Cost-effectiveness of Veganuary and School Plates

Vasco Grilo🔸

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We are grateful to Vasco for sharing this analysis with us prior to publication, for delaying in order to give us time to respond, and also for using his time to quantitatively explore the most impactful way to help animals.

While we appreciate Vasco’s intentions in producing this analysis, we believe there are reasons to be much more optimistic about Veganuary’s impact. We feel Vasco’s results reflect arbitrary assumptions based on his priors, rather than high-quality evidence about our campaign’s effectiveness.

Vasco’s calculations imply that Veganuary counterfactually reduced meat consumption by an extraordinarily small amount – the equivalent of just 1.3K metric tonnes. Around half of this is assumed to come from 25M direct pledge participants – who he assumes counterfactually reduce lifetime meat consumption by the equivalent of just 25g each (around 0.03% of annual meat consumption in the UK in 2021). The other half comes from all Veganuary’s other work, including our corporate engagement work, which we believe reaches many more people.

We regrettably think Vasco made very big adjustments that reflect his pessimism about our impact, but neither the magnitude of these judgements nor the degree of underlying uncertainty is communicated very clearly in his post. Crucially, Vasco arbitrarily assumed that Veganuary’s impact on pledge participants is 10x lower than the average effect size from the Green et al (2024) meta-analysis. Vasco’s justification of this is that our spend per pledge participant (c.$0.13) is probably a lot lower than the interventions in the Green et al (2024) meta-analysis.

We believe Veganuary might be a victim of its own success here. Being able to reach millions of people at low cost by creatively leveraging media and inspiring improved retail and food service offerings is a potential signal of effectiveness – but Vasco appears to have used this as a negative signal about our impact.

Vasco also assumed that the counterfactual impact of our non-pledge work is about the same as our work to inspire pledge participation. While this is hard to know for sure, we believe the counterfactual impact of our corporate engagement work to inspire more, better, and highly visible plant-based offerings in retailers and food service could be several times higher than arising from pledge participants.

We accept that properly measuring the counterfactual impact of interventions on animal product consumption is exceptionally hard, even more so with campaigns like Veganuary that gain national media coverage and influence product offerings at major retailers and food service outlets. We’d love to be able to allocate more resources towards measuring our impact. We aren’t yet in a position to provide quantitative estimates we feel we can stand by, but the following results make us optimistic our impact is likely to be much higher than what Vasco set out in his analysis:

Meat reduction data from Germany’s Statistical Office: The German Federal Statistical Office (Destatis) published that based on scanner data from German food retailers, 29.4% less meat was purchased in January 2024 than in December 2023. Compared to the 2023 annual average, meat sales in January 2024 were 12.5% lower than the previous 12 months. Compared to the 2022 annual average, meat sales in January 2023 were 14.3% lower than the previous 12 months.
New Research from the University of Exeter suggests that taking part in Veganuary leads to sustained reductions in meat consumption and can also produce fundamental shifts in people’s attitudes towards meat and their own self-identity as a meat-eater. Full study here.
Kantar data from the UK shows that, for 832K people who gave up animal products for the first time in January 2019, sustained reductions in animal product purchases over the following six months totalled 4,452,603 kg – equivalent to sparing 3.6 million animals by our calculations. While Veganuary cannot take all the counterfactual credit for these diet changes, it is striking how the estimated aggregate reduction in animal product consumption from pledge participants in just one country in 2019 is considerably higher than Vasco’s assumptions.
Participant surveys consistently show long-term dietary changes, with over 80% of surveyed email participants reducing animal product consumption by at least half, creating compounding benefits over time. We do of course recognise the selection bias in participant surveys, which is why we commissioned the Kantar study in 2019 and have switched to nationally representative surveys to better measure our reach.

While we are grateful for Vasco’s commitment to seeking the most cost-effective way to help animals, we think he has made arbitrary judgements that make Veganuary look considerably less cost-effective than we believe it is and has not clearly explained these judgements in a way is helpful for readers.

While we accept it is exceptionally difficult to measure the impact of interventions like Veganuary, which use the diet change element of its work to drive progress through corporate engagement, we welcome ideas from readers on ideas of how we might be able to do this (and resources to help run such studies). We also welcome serious attempts to measure our effectiveness that legibly explain key cruxes/judgements/uncertainties, and credible suggestions on how we can improve our effectiveness (acknowledging we operate under constraints given our name, branding, and supporter base).

