I think you're correct that the energy efficiency of a human exceeds that of current computers, but I think it's a bit more complicated than a first order calorie count.
How many joules go into producing those 900 calories? Like in terms of growing the food, from fertilizer production to tractor fuel, to feeding the farmer, to shipping the food, packaging it, storing it at the appropriate temperature, the ratio of spoiled food to actually consumed, the energy to cook it, all of that isn't counted in that simple 900 calorie measurement.
I've been thinking about this for a while now but I haven't been able to quantify it so maybe someone reading this comment can help.
> How many joules go into producing those 900 calories?
I think what you're getting at is question about conversion efficiencies, from solar radiation to whatever the computing-machine needs.
However, your description seems to risk double-counting things: You can't just sum up the inputs of each step, because (most of) the same energy is flowing onwards.
I don't think it makes sense to include all of that in the calculation. A human doesn't need all of that, they just need 900 calories. You can just eat berries, no need to cook anything, for example.
A human may not technically need all that but the humans who do exist in our society do.
A measurement of a hypothetical human foraging in the bush is a useful one but a much more useful one is the energy expenditure to keep a human alive in our society.
> A measurement of a hypothetical human foraging in the bush is a useful one but a much more useful one is the energy expenditure to keep a human alive in our society.
Which society? An American one? A German one? What about the iPads manufactured in China for both of them? A human of what income? If you do not draw the boundaries of the system you want to observe, asking how much energy that system uses is not very sensible.
I think more importantly is that uncooked food is harder to digest, so we need more of it.
Most years I pick free blackberries growing wild in the city. Won't scale to all of us, not seasonal, and I'd need to eat 6kg of them a day for my RDA of calories, and 12x my RDA of dietary fibre sounds unwise, but that kind of thing is how we existed before farming.
> Even if they could, where are those berries gonna come from?
By that logic, the "true cost" of boiling a cup of water for my tea somehow involves the Big Bang and rest of the formation of the observable universe up until now.
Berries are missing essential amino acids, essential fatty acids, and essential vitamins. You could live on them for a while, I guess. Actually you can live without eating at all for a while. Both would lead to a painful death though.
The most glaring one is that current LLMs are many, many orders of magnitude away from working on the equivalent of 900 calories per day of energy.