Humans use tiny amounts of energy compared to even a smartphone. And they consume the vast majority of that energy regardless of whether they're lounging in bed or pouring over medical records.
I remembered there was some analogy about a person doing some work walking, with an average diet, versus using an internal combustion engine. In terms of carbon emissions.
The engine came up more favorably.
Turns out, eating any meat and industrial agriculture transportation are really heavy.
I think you may be thinking of the question, "how much greenhouse gas does it take to move a human X miles if they are self-powered versus using an ICE?"
> our estimates suggest that the net emissions associated with the ‘fuel’ required for driving, walking, and cycling may be comparable in some settings
With the caveat that they're looking at *per-mile* emissions, and nobody in the developed world is walking 60 miles to and from work every day.
However there's an important clarification to your recollection.
- You're correct that eating meat (and dairy) is very carbon-intensive.
- You're not correct that agricultural transportation is significant. It doesn't even make it into the paper above, as far as I could find. Agricultural transportation, even things like flying blueberries to California from Chile, is negligible compared to the carbon cost of food.
This sounds like a false equivalency to me... why are you comparing humans and their support networks... but the engine doesn't also get the same comparison? What about the factories that make them for example? All the gas station infrastructure etc.?