Toni Vernelli, International Head of Communications, Veganuary

Vasco Grilo🔸

1y*

Thanks, Toni!

Vasco’s calculations imply that Veganuary counterfactually reduced meat consumption by an extraordinarily small amount – the equivalent of just 1.3K metric tonnes. Around half of this is assumed to come from 25M direct pledge participants – who he assumes counterfactually reduce lifetime meat consumption by the equivalent of just 25g each (around 0.03% of annual meat consumption in the UK in 2021). The other half comes from all Veganuary’s other work, including our corporate engagement work, which we believe reaches many more people.

I agree these numbers follow from my assumptions, but they do not seem super low to me. I do not have strong expectations about the mean reduction in meat consumption in kg among the people who reported participating in Veganuary. Note "My effect size refers to people who reported participating in Veganuary. The number of people who actually participated may be significantly smaller. Veganuary concluded 25 M participated multiplying small fractions of participants in the surveyed countries by their populations. However, such fractions may be significantly explained by a few people mistakenly reporting their participation due to lack of attention or social desirability bias".

We regrettably think Vasco made very big adjustments that reflect his pessimism about our impact, but neither the magnitude of these judgements nor the degree of underlying uncertainty is communicated very clearly in his post. For example, Vasco arbitrarily assumed that Veganuary’s impact on pledge participants is 10x lower than the average effect size from the Green et al (2024) meta-analysis. Vasco’s justification of this is that our spend per pledge participant (c.$0.13) is probably a lot lower than the interventions in the Green et al (2024) meta-analysis.

Nitpick. Using "For example" may suggest you think there are many other important assumptions I made which you think are "arbitrary". However, I guess my assumptions about the effect per person who reported participating in the pledge, and the effect on people who did not participate in the pledge, which you mentioned in your comment, are the most important, and the ones you disagree with the most. Are there others? If not, I think "Crucially" or "In particular" would communicate your views more faithfully than "For example".

We believe Veganuary might be a victim of its own success here. Being able to reach millions of people at low cost by creatively leveraging media and inspiring improved retail and food service offerings is a potential signal of effectiveness – but Vasco appears to have used this as a negative signal about our impact.

My prior is that the effect per person decreases with the number of people affected. So more people being affected updates me towards a smaller effect per person. However, it does not necessarily update me towards a lower impact.

Meat reduction data from Germany’s Statistical Office: The German Federal Statistical Office (Destatis) published that based on scanner data from German food retailers, 29.4% less meat was purchased in January 2024 than in December 2023. Compared to the 2023 annual average, meat sales in January 2024 were 12.5% lower than the previous 12 months. Compared to the 2022 annual average, meat sales in January 2023 were 14.3% lower than the previous 12 months.

I do not know whether that was caused by Veganuary. The meat consumption per capita excluding fish and seafood in Germany peaked in 1987, well before Veganuary started in the UK in 2014, and has trended downwards unevenly since then.

From the point of view of animal welfare, it is much more important to look into the number of poultry birds and aquatic animals per capita. In Germany, the number of poultry birds per capita increased from 1.67 (= 135*10^6/(81.0*10^6)) in 2014 (when Veganuary started in the UK) to 2.07 (= 173*10^6/(83.6*10^6)) in 2020 (the last year for which there is data about the number of poultry birds on Our World in Data (OWID)), i.e. 24.0 % (= 2.07/1.67 - 1). The vast majority of this increased happened from 2014 to 2016.

New Research from the University of Exeter suggests that taking part in Veganuary leads to sustained reductions in meat consumption and can also produce fundamental shifts in people’s attitudes towards meat and their own self-identity as a meat-eater. Full study here.

The study looked into just 40 highly selected people^[1], and there was no control group or measures to mitigate social desirability bias.

Kantar data from the UK shows that, for 832K people who gave up animal products for the first time in January 2019, sustained reductions in animal product purchases over the following six months totalled 4,452,603 kg – equivalent to sparing 3.6 million animals by our calculations. While Veganuary cannot take all the counterfactual credit for these diet changes, it is striking how the estimated aggregate reduction in animal product consumption from pledge participants in just one country in 2019 is considerably higher than Vasco’s assumptions.

Could you share a link? I would not be surprised if only 1 % of that meat reduction had been caused by Veganuary, in which case there would be little tension with my results. I would also like to know about the changes in the consumption of specific types of animal-based foods.

