. . though my policy was to accept anything served when I was a guest. When I started out the protein thing was a major concern. Turned out, due to protein industry pressure, the government's minimum protein recommendation at the time bordered on the danger zone. It has been significantly reduced since then but still is far from minimal.
Turned out getting enough protein wasn't a problem, and health gurus' shrill warnings that every meal must be protein balanced also fell to research. If you're balanced within three meals that's probably sufficient. Grains vs. beans are, of course the classic balancers. Corn is a particularly unbalanced protein source and lots of beans are needed in corn dependent cultures.
Current results, both research and demographic, point to the "Medeterranean diet" as the healthiest. This diet is low in meat, high in vegetables, olive oil, wine, rice and pasta, and easy to make entirely vegetarian without losing flavor. Turkish is also good for that.