Perhaps one of the reasons is that I need less and less food so it seems i should be aware of what that small amount of food is.
Exactly my same concern
anyway, I think the B12 concern is soon solved in a natural way, as I've written in the thread on B12 (except for vegans, who most probably need supplements).
I'm a little more concerned about iron and zinc, but I'm researching that. The best vegetarian source for iron are probably lentils. I can eat only very modest amounts of them though. Other sources are some nuts and seeds. Bitter chocolate and unsweetend cocoa are good sources for iron, zinc, magnesium and other metals, and almonds are very rich in Mg and walnuts are rich in Zn.
Proteins after a certain age are needed in small amounts, probably one half or one quarter of the FDA RDI, depending on physical activity. I'm going to research that as well.
mccoy thanks for the info on walnuts. I love walnuts but they're kind of $$$. Did not know they had zinc in them.