[rsynnott]

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.

[jriot]

https://qz.com/749443/being-vegan-isnt-as-environmentally-fr...

Being vegan is that efficient either.

[tgb]

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.)