The second myth to set aside is the myth that plant foods don't provide "complete protein." They do. Potatoes are an example. You can get all the protein you need from potatoes. Add fruit and vegetables and you will get plenty of protein in both quantity and variety. (An assumption here is that you have a healthy appetite.)
Those are my conclusions. I am a layman. I rely on the testimony (related to my own experiences) of individuals I trust as sources. For a start on exploring these issues, see Dr. McDougall's articles on protein, in his newsletter. For instance:
PROTEINS AS A CAUSE? When I saw the first results of my food testing, I wondered if all proteins might be the cause of my inflammation problems. However, further testing indicated that, for me, proteins in alkaline-producing foods do not cause flare-ups, even when eaten in normal quantities at every meal during the six-meal test.
I know now that alkaline-producing foods, as shown in the PRAL list, must be my only source of protein. To make sure I get all the different kinds of proteins (amino-acids) required for health, I try to eat a very wide variety of fruits, vegetables, starchy roots and starchy gourds.