Should I Stop Eating Meat? Part IV
Scrutinise our previous assumptions and flesh out “it’s not the cow, it’s the how”
Part of a series. Part III here.
Assumption 1: It is safe to not eat meat
So under certain conditions we’ve established that reducing meat consumption (especially to zero) has a big impact on a personal scale on the embedded CO2e of what we eat. But is this safe? Can we really afford to not eat the stuff and is that healthy?
Yes. Eating a well-balanced plant-based diet is better than safe. It’s healthy. And maybe not just healthy, but very healthy. And you don’t need to take my advice on it (and you shouldn’t because I’m not a doctor or scientist), as many global health authorities provide the advice themselves. As listed here or here, there is huge scientific evidence for the health benefits of eating less meat, but also specifically no animal products at all.
But let’s back up slightly. I thought we eat meat (instead of plants) because it provides us the proteins we need (as well as iron) to grow and repair muscle? As is addressed comprehensively by James Wilks in The Game Changers documentary — and ruthlessly, to the point of it being humorous, defended here and here on Joe Rogan’s podcast — this is simply not true. The following is a quick overview, but more info is very concisely put here:
- There are 20 amino acids our body needs — 11 of which it can make (non-essential) and 9 of which food must provide (essential).
- Every single plant contains all of the essential amino acids, in varying proportions.
- The largest study comparing the nutrient intake of meat-eaters with plant-eaters showed that the average plant-eater not only gets enough protein, but 70% more than they need.
- The ‘type’ or ‘source’ of protein doesn’t matter, unless you are actually starving.
That last point is often the point that is raised. “Sure, you can get adequate protein but the package animal protein comes in is ‘better’”. That is true — but only if you are severely malnourished — which again James Wilks addresses aggressively here (he is an ex-UFC fighter) referencing the original science here.
So there are no concerns? Let’s try to answer that by assessing assumption 2.
Assumption 2: Meat can be reduced to calorie and protein intake
This assumption enabled us to make like-for-like comparisons between animal and non-animal based protein sources to keep things simple. But behind it is the implicit idea that in any meal where we previously had animal-based food, we substituted for plant-based and kept the meal otherwise identical. On a more holistic level the assumption manifests by saying that more veggie types eat similar cuisine to meat-eating types.
Is this true? Like everything else, it depends. Personally, I find that:
- without the knowledge of protein content of plant-based foods
- without the knowledge of how to make tasty vegan food
there can be a tendency for plant-based diets to not follow the assumption we have made — that when ‘transitioning’ the overall diet remains constant with a 1-for-1 swap of protein sources. Instead, there can be a tendency to increase carbohydrate intake instead of increasing bean/lentil/legume intake.
So what? Is this problematic?
Well, potentially. There has been a plethora of dietary advice dished out over the last 50 years with that advice potentially shaping why we’re now so protein obsessed — see here for a great overview. NHN also has a great section in her book on this and goes through the data on consumption vs health for the US. But to summarise it has essentially been:
- epidemiologist Ancel Keys in the 1950s (graced Time magazine front cover 1962) insists that saturated fat, particularly animal fat, is bad for us
- people eat less saturated fat
- people don’t get healthier
- the tide turns from fat to carbohydrates — specifically sugar and highly processed carbs
resulting in protein being the ‘last standing’ of the standard ‘macros’. All of this to say — it can potentially be problematic if you substitute meat in a diet for heavily refined carbs or sugar instead of more fruit and veg and legumes etc.
What about B12?
Yeah that’s an issue, but not because of what you think. If you are a vegetarian/vegan then you should be supplementing with B12 pills — that isn’t really a disputed point. However if you are not a vegetarian or vegan then you don’t have to because B12 is in animal meat. The reason why it is in animal meat though is probably not what you think. B12 comes from organisms in the soil and if animals chuck this soil in their mouth then they eat this B12 and then we eat them.
However, in industrial agriculture we chuck a load of pesticides on the ground which kills these organisms that make B12. So how does meat have B12 in it? We give B12 supplements to animals — industrial meat has B12 in it because we feed them supplements. So it’s up to you really — supplement yourself or supplement yourself via a supplemented animal. Not great really.
Assumption 3: Post-farm emissions are equally distributed
What was the purpose of this assumption? To make this clear before stripping it away, let’s take the classic argument about avocados:
“Maybe when looking globally avocados have a low CO2e footprint, but if you live in the UK then they can have a very high carbon footprint once you factor in flying them over. When you then compare this to local beef reared just down the road and from your local butcher the above conclusion doesn’t hold because the CO2e from processing and transporting is so great.”
So how does relaxing this assumption change the picture? It doesn’t. If anything, it maybe bolsters it.
Let’s start with one overly focused on topic: Food Miles.
The above argument rests on 2 central ideas, neither of which are true:
- Almost no one ever flies avocados. Ever. In fact we only fly 0.16% of food around the world with the remainder being trucked and shipped.
- Transport makes up a very very small part of the CO2e footprint of food. This lines up with the above charts with transport only accounting for 5%.