I worry about replacements of red meat with white meat, eggs, and farmed aquatic animals, which respect a greater suffering per kg. Veganuary started in the United Kingdom in 2014, and the production of broilers per person in there in January increased 4.27 times as fast from 2014 to 2024 as from 1994 to 2013. Data about consumption (production plus net imports) would be more informative, and the production of broilers per person could have increased faster without Veganuary, but the correlation is still concerning.

While we are grateful for Vasco’s commitment to seeking the most cost-effective way to help animals, we think he has made arbitrary judgements that make Veganuary look considerably less cost-effective than we believe it is and has not clearly explained these judgements in a way is helpful for readers.

I estimated Veganuary in 2024 was 1.20 % as cost-effective as cage-free campaigns, and that these are 0.718 % as cost-effective as SWP. So I think more optimistic assumptions about Veganuary would still leave it much less cost-effective that SWP.

^{^}
The pre-screen survey was completed by 1,125 people on Prolific. Of those, 60 were eligible participants (who were either omnivores or flexitarians and intended to take part in Veganuary or a different meat-free January challenge) and were invited to the baseline survey. 48 participants completed this survey without failing more than one of three attention check questions. All of these were invited to the follow-up survey in February which was completed without more than one failed attention check by all of the 40 people who participated in it.

Felix_Werdermann 🔸

1y*

My understanding of the argument regarding “Meat reduction data from Germany's Statistical Office” is that significantly less meat is consumed in January than in the other months (I don't understand the argument in the sense that Veganuary has contributed to the downward trend over the years). Perhaps it would be better to compare the value for January 2023 with the monthly average for 2023 than with the monthly average for 2022, because this would rule out the possibility that the comparatively low consumption is due to the downward trend over the years. However, since the annual decline is less than 12.5% or 14.3%, consumption in January is also lower than the average month of the corresponding year.
The fact that the consumption of poultry meat in Germany has risen in recent years is very regrettable, but I don't believe that this is due to Veganuary. However, the German Statistical Office should also have figures for different animal species, so you should be able to see whether the consumption of poultry meat is higher, lower or similar in January compared to other months.
I don't think comparing January with December is very helpful because December is an atypical month due to Christmas.

PreciousPig

1y*

Dear Vasco,
Dear Team of Veganuary,

I want to thank you both for your input/contributions here as I think it is incredibly important to properly verify the actual effectiveness of any possible intervention to help animals. I have followed Veganuary’s success for many year and am a long-time donor, and have previously tried to estimate your actual impact, for example here.

Reasons I am positive about the impact of Veganuary:

I think there are some incredibly promising metrics about Veganuary’s success, for examnple this 2019 survey on why people go Vegan in which 12800 people participated, out of them 369 (a little under 3%) said that Veganuary was the first thing that seriously made them consider going Vegan. If we assume this metric is accurate and still holds true today, and that roughly 1% of the people in Europe and North America are Vegan (or very roughly 10 milllion people out of 1 billion people), as many as 280 000 people might be Vegan today because of Veganuary. If we further assume each Vegan person saves on average one animal’s live a day, that would be 100 000 000 (100 million) animals spared each year due to Veganuary.
(I know I am making a lot of big assumptions here and some of those number are almost certainly too optimistic, for example an online poll like the one I linked will almost certainly overrepresent a primarily online campaign like Veganaury. I also don’t know how to convert that number to the metric of SAD’s used here)

Reasons I think Veganuary might be less impactful than it used to be:

I also think there are some worrying signs about the success of Veganuary, specifically in the last three years.

1) My biggest reason for this is that the actual search interest in Veganuary is decreasing since 2022, google trends show that there there was only 57% as much search interest in Veganaury in January 2025 as there was in 2020 and 2022 (The two years with the highest search interest):

2) My second reason is that the amount of people who sign up to the core of your Veganaury Campaing – the 31 daily Emails – seems to be decreasing:

2022 Here is Veganaury’s 2022 report: https://veganuary.com/wp-content/uploads/2022/03/Veganuary-2022-End-Of-Campaign-Report.pdf where you reported 629 000 people signing up / 19,6 million emails sent (31,16 Emails per signup, so checks out pretty closely with 31 days in January)

2024 Heres the 2024 report:
https://veganuary.com/wp-content/uploads/2024/03/Campaign-Report-2024-UK.pdf in which you no longer posted a direct amount of people who had signed up by Email, but you sent 17,5 million Emails. Assuming again 31,16 Emails per participant, that is around 560000 signups, a clear decrease from the 700k you reported in 2023. (https://veganuary.com/wp-content/uploads/2023/12/Veganuary-2023-EoC-Report-UK.pdf) – If I am correct here, last year was the first time your campaign significantly decreased compared to the year before in the amount of Email signups. I hope you will once again share the number of Email signups for Veganaury 2025 so we have a better comparison.

