So throughout the self identifying vegan and vegetarian communities I have frequently heard that protein is irrelevant if you get enough calories and while I don't think I have seen "protein deficiencies" and see that it is not even something in relevant medical literature. I do think that the value of protein is under-represented and without too much knowledge.
I recently read a reference to a study showing that sheep given a supplement of 1 gram of cysteine daily had a 25% increase in wool production. Now that I think of it, I don't necessarily know that the a 25% increase in wool production is a good thing considering the question - is that 1 gram extra protein covering that extra wool production? If not, then it might be safe to assume that the extra cysteine is leading to an increase in overall energy expenditure on wool production - which may be undesirable and actually a bit of a trick; the sheep are used to eating the associated calories with that cysteine in order to produce the extra wool and now are doing it without the calories... but I'm just hypothesizing here.
So either way, we can see that protein can make a big difference. As a competitive athlete and person interested in great fitness I would like to know how much protein is ideal for me. I think it's possible that I'd do better on 80-90 grams instead of the world government recommended 55 grams. However, I also think it's possible I'd do better on 30 grams than 55 grams and see that protein is acidic and doesn't seem like something I want an excess of.
However, I might do better on the 80-90 grams because of the associated nutrients that come with it. I am not expecting to shift my diet to apricots in the winter because of their high protein intake. I will stay mostly seasonal (I am pretty much all local and eat bananas too). So if I decide hey 80-90 grams is a good idea, and add in two pounds a day of cabbage, spinach, or some other greens like kale I'm pretty sure I will have a host of good results from all the extra vitamins and minerals and extra joy of eating.