It is far more efficient to eat animals and produce muscle. There aren't many world renowned athletes who are vegan for obvious reasons.

seeing as how veganism is not the default choice in most of the industrialized world, this is a misleading frame. it's also incorrect that it's more efficient to "eat animals" to produce muscle if we're being pedantic (as a vegetarian, however, this is not a meaningless distinction to me)— amino acids in dairy & eggs have a measurably higher bioavailability than those in meat, whether ranked by the PDCAAS or DIAAS https://web.archive.org/web/20151010170125/http://www.idf-is....

I assume they mean efficiency as in land area used etc. You have to put quite a lot of calories into a cow to get one calorie out.

That's a poor summary of the article you link, given that it says vegan diets are almost twice as efficient as the standard American diet. (It just also says that low-meat diets are even more efficient in terms of land use.)

Will you elaborate on the obvious reasons? Pretend they aren't obvious to me.

I'm interested in reading more about athletic advantages gained from consuming meat. Is there a reason that other sources of protein aren't giving the same benefit?

Here is a good article breaking it all down along with the amounts you would need to eat to get the same benefit.

https://www.muscleforlife.com/animal-protein-vs-plant-protei...

efficiency in that context means from a global of view, not how much time you're spending eating.