I know you say your campaign has spread to other channels instead of just Email like YouTube, podcasts, etc. - But every single Veganuary website (All individual country campaigns) I visit still asks me only to sign up by Email, so I strongly believe that this is still the core of your campaign and the best indicator of your campaigns actual success. I also believe if your campaign in 2025 was much bigger than 2022 due to people using many other channels compared to just Email, we would see search interest increasing on Google trends instead of decreasing.

Suggestions how I think you can better verify your actual impact:

Besides continuing to share the number of Email signups, here are some ways how I think you could increase / confirm the accuracy of the YouGov survey:

1 – Run a similar YouGov Survey about a completely made up campaign similar to Veganaury and see if results are different. For example ask participants if they have participated in „Plantober“ – A challenge for people to eat plant based for the month of October – which does of course not exist, so we would expect that 0% respond that they participated in such a poll if it is accurate. If the number is above 0 but below the YouGov numbers for Veganuary, that might be a good indicator to how much the YouGov survey overestimates participation. If the results are similar to the YouGov poll about Veganaury, we should probably not trust these polls at all anymore.

2 – Make the poll have 2 parts and do not direcly bring up Veganuary in it. For example:
Question 1 – Have you decreased your consumption of any specific type of product in the month of January?
Question 2 – Asked to anyone who answers „animal products“ / „meat“ or similar in question 1 – What was your primary motivation to do so? And then report the amount of people who say they decreased animal product consumption because of Veganuary.
This would not only reduce social desirability as a factor since people would have to say what they reduced themselves, but also show what percentage of people who say they did decrease their animal product consumption did so because of Veganuary.

Finally, I want to thank you for the incredible work you are doing and your openness to respond to criticism! I might sound overly negative in my response here, but I am genuinely a great fan and longtime supporter of Veganuary and I do think that Vasco is definitely underestimating your impact.

Edit: Spelling and small changes for clarity.

Vasco Grilo🔸

1y*

Thanks for the comment, @PreciousPig! I strongly upvoted it. I am tagging you because my initial comment only included the 2 sentences before this one.

Dear Team of Veganuary,

I am tagging @Toni Vernelli such that Veganuary's team knows about your comment (only the author of the post is notified of new comments by default).

I think there are some incredibly promising metrics about Veganuary’s success, for examnple this 2019 survey on why people go Vegan in which 12800 people participated, out of them 369 (a little under 3%) said that Veganuary was the first thing that seriously made them consider going Vegan.

"369 people [2.88 % (= 369/12,814) of the vegans surveyed] succesfully took part in Veganuary [being vegan for 1 month]". It does not follow that Veganuary caused these people to become vegan. Moreover, even if everyone who successfully took part in Veganuary became permanently vegan, they could have become so a little later anyway without Veganuary.

Nitpick. I wonder whether you are using "for example" to present your strongest argument for Veganuary being cost-effective. If yes, I think "crucially" would convey your views more faithfully than "for example".

If we assume this metric is accurate and still holds true today, and that roughly 1% of the people in Europe and North America are Vegan (or very roughly 10 milllion people out of 1 billion people), as many as 280 000 people might be Vegan today because of Veganuary. If we further assume each Vegan person saves on average one animal’s live a day, that would be 100 000 000 (100 million) animals spared each year due to Veganuary.

The survey you linked to looked into 0.128 % (= 12.8*10^3/(10*10^6)) as many vegans as those you estimated exist in Europe and North America. So here is room for huge selection bias. The number of people successfully participating in Veganuary as a fraction of the number of vegans could be as low as 3.69*10^-5 (= 0.00128*0.0288) even if the data from the survey was 100 % reliable (athough highly selected).

Besides continuing to share the number of Email signups, here are some ways how I think you could increase / confirm the accuracy of the YouGov survey:

I would ask questions like these to random (representative) samples of the general population in the target countries:

How much more or less poultry meat would you have consumed in January without Veganuary?
How much more or less poultry meat would you have consumed in January without Plantuary?

