There is plenty looking at how it scales up and they account for nutrition
we show that plant-based replacements for each of the major animal categories in the United States (beef, pork, dairy, poultry, and eggs) can produce twofold to 20-fold more nutritionally similar food per unit cropland. Replacing all animal-based items with plant-based replacement diets can add enough food to feed 350 million additional people, more than the expected benefits of eliminating all supply chain food loss.
The research suggests that it’s possible to feed everyone in the world a nutritious diet on existing croplands, but only if we saw a widespread shift towards plant-based diets.
[…]
If everyone shifted to a plant-based diet we would reduce global land use for agriculture by 75%. This large reduction of agricultural land use would be possible thanks to a reduction in land used for grazing and a smaller need for land to grow crops.
Before anyone mentions something like grass-fed production let’s note that grass-fed production very much doesn’t scale and has enormous land use giving high pressure for deforestation as well
We model a nationwide transition [in the US] from grain- to grass-finishing systems using demographics of present-day beef cattle. In order to produce the same quantity of beef as the present-day system, we find that a nationwide shift to exclusively grass-fed beef would require increasing the national cattle herd from 77 to 100 million cattle, an increase of 30%. We also find that the current pastureland grass resource can support only 27% of the current beef supply (27 million cattle), an amount 30% smaller than prior estimates
[…]
If beef consumption is not reduced and is instead satisfied by greater imports of grass-fed beef, a switch to purely grass-fed systems would likely result in higher environmental costs, including higher overall
methane emissions. Thus, only reductions in beef consumption can guarantee reductions in the environmental impact of US food systems.
There is plenty looking at how it scales up and they account for nutrition
https://www.pnas.org/doi/abs/10.1073/pnas.1713820115
https://ourworldindata.org/land-use-diets
This is because it takes a lot of human-edible feed to produce animal products
https://www.sciencedirect.com/science/article/abs/pii/S2211912416300013
Before anyone mentions something like grass-fed production let’s note that grass-fed production very much doesn’t scale and has enormous land use giving high pressure for deforestation as well
https://iopscience.iop.org/article/10.1088/1748-9326/aad401