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What's the break down of average human caloric intake from animals vs. plants? Is calories from animals close to the same fraction (77%)? If so, then changing f

What's the break down of average human caloric intake from animals vs. plants? Is calories from animals close to the same fraction (77%)? If so, then changing from animal to plant diet wouldn't reduce the land requirements much.

rsynnott 6y ago
Even if it was, removing animals from the equation should reduce land use a lot, as an animal is, in this context, a machine for turning calories into fewer calories (of course looking at just calories is a bit of a simplification).
- hinkley 6y ago
  Unfortunately a lot of prairie and forest-edge plants (where most of our calories come from) are adapted to herbivores. You can't maintain a healthy ecosystem without them, and we've been resorting to petrochemical fertilizers and pesticides to try to compensate. If a fruit tree survives browsing by deer, for instance, it is much better protected from some very common diseases that overwinter on the ground under the tree. Because of this, Mark Shepard and a few other people (especially that guy who wants to use cows in Africa to control erosion) think we should have about a quarter as many animals on our farms, but that every farm should have them. The animals are there to work first, produce calories second. It's not a yes/no question, it's a matter of degrees. We should be eating less meat, and sourcing it from more places, and less worried about Grade-A cuts (fewer steaks, more stews)
hinkley 6y ago
I don't have those answers, but it's been widely reported that the carbon footprint of a calorie of chicken is about one quarter the footprint of a calorie of beef. Just switching animal proteins is a big change. And chickens are omnivores. Feeding them invertebrates instead of feed corn would be a more natural diet for them, and you can use food no longer fit for humans as the feedstock for those invertebrates without switching humans to cricket flour. I know of a guy who uses cows, pigs, and chickens to control pathogen load on his farm. The lifecycle of flies on cow manure are very predictable, and with some discipline you can use it as feedstock for the chickens. We know how to do this outside, I doubt they know how to do it in a feed lot (although, making it work in a feedlot would necessarily result in better sanitation for the cows/pigs, since you'd have to isolate their waste chronologically). Part of pathogen control is sending your inputs through as many diverse digestive tracts as you can. Or using a ton of chemicals. Mammal->insect->chicken->human is pretty good for eliminating parasites, though maybe not salmonella. [ETA] Most of what I said about chicken feed is also true of pigs, although their footprint is somewhere between the two extremes.
- Robotbeat 6y ago
  But where do the invertibrates get THEIR food from? Feed corn is super cheap per calorie (people sometimes burn feedcorn in stoves for heat), so it’s probably what you’d feed the invertebrates. Edit: Yup, insect farms typically use grains as the feed. Grains which you could eat directly (after baking or cooking, of course) which would be more calorically efficient. https://www.theatlantic.com/health/archive/2015/09/americas-cricket-farmers/406843/ https://www.theatlantic.com/health/archive/2015/09/americas-...
  - hinkley 6y ago
    I can't deny that feed corn has good shelf life (they store it outside under a tarp when the silos are full). But there are other food streams that don't necessarily pass inspection, especially for perishable foods. I know from a couple days at a food bank that cows can eat pretty bad apples, but there are badness levels that would be much safer for grubs or larvae to eat. Feed corn takes a lot of water though, and I don't know how much longer we'll have that.
    - Robotbeat 6y ago
      Typically insects used for human consumption are fed grains (such as feed corn), but with a conversion efficiency making the problem worse. True that smaller operations, family farms, and homesteads could take advantage of waste streams like that, but that is kind of a logistical nightmare for feeding of large urban/suburban populations.
      - hinkley 6y ago
        We need to stop thinking we are going to fix our many many problems that we have created through a multitude of individual decisions by finding One Weird Trick. It's magic thinking, and we're supposed to be grown-ups. Whatever that means. Solutions don't have to scale infinitely. They just have to scale.
  - boo_boo 6y ago
    > Yup, insect farms typically use grains as the feed. Grains which you could eat directly (after baking or cooking, of course) which would be more calorically efficient. Black soldier fly larvae can be fed almost any organic matter, including waste. The use of grain as feed for insect farms (which can largely be attributed to grain subsidies) doesn't imply it's the end-all energy input.
Robotbeat 6y ago
Less than 28% of the American diet is from animals (meat, eggs, and dairy) by calorie. https://grist.org/industrial-agriculture/2011-04-05-american-diet-one-chart-lots-of-fats-sugars/ https://grist.org/industrial-agriculture/2011-04-05-american...
shafyy 6y ago
We get 18% of calories and 37% of protein from animal foods (same source as above).

