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Comment by dualogy | Hacker News Reader

Pff, "modern society". Most hunting populations have been calculated to yield 10kcals of food for every 1kcal of expenditure --- our fancy modern fuels OTOH result in more like 1kcal food yield per (non-edible of course) 10kcal expenditure. Not exact figures of course but the difference is that profound. "Human power" thus "wins", then --- but not to "run modern society", of course.

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Here is a guy who has experimented living 'energy positive' for many years[1]. Meaning he tries to get more energy out of farming that he puts into it. In his calculations it does not make sense even to use a horse. Seems pretty tough, I think hunting and gathering would be easier way to go if you had access to the land.

Good writeup, but unfortunately in finnish.

[1]http://rihmasto.fi/artikkelit/elamamme-perusteista

(google translate) https://translate.googleusercontent.com/translate_c?depth=2&...

How is this a useful comparison? It's 10kcals of ingested food per 1kcal of energy the hunter expends (not including e.g. the energy of the game). By that measure, I'm super efficient cause I buy food at the supermarket, and don't really expend any energy for it. That number has nothing to do with the second 1kcal/10kcal modern figure.

You're not wrong, it "doesn't really matter" as long as our fuels do keep up with our species' (consumption, production & reproduction) growth.

Exactly. Going back to hunter-gatherer and living off the land like that is hardly sustainable with the current population: Earth has 5.7e7 sq mi surface, but 7e9 people, i.e. 8.1e-3 sq mi/person. Hunter/gathers seem to need (after a short google session) need around 1e-2 (Tropical) to 1e2 sq mi (Savannah) per person.

This might be more accessible if you weren't using scientific notation. They aren't exactly astronomical numbers

That doesn't seem right - surely a modern animal farm yields more food per energy expended than a group of hunters?

Anthropology classes teach that the parent comment is true: hunter-gatherer societies are much more energy efficient. Every step of modernization, from animal to machine power, decreases energy efficiency but increases intensity: food can be made more quickly and in less space. Consider that animals are more powerful, but require food and water of their own. Tractors are more powerful still, but require fuel, steel, and huge industries that bring those two together.

The best citation I have off hand is this https://anthropology.artsci.wustl.edu/courses/wucrsl/L48/361...

It does make sense when you consider where the energy all comes from: the sun.

Plants absorb solar energy and store it as chemical energy. Animals roam far and wide to eat those plants, collecting the chemical energy in one place- themselves. Then human hunters come along and simply 'pick' the energy from the dense source that is the animal.

Now, the humans don't need to do much work because the energy is all in one place (they just need to find that one place). But the energy itself was collected over a huge area.

Tractors and fertilizer inputs to the feed, of which only a fraction ends up in the meat (https://en.wikipedia.org/wiki/Feed_conversion_ratio). Things like eggs and crickets are very efficient, with about 1/2 the feed energy ending up in the product.

For beef it is more like 10-15% of the feed energy.

Interesting stuff.

I guess the advantage is that you don't have to rely on nature and chance to get that food, since you literally create it from scratch.

citation needed

I don't think so. Only 10-20% of the energy we get from food can be used for manual labour, and that's neglecting rest and sleeping periods. If what GP is saying wasn't true, hunter populations wouldn't be able to survive.

This is also why reduced calorie intake is much more effective than increased activity if you want to lose weight.

I think the fatal flaw in the argument here is that the hunted animals are seen as a magic free resource; in reality of course they're a limited resource taking up valuable land, and we could never sustain 7bn people or anything like it in this way.

How's that a "flaw", I wasn't advocating one thing or another. Of course 7.4 billion and growing cannot feasibly all enjoy the bountyful abundance of game and leisurely pace of our pre-neolithic ancestors (or North-American natives etc) =)

It's still a plus to acquire just another added perspective on fuel yields for different types of human societies and lifestyles

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