity on sheep-grazed hills, as well as the potential for making flooding worse by not allowing trees to grow.

Thank you again for taking the time to respond to this piece.

John Kay's picture
Submitted by John Kay (not verified) on

A quick online search revealed these ingredients -

Imitation milk: Water, hulled Soya Beans, dipotassium phosphate, monopotassium phosphate, calcium carbonate, "flavourings", sea salt, gellan gum, vitamins B2, B12, D2

Imitation meat: Pea protein isolate, canola oil, refined coconut oil, water, yeast extract, maltodextrin, “natural” flavourings, gum arabic, sunflower oil, salt, succinic acid, acetic acid, modified food starch, bamboo cellulose, methylcellulose, potato starch, ascorbic acid, annatto extract, citrus fruit extract, glycerin, beetroot juice extract.

Pasture-fed milk and meat: Water, grass, herbs

Helen Breewood's picture
Submitted by Helen Breewood on

Hi John - thanks for commenting. The notion of synthetic food is certainly an important issue for many consumers. Eating "meat replacements" is certainly not the only approach to a vegan diet. Many plant-based dishes use relatively unprocessed foods - lentil curry, for example, or a rice, vegetable and cashew nut stir-fry. I think that the benefit of highly processed meat replacements is that they make it easier for people to adapt to a plant-based diet, since the replacements can be cooked in a similar way to the meat-based recipes that many people know. Plant-based cooking often takes some getting used to as it does not always rely on a high-protein centrepiece, but rather often puts together several ingredients that are less protein-intensive to make a nutritionally balanced meal overall - for example, chickpeas and couscous.

Annette Burgard's picture
Submitted by Annette Burgard (not verified) on

Hi Helen, 

great article, thanks a lot for going into detail on lots of these topics. 

One topic that IMO should get more coverage is that of a 'balanced diet'. I'm environmentally motivated, same as you. From all my own research I've concluded that the issue with animal agriculture is not so much that we eat animals, but that we eat so much meat, and of so few species. It's a bit frustrating to see that we seem to be on the way to making the same mistakes again when it comes to meat-replacements and plants. The assumption that we can feed the majority of the human population with less than 20 'ingredients' just doesn't make sense (According to the FAO today 75% of our food comes from 5 species of animals and 12 plants). The world has evolved as an eco-system with lots of variety and that seems to be the best (or possibly only?) way to achieve a sustainable diet. It comes at the cost of convenience, which we price so highly these days. It seems that less focus on so few ingredients would solve the majority of the problems you describe. 

Would love to hear your thoughts about that. 

Annette (

Helen Breewood's picture
Submitted by Helen Breewood on

Hi Annette,

Thanks for your comment! I agree that agrobiodiversity is a hugely important issue. There are risks associated with relying on so few strains, as I'm sure you know: the strain of banana commonly used a few decades ago, Gros Michel, was almost wiped out by a type of fusarium wilt - but the strain that replaced Gros Michel, the Cavendish widely used today, could go the same way if a new strain of fusarium wilt spreads. I'm sure other crops face similar risks. 

I also wonder about the nutritional implications: would a greater variety of plants make it more likely that people get all the nutrients they need, since each plant could extract a different profile of minerals from the soil and produce different vitamin profiles?

We might also need more crop variety to enable crops to adapt to climate change.

The plant varieties that are favoured for ​ease of shipping and transportation might not be the same as the best tasting or most nutritious varieties.

I believe (but correct me if I'm wrong) that one of the reasons that monocultures are favoured is that it makes it easier for farmers to use large-scale, mechanised agricultural methods, since all the plants are the same and probably ripening in a short timeframe. That make me wonder whether agricultural polycultures, where several different species are grown together, or growing many different crops in many small fields, would be less efficient from the point of view of energy use? Would we need more human farm workers instead of using large tractors? Would that send food prices up? Or could advances in lightweight farm robotics make it feasible to harvest a variety of food types in one field without using much energy?

If you know of any research that links crop variety and overall environmental impacts, I'd love to see it.

Thanks again for commenting!

Helen Breewood's picture
Submitted by Helen Breewood on

Many thanks to FCRN member Peter Alexander for bringing to my attention some of his relevant research.

Alexander, P., Brown, C., Arneth, A., Dias, C., Finnigan, J., Moran, D., Rounsevell, M., 2017. Could consumption of insects, cultured meat (i.e. lab-grown meat) or imitation meat reduce global agricultural land use? Global Food Security 15, 22–32. doi:10.1016/j.gfs.2017.04.001

This paper investigates the global agricultural land use changes associated with replacing conventional meat with cultured meat, imitation meat (i.e. analogues such as tofu or Quorn) or insect-based food. It finds that imitation meats and insects have the highest land use efficiency, although they use only slightly less land than poultry and eggs, while cultured meat uses around the same amount of land as poultry and eggs.

The figure below shows the land use impacts of replacing 50% of current nutrients from animal consumption with the indicated product to provide at least equal energy and protein, compared to 2011 crop and pasture land areas. The x-axis is percentage of global land required. Note that replacing half of current animal nutrient consumption with beef would require more land than is physically possible, while soy bean curd (i.e. tofu) uses the least land of the products considered.