The possible answers could be like these:

I consumed 100 % less poultry meat (I did not consume poultry meat).
I consumed 80 % less poultry meat.
...
I consumed roughly the same poultry meat.
I consumed 20 % more poultry meat.
...
I consumed 100 % more poultry meat (I doubled my consumption of poultry meat).
I more than doubled my consumption of poultry meat.

I would have similar questions for eggs, fish, and seafood besides fish. My suggested questions:

Focus on the animal-based products linked to the vast majority of animal suffering. They do not ask about whether people participated in Veganuary because what ultimately matters is whether they reduced their consumption of animal-based foods.
Include control questions about Plantuary, which sounds similar to Veganuary, but does not exist. The effect of Veganuary should be measured relative to that of the control campaign. I expect people will report reducing their consumption of animal-based products because of Plantuary, in the same way that 4 % of Americans report believing lizardmen are running the Earth.
Have continuous answers which offer more information. I am wary of questions which can only be answered as yes or no. Social desirability bias will prompt people to report decreasing the consumption of animal-based foods even if the decrease was negligible.

I think it would be great if Veganuary partnered with Faunalytics or the Humane and Sustainable Food Lab to run a rigorous survey.

Joseph Richardson

1y*

I'd add that your Veganuary participation numbers are likely way too generous. They come from a poll of the general public on participation and then scaling those numbers up to a broader population. However, opinion polling of this type famously overestimates the share of the population with rare characteristics due to mistakes, trolling, or in this case potentially social desirability bias.

Indeed, I have the impression that surveys estimating the share of vegans in the US population often getting about 5%, which is around the lizardman constant. Objective purchase data suggests that the number is more like 1%.

Vasco Grilo🔸

Nice to hear from you, Joseph! Great point. I have changed "participated in Veganuary" to "reported participating in Veganuary", which was what I meant. I have added the following to:

The summary and discussion. "I would also add a question to the survey used to determine the number of people who participated in Veganuary which would check whether the respondents are replying in good faith. This is important because only a small fraction of the population participates in Veganuary, such that small errors matter. 4 % of Americans believe (actually, report believing) lizardmen are running the Earth".
The section about the cost-effectiveness of Veganuary. "My effect size refers to people who reported participating in Veganuary. The number of people who actually participated may be significantly smaller. Veganuary concluded 25 M participated multiplying small fractions of participants in the surveyed countries by their populations. However, such fractions may be significantly explained by a few people mistakenly reporting their participation due to lack of attention or social desirability bias".

Toni Vernelli

I have tried to post Veganuary's reply twice now and the spam-blocker immediately deletes it. I do not have the intercom icon so I don't know how to contact the admin to get this resolved. I hope they will see this message and post my comment.

Dane Valerie

Apologies, Toni! We’ve restored your comment—it should be visible now.

Sjlver

It's great to try and analyze the cost-effectiveness of Veganuary. I'm thankful for this post and also for the responses by @Toni Vernelli and others.

While I appreciate the effort, I find it hard to agree with Vasco's conclusions. There are many discounts in the analysis that feel pretty arbitrary to me. Toni has answered to this much better than I could. I'd just like to share a few personal impressions. These are of course biased, but might explain why I'm suspicious about the many downward adjustments (and lack of upward adjustments) in Vasco's analysis:

Veganuary is quite prominent where I live. There are numerous new products in supermarkets. I've seen many ads for vegan products in January, not directly by Veganuary but by franchises like Burger King.
During Veganuary 2020, my wife and I made the decision to become vegan. We had been vegetarians before, and found out during Veganuary that a fully vegan lifestyle was easier than expected. Since then, one of our flatmates transitioned from omnivore to vegan. Another flatmate stayed omnivore but ate mostly vegan during the year that she lived with us. This is an extreme example, but it shows that the 31 emails can affect more than just one person, and for a duration longer than 6 months.

Overall, there seems to be a clear trend in Germany toward more vegan products. Oat milk shelves are larger than cow milk shelves in many retailers nowadays; there are many meat alternatives; vegan products are becoming popular also in other areas such as chocolate and baked goods. It's difficult to isolate the effect that Veganuary has played in all this... but I'd be surprised if it was as small as Vasco estimates.