But let’s really hammer this home with a numerical example. Using the global average data above from PN2018:
- 1kg of beef averages 60kg CO2e
- 1kg of avocados averages 2.5kg CO2e
Shipping 1 tonne costs 23g of CO2e per kilometre. So if we assume we ship them the 9,000km from South America to London, then per kilo of avocados we end up with a ‘all-in’ CO2e number of:
(0.023 / 1,000) * 9,000 = 0.207kg + 2.5kg = 2.7kg CO2e per kg of avocados
Much smaller than the zero food miles 1kg of beef coming in at 60kg. As HR highlights here, from this paper in 2008, using the US as an example they found that going red meat and dairy free one day a week had the same effect as having a diet with zero food miles.
Yeah fine but post-farm is more than just transport — what about all the energy to process veggie alternatives?
Yes, it’s not. But the point remains. These processes, although more easily imagined to be energy/carbon intensive are only a small fraction of the carbon footprint of food. Again, we can use the data from PN2018 to illustrate this point. In fact as usual, HR has already done it for us.
The above shows how on a per food product basis the CO2e emissions break down. As is clear, the blue (processing), red (transport) and yellow (retail) sections are almost invisible on each bar. When compared to what it is we eat, how it is processed matters a lot less.
Assumption 4: We eat like ‘average global citizens’
And finally. The grand-daddy of the assumptions (but also the most vague). Stripping this assumption away is in effect asking the following question:
“Is there variation in the way food is grown and if so how does that variation impact (if at all) the CO2e profile of the food?”
And the answer to those questions is yes. Lots of it. It’s worth noting at this point that up until now we haven’t even bothered to ask what on earth is going on inside that black box of ‘agriculture’ that is spewing out all those GHG. We’ve just:
- treated it as a black box
- leveraged some numbers from experts in the field
- sense checked using some other numbers from other experts
- drawn some conclusions
So it’s going to be pretty difficult to understand where this variation comes from just yet. However let’s:
- first inspect the variation to see if it matters. Maybe there’s not enough to change our original conclusion
- build a farm as a thought experiment to try and understand what the black box of agriculture is doing to generate those pesky GHG
“It’s not the cow, it’s the how”
The above is the slogan of Nicolette Hahn Niman — vegetarian and ex-environmental lawyer — which she explains in her book ‘Defending Beef’. She keeps it very beef-specific in her incredibly well researched book, but the notion holds for all food production. Just like most other human activity, there are good ways to do things and bad ways to do things. Once again, PN2018 come to the rescue with the data we need. In order to compute their global averages they needed to look through all the individual data that underlie the respective distributions. We can look at that data to get a sense of the scale of the variation in CO2e numbers within a specific food product (beef, nuts, peas etc).
Woohoo!!! Distributions. So what does this show?
- again using protein as a benchmark, the above shows the distributions of kg CO2e produced when farming 100g worth of protein from each food
- instead of previously just representing with an ‘average’, we now see the full distribution with the previous average now marked as a white dot
- taking a numerical example, we can see that beef (amalgamated dairy and beef herd) has an average of 25kg CO2e per 100g protein, but has an incredibly wide distribution with the 10th and 90th percentiles respectively 9kg and 105kg
So does the variation in GHG emissions that these distributions represent change our initial assumption-constrained conclusion?
Put differently, can we construct a scenario where eating meat produces less GHG than eating plant-based equivalents? In short, no. It’s not necessarily obvious from the above so instead of the smooth distributions let’s make our own bar chart to show explicitly the 10th and 90th percentiles per food product along with the medians.
So the above stacked bar chart shows us the following:
- the 10th percentile (blue), median (green) and 90th percentiles (red) of kg CO2e per 100g of protein for each food from the PN2018 data
- the foods are then ranked where we rank according to either the best (10th) or worst (90th) depending on whether animal-based or not
The aim here is the following — if the numbers don’t even overlap, even when we take the best of the animal-based products and compare to the worst of the plant-based products, then our original conclusion still holds. So what do we see:
- the distributions generally don’t overlap: it is still almost always the case that no meat is better than low-carbon / ‘sustainable’ meat
- there are some instances where the ‘best’ fish, chicken and eggs outperform the ‘worst’ produced tofu i.e. their blue bars are smaller than the whole tofu bar
- nuts, lentils, chickpeas, kidney beans etc are always better in terms of CO2e than the best produced animal-based food
Quick Recap 2
Quite a data heavy bit so worth recapping what we’ve concluded thus far:
- even when we strip back the assumptions things are still looking good for the claim that eating a mostly/totally plant-based diet produces less GHG than a meat-inclusive diet
- even with the (sometimes huge) variation in GHG profiles of various foods, the above claim holds however it is potentially lessened to some degree
- not all meat is equal: there are ‘greener’ ways to produce 1kg of beef/meat that reduces the clear environmental credzzz that meat abstinence grants you
However we have the following issue: assuming we are not keen to give up our meat eating ways just yet but we do still want to minimise the impact of our diet on global warming, how can we identify these ‘low carbon’ meats?
And for that, it’s finally time to dive into the agriculture black box.
