> This implies higher requirements for protein and essential fatty acids. The body does not produce them, it must be brought in via animal proteins.

This is not true. Proteins and fatty acids are found in many common vegetables and it's not difficult to get a healthy balance of the above. Harvard's school of public health, recommends, "Get your protein from plants when possible" [1], and it's not hard to find many other sources suggesting the same.

1. https://www.hsph.harvard.edu/nutritionsource/what-should-you...