Vasco Grilo🔸

Thanks for the comment, Sjlver!

many downward adjustments (and lack of upward adjustments)

My cost-effectiveness estimate is supposed to be unbiased in the sense of not being too low or high in expectation.

During Veganuary 2020, my wife and I made the decision to become vegan. We had been vegetarians before, and found out during Veganuary that a fully vegan lifestyle was easier than expected. Since then, one of our flatmates transitioned from omnivore to vegan. Another flatmate stayed omnivore but ate mostly vegan during the year that she lived with us. This is an extreme example, but it shows that the 31 emails can affect more than just one person, and for a duration longer than 6 months.

To be clear, I think one single email or video can turn someone from omnivoure to vegan. However, I believe that is super far from the expected effect.

Overall, there seems to be a clear trend in Germany toward more vegan products.

The supply per capita of poultry meat in Germany has not had a clear downwards trend, although it does seem like it has already peaked.

Likewise for the supply per capita of fish and other seafood in Germany.

However, this is very weak evidence of the impact of Veganuary. There are many factors which affect meat consumption in Germany besides Veganuary, and that may well be the country which Veganuary targets with the most positive trends. In the UK, the consumption per capita of poultry meat has been increasing, although that on fish and other seafood has recently been decreasing.

Oat milk shelves are larger than cow milk shelves in many retailers nowadays

Nitpick. Dairy accounts for a very small fraction of animal suffering. I think decreases in its consumption only matter to the extent they predict decreases in the consumption of eggs, poultry birds, fish, or other seafood.

Sjlver

Thanks for the response!

I understand that you are worried about chicken and fish consumption. I have no knowledge about why these charts are the way they are, or why people in the UK consume twice as much chicken as those in Germany. It's also difficult to guess the impact of Veganuary in these trends. Insofar, I find the charts a bit distracting.

What I intended to say with my comment is that Veganuary has clearly visible impacts around me: when I go shopping, when I see ads, when I eat out. This seems to correlate with a general trend of seeing more vegan products, brands, and menu choices. Maybe the general trend that I identified is similarly distracting as your chicken and fish charts... yet it does seem to be something that Veganuary directly works on and influences.

I suspect that you brought up the chicken and fish charts because you worry about shifts in consumption from larger animals to higher numbers of small animals. This is a real possibility, but I would be wary of accusing Veganuary to cause such a shift, without good evidence. I grant that Veganuary tries to appeal to a broad range of people with various reasons for reducing meat consumption, including climate reasons which might cause a shift away from ruminants. But I recall there was a lot of Veganuary content around animal welfare. Personally, Veganuary shifted my views to care more about animals.

Animal welfare seems to be the main participant motivation. Here's a figure from the 2023 survey report:

Taking a step back, it's a little sad that this article feels so hostile towards Veganuary, and shows Veganuary in a bad light primarily because of discounts and back-of-the-envelope numbers that seem quite arbitrary. I see a lot less competition than you do between Veganuary and work on shrimp welfare or cage-free campaigns. On the contrary, people who have participated in Veganuary are likely more receptive for that type of work, and this is a benefit that we won't find in CEAs ;-)

Vasco Grilo🔸

Thanks for the comment, Sjlver!

many downward adjustments (and lack of upward adjustments)

My cost-effectiveness estimate is supposed to be unbiased in the sense of not being too low or high in expectation.

During Veganuary 2020, my wife and I made the decision to become vegan. We had been vegetarians before, and found out during Veganuary that a fully vegan lifestyle was easier than expected. Since then, one of our flatmates transitioned from omnivore to vegan. Another flatmate stayed omnivore but ate mostly vegan during the year that she lived with us. This is an extreme example, but it shows that the 31 emails can affect more than just one person, and for a duration longer than 6 months.

To be clear, I think one single email or video can turn someone from omnivoure to vegan. However, I believe that is super far from the expected effect.

Overall, there seems to be a clear trend in Germany toward more vegan products.

The supply per capita of poultry meat in Germany has not had a clear downwards trend, although it does seem like it has already peaked.

Likewise for the supply per capita of fish and other seafood in Germany.

Oat milk shelves are larger than cow milk shelves in many retailers nowadays

Comments

Vasco Grilo🔸

1y*

Thanks, Toni!