rsynnott 6y ago

Even if it was, removing animals from the equation should reduce land use a lot, as an animal is, in this context, a machine for turning calories into fewer calories (of course looking at just calories is a bit of a simplification).

hinkley 6y ago
Unfortunately a lot of prairie and forest-edge plants (where most of our calories come from) are adapted to herbivores. You can't maintain a healthy ecosystem without them, and we've been resorting to petrochemical fertilizers and pesticides to try to compensate. If a fruit tree survives browsing by deer, for instance, it is much better protected from some very common diseases that overwinter on the ground under the tree. Because of this, Mark Shepard and a few other people (especially that guy who wants to use cows in Africa to control erosion) think we should have about a quarter as many animals on our farms, but that every farm should have them. The animals are there to work first, produce calories second. It's not a yes/no question, it's a matter of degrees. We should be eating less meat, and sourcing it from more places, and less worried about Grade-A cuts (fewer steaks, more stews)

hinkley 6y ago

I don't have those answers, but it's been widely reported that the carbon footprint of a calorie of chicken is about one quarter the footprint of a calorie of beef. Just switching animal proteins is a big change. And chickens are omnivores. Feeding them invertebrates instead of feed corn would be a more natural diet for them, and you can use food no longer fit for humans as the feedstock for those invertebrates without switching humans to cricket flour. I know of a guy who uses cows, pigs, and chickens to control pathogen load on his farm. The lifecycle of flies on cow manure are very predictable, and with some discipline you can use it as feedstock for the chickens. We know how to do this outside, I doubt they know how to do it in a feed lot (although, making it work in a feedlot would necessarily result in better sanitation for the cows/pigs, since you'd have to isolate their waste chronologically). Part of pathogen control is sending your inputs through as many diverse digestive tracts as you can. Or using a ton of chemicals. Mammal->insect->chicken->human is pretty good for eliminating parasites, though maybe not salmonella. [ETA] Most of what I said about chicken feed is also true of pigs, although their footprint is somewhere between the two extremes.

Robotbeat 6y ago
But where do the invertibrates get THEIR food from? Feed corn is super cheap per calorie (people sometimes burn feedcorn in stoves for heat), so it’s probably what you’d feed the invertebrates. Edit: Yup, insect farms typically use grains as the feed. Grains which you could eat directly (after baking or cooking, of course) which would be more calorically efficient. https://www.theatlantic.com/health/archive/2015/09/americas-cricket-farmers/406843/ https://www.theatlantic.com/health/archive/2015/09/americas-...
- hinkley 6y ago
  I can't deny that feed corn has good shelf life (they store it outside under a tarp when the silos are full). But there are other food streams that don't necessarily pass inspection, especially for perishable foods. I know from a couple days at a food bank that cows can eat pretty bad apples, but there are badness levels that would be much safer for grubs or larvae to eat. Feed corn takes a lot of water though, and I don't know how much longer we'll have that.
  - Robotbeat 6y ago
    Typically insects used for human consumption are fed grains (such as feed corn), but with a conversion efficiency making the problem worse. True that smaller operations, family farms, and homesteads could take advantage of waste streams like that, but that is kind of a logistical nightmare for feeding of large urban/suburban populations.
    - hinkley 6y ago
      We need to stop thinking we are going to fix our many many problems that we have created through a multitude of individual decisions by finding One Weird Trick. It's magic thinking, and we're supposed to be grown-ups. Whatever that means. Solutions don't have to scale infinitely. They just have to scale.
- boo_boo 6y ago
  > Yup, insect farms typically use grains as the feed. Grains which you could eat directly (after baking or cooking, of course) which would be more calorically efficient. Black soldier fly larvae can be fed almost any organic matter, including waste. The use of grain as feed for insect farms (which can largely be attributed to grain subsidies) doesn't imply it's the end-all energy input.

Robotbeat 6y ago

Less than 28% of the American diet is from animals (meat, eggs, and dairy) by calorie. https://grist.org/industrial-agriculture/2011-04-05-american-diet-one-chart-lots-of-fats-sugars/ https://grist.org/industrial-agriculture/2011-04-05-american...

shafyy 6y ago

We get 18% of calories and 37% of protein from animal foods (same source as above).