I read Lierre Keith's book Vegetarian Myth about a year ago (great book!). For those who haven't read it, she responds to the argument that real food (i.e., not vegetarian) for all is unsustainable by saying maybe yes, but growing grain is also unsustainable because it's destroying top soil/farmland. I think it's a reasonable response. But, I'm not sure it's enough to convince the masses because we have been growing grains for a while, and they don't "see" it destroying top soil/farmland.
Mark Sisson wrote a good series on this where he did discuss some of the challenges with primal for all, as well as some good strategies for how it could be made more do-able, but he doesn't seem to give a definitive yes or no on if it's possible:
Robb Wolf also wrote a good article on the topic, but also doesn't seem to give a definitive yes or no:
And of course, there is Melissa's excellent PH post which makes good points on why paleo-based diet is more sustainable than SAD diet, but doesn't focus on if it's sustainable for entire world to be paleo/primal:
Anyway, on to my question. After reading Lierre's book, I really wanted to know what kind of population could the Earth support if everyone ate paleo/primal. I sent her this e-mail:
I really like your book. I have one question. In the middle of page 101, you say a 10 acre farm of perennial polyculture in mid-Atlantic can produce 6.8M calories (enough for 9 people) which works out to 1.1 acres/person. On page 124, you say there are 28.2B acres of bioproductive land (after removing oceans, deserts, ice caps, built-up land) or 4.7 acres per person. You say 25-75% needs to be reserved, so that would leave 1.2-3.5 acres per person for food production. It seems then that there is some possibility for the whole world to live off of perennial polyculture food production? If yes, then sustainable living is possible without reducing the world population? I understand that other climates might not support as much production as mid-Atlantic, but this also ignores any fishing which might help offset that.
Am I misunderstanding something? Does this mean I can cancel my vasectomy? :)
I never got a response, but am thinking maybe you can all can provide some insight. Please hack my weak logic and faulty assumptions. Some weaknesses I can think of:
- Some bioproductive land may not be as productive as mid-Atlantic
- Joel Salatin at Polyface Farms (on which Lierre's 6.8M calories/10 acres estimate is based) does supplement his chickens with grain he purchases
- Bioproductive land estimate includes rain forest, etc? So all that land would have to be clear cut? Maybe not a good idea. Or perhaps used in a less productive way to produce food?
- Maybe some of Leirre's numbers are incorrect?
What other problems do you see? How much do these affect the answer? Is it actually possible to feed everyone on a paleo/primal diet? If no, how many people could be supported?
UPDATE: Thanks everyone. Very useful responses. I found a few page paper written by Joel Salatin on the topic which is quite interesting:
His view is that it is sustainable to feed everyone real food, but his logic is more just saying that growing real food using proper practices is more efficient that growing what we grow today. And that a lot of the assumptions around real food/proper practices being unsustainable are based on old practices and old technology. It's an interesting paper, though it doesn't try to do any sort of calculation like I have above, so maybe isn't real proof.
My big point with this question is that I don't think we should continue to assume/concede that paleo for all is unsustainable. Make the "other side" prove it and then we can poke holes in their calculations. Or, can we do our own calculations to prove that it is potentially sustainable? I think so...
UPDATE: I have since posed a similar question with a simpler calculation here: