Indeed you are correct about the
> contrast of energy and resource expense between plants and animals is staggering, even if you’re comparing a less demanding animal like chicken.
I would like to see this study[0][1] repeated for various types of beans and legumes:
> Pork, chicken, eggs, and dairy were all pretty similar, but beef was a different story. Compared to the average of the other four, beef required 28 times the area of land per calorie, 11 times the water for irrigation, six times the nitrogen fertilizer, and it resulted in five times the greenhouse gas emissions For reference, they calculated similar impacts for potatoes, wheat, and rice. Compared to the average of those, beef’s footprint ballooned to 160 times the land, eight times the water, 19 times the nitrogen fertilizer, and 11 times the greenhouse gas emissions. Per gram of protein, the story is largely the same except that potatoes, wheat, and rice have less of an advantage due to their lower protein content.
The math listed in the article doesn't completely check out, e.g. they imply that [pork, chicken, eggs, dairy] require 160x (beef:plants) / 28x (beef:chicken) = 5.3x times (chicken:plants) as much land as [potatoes, wheat, rice], which makes sense, but also imply that [pork, chicken, eggs, dairy] 8x (beef:plants) / 11x (beef:chicken) = 0.72x times (chicken:plants) as much water as [potatoes, wheat, rice]. It's not thermodynamically possible for chickens to use less water per calorie than their feedstock. I never opened the actual study[1] though, I'm assuming they have reasonable results inside the study.
I also think that analysis vs. protein is more relevant than vs. calories -- which is why I think they should be compared against high-protein plants like beans and legumes.
0: https://arstechnica.com/science/2014/07/among-meats-beef-has...
1: https://sci-hub.ru/10.1073/pnas.1402183111