I read the book "Food for Fitness", Rodale Press, in the mid 70s. A lot of good stuff there, much of which we are now seeing 40 years later from the science/medical communities.
On part that I took to heart and have never regretted was its take on protein requirements. The book stressed that unless were were actively building muscle (and for a bike racer, that is only early season; after that it is maintenance and recovery), our protein needs were small and easily met and that more meant burdening the digestive system which required shunting blood flow away from muscles that needed repair/recovery to the stomach. In other words, too much protein was interfering with the recovery of those muscles we think we are eating it for.
Based on that book, I settles in at 50 grams/day for my 150 lbs as being comfortable overkill. 50 grams/day is easily met, no "protein" foods required and I have never taken any. I eat 3 eggs a week, most of a quart of yogurt, around a pound of cheese and plenty of beans. Eat out (usually no meat, perhaps a little chicken on pizza) several times a week. In my racing days, there were no animal products except cheese, yogurt and eggs in roughly the above amounts except ~8oz yogurt/day. And as I said in another forum yesterday, wow! did I feel good on that diet!
Ben