Vasco’s calculations imply that Veganuary counterfactually reduced meat consumption by an extraordinarily small amount – the equivalent of just 1.3K metric tonnes. Around half of this is assumed to come from 25M direct pledge participants – who he assumes counterfactually reduce lifetime meat consumption by the equivalent of just 25g each (around 0.03% of annual meat consumption in the UK in 2021). The other half comes from all Veganuary’s other work, including our corporate engagement work, which we believe reaches many more people.

We regrettably think Vasco made very big adjustments that reflect his pessimism about our impact, but neither the magnitude of these judgements nor the degree of underlying uncertainty is communicated very clearly in his post. For example, Vasco arbitrarily assumed that Veganuary’s impact on pledge participants is 10x lower than the average effect size from the Green et al (2024) meta-analysis. Vasco’s justification of this is that our spend per pledge participant (c.$0.13) is probably a lot lower than the interventions in the Green et al (2024) meta-analysis.

We believe Veganuary might be a victim of its own success here. Being able to reach millions of people at low cost by creatively leveraging media and inspiring improved retail and food service offerings is a potential signal of effectiveness – but Vasco appears to have used this as a negative signal about our impact.

Meat reduction data from Germany’s Statistical Office: The German Federal Statistical Office (Destatis) published that based on scanner data from German food retailers, 29.4% less meat was purchased in January 2024 than in December 2023. Compared to the 2023 annual average, meat sales in January 2024 were 12.5% lower than the previous 12 months. Compared to the 2022 annual average, meat sales in January 2023 were 14.3% lower than the previous 12 months.

New Research from the University of Exeter suggests that taking part in Veganuary leads to sustained reductions in meat consumption and can also produce fundamental shifts in people’s attitudes towards meat and their own self-identity as a meat-eater. Full study here.

The study looked into just 40 highly selected people^[1], and there was no control group or measures to mitigate social desirability bias.

Kantar data from the UK shows that, for 832K people who gave up animal products for the first time in January 2019, sustained reductions in animal product purchases over the following six months totalled 4,452,603 kg – equivalent to sparing 3.6 million animals by our calculations. While Veganuary cannot take all the counterfactual credit for these diet changes, it is striking how the estimated aggregate reduction in animal product consumption from pledge participants in just one country in 2019 is considerably higher than Vasco’s assumptions.

I worry about replacements of red meat with white meat, eggs, and farmed aquatic animals, which respect a greater suffering per kg. Veganuary started in the United Kingdom in 2014, and the production of broilers per person in there in January increased 4.27 times as fast from 2014 to 2024 as from 1994 to 2013. Data about consumption (production plus net imports) would be more informative, and the production of broilers per person could have increased faster without Veganuary, but the correlation is still concerning.

While we are grateful for Vasco’s commitment to seeking the most cost-effective way to help animals, we think he has made arbitrary judgements that make Veganuary look considerably less cost-effective than we believe it is and has not clearly explained these judgements in a way is helpful for readers.

^{^}
The pre-screen survey was completed by 1,125 people on Prolific. Of those, 60 were eligible participants (who were either omnivores or flexitarians and intended to take part in Veganuary or a different meat-free January challenge) and were invited to the baseline survey. 48 participants completed this survey without failing more than one of three attention check questions. All of these were invited to the follow-up survey in February which was completed without more than one failed attention check by all of the 40 people who participated in it.

^{^}

In this case, “variance of the monthly consumption of meat” = (“variance of the daily consumption of processed meat” + “variance of the daily consumption of non-processed red meat” + “variance of the daily consumption of non-processed poultry”)*“number of days per month”.

^{^}

“In this population, mean (standard deviation) consumption was 35.0 (34.0) g/day for processed meat, 31.9 (28.2) g/day for red meat, and 33.8 (28.3) g/day for poultry. The correlations between the intake of the different meat categories (in g/day) were: r = 0.05, p < 0.01 (between processed meat and red meat), r = -0.02, p = 0.21 (between processed meat and poultry), and r = 0.11, p < 0.01 (between red meat and poultry).”

^{^}

“Mean monthly consumption of meat” = (“mean daily consumption of processed meat” + “mean daily consumption of non-processed red meat” + “mean daily consumption of non-processed poultry”)*“number of days per month”.

^{^}

Thanks to ChatGPT for suggesting arguably catchy names.

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I listed the names alphabetically.

Cost-effectiveness of Veganuary and School Plates

Summary

Cost-effectiveness

Veganuary

School Plates

Cage-free campaigns

Comparisons

Discussion

Veganuary

School Plates

Comparisons

Acknowledgements