Alexander, P., Brown, C., Rounsevell, M., Finnigan, J., Arneth, A., 2016. Human appropriation of land for food: The role of diet. Global Environmental Change 41, 88–98.

This paper introduces the index Human Appropriation of Land for Food (HALF) and finds that if the world were to adopt the average Indian diet, the area of agricultural land needed would be approximately halved compared to today, while global consumption of the average USA diet would require nearly three times more land than currently used.

Helen Breewood's picture
Submitted by Helen Breewood on

Some interesting points have been brought up on Twitter.

Thanks to Richard Waite (@waiterich) for linking to the WRI report Shifting Diets for a Sustainable Food Future, which concludes that animal-based foods are, in general, higher in environmental impacts than plant-based foods - see the figure below.

And thanks to Michelle Cain (@civiltalker) for pointing out that the debate around economic effects of quinoa is far from settled: Your Quinoa Habit Really Did Help Peru's Poor. But There's Trouble Ahead​.

Miguel Astudillo's picture
Submitted by Miguel Astudillo (not verified) on

With the high tendency to motivated cognition it is problematic to focus on little details, instead of seeing the big picture. The trees will not let you see the forest. People will accept the evidence that does not challenge their position, which is for the most of wealthy contries, be a big meat eater.

I think what we need is good rules of thumb. And in general, plant-based products have a lower environmental footprint. That is a general trend obseved in many studies and a good rule of thumb. While for some particular individuals, this may not be the case (as the study of Rosy et al suggest), on average it is clear that plant-based diets have a lower impact.

Another issue, is if you want to understand better the nitty-gritty of sustainable diets. As a curiosity, I am missing is more studies of the enviromental effects of changing production systems. In the LCA jargon this is called "consequential" LCA. Many studies assess the environmental effects of changing diets using attributional databases, which technically wrong. In CLCA you need to look into how systems respond to changes, which could shed light on some of these questions. However, I do not expect CLCA would reverse the conclussions and the studies I've seen using it e.g Goldstein et al. ( point in the same direction. Reducing meat consumption is good for the environemnt. The lack of more sound studies and better data quality does not stop me for seing the general trend and reduce my meat consumption.

Martin Heller's picture
Submitted by Martin Heller (not verified) on

Good opening to an important discussion.  It is indeed true that there is a gap in data on newly introduced foods or those that have recently exploded in popularity.  And there are reasons to be skeptical: preliminary results from an LCA of soy protein isolate suggested impacts on par with meats, and although further scrutiny of this study identified problems, it definitely raises a flag for plant-based foods that require a high degree of processing.

I'd also like to point to this study which includes data on one of the plant-based "beef mimicker" burgers on the market.  Stay tuned for more like this!



Martin Heller

Annabel Mallett 's picture
Submitted by Annabel Mallett (not verified) on
Hello, i am studying for an EPQ and my choosen topic is "should veganism become mandatory in the uk in order to meet the uk demands for climate change". In order to address this topic i have broken it down into sub-questions. One being, " Is a vegan diet environmentally sustainable". Reading this i have been educated on many things i did not know previously and i have looked further into. However, i would like to know if there are a list of articles/books/research papers you would reccomend looking at to expland further into this topic. Many thanks, Annabel Mallett

Lana's picture
Submitted by Lana (not verified) on

You have cited a report by WWF and FCRN that states that replacing meat with meat substitutes would use up more land overseas. This simply cannot be correct due to the physics of animal feed production. Over 70% of soy goes towards animal feed globally, and meat and dairy is much more land and resource-intensive. I looked the original report by WWF and FCRN and it does not seem to include the land required for animal feed that feeds the livestock. Or do you have a different interpretation? Please can you clarify or correct the article. 

Helen Breewood's picture
Submitted by Helen Breewood on

Hi Lana, thanks for your comment. 

Table 39 of the report estimates that replacing UK-produced ruminant meat (beef and sheep) with Quorn, tofu and pulses (in proportions of 20%, 20% and 60%, respectively) would reduce arable land use in the UK by 11 kha, reduce "arable-forage" land use in the UK by 837 kha and increase overseas arable land use by 1,218 kha. As far as I can tell, Table 39 does in fact include land used for animal feed (the row "Land used for ruminant meat concentrates"). The report attributes the increase in overseas arable land use partly to the low yields per hectare of lentils and chickpeas, and notes that soy, lentils and chickpeas are not generally grown in the UK.

Please see also report co-author Donal Murphy-Bokern's comment above, which says "notes that a switch from (UK-produced) beef and milk to highly refined livestock product analogues such as tofu could actually increase the quantity of arable land needed to supply the UK.  This is simply because for a given amount of protein, the soy use in tofu is greater than the soy use for UK-produced beef or milk."

As far as I can tell, some of the high overseas land use estimated in the report is because some of the chosen substitutes, such as lentils and chickpeas, have fairly low yields per hectare. The results might have been different if the mix of substitute foods in the model had been chosen differently.

I have edited the article to point to the specific sources in the report, to make it clear that the estimate from Table 39 is for UK-produced ruminant meat only and to separately discuss the report's findings for pig and poultry meat substitutes. Please do let me know if you think the revised version is inaccurate.

Best wishes,


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