Nutritional facts are misrepresented by the Guardian in this article and in the primary source of the research: https://www.cerealmarino.com/wp-content/uploads/2021/01/APON... 50% more protein “per grain” is a comparison I’ve heard here first. The intro of the paper claims “13% protein” but its comparison table states “10.1% protein”. In comparison, regular wheat has around 12.6% protein, while Einkorn wheat contains…
Yes but there's a catch, and you can see it in p 24 of the reference you linked.
Legumes are low on Methionine. Grains are low on Lysine. Ideally a consumption of both is needed to balance things out. (Hence why these "protein $thing" stuff on the supermarket is 100% marketing gimmick since they use the cheapest sources available - soy usually)
(Also of course this is the overall proportion, it says nothing about protein/gram. Yes, broccoli is high protein, but how much broccoli do you need to eat to match the content a steak? - answered on p.27 actually)
Edit: "oh look Gorillas and Cows are vegetarian" Cows actually have their intestinal flora make the proteins for them ;)