There are several threads now with some speculation about mainstream eating in the 1950s/60s. I'm going to post this as a separate thread because it may be of historic interest to others. The images are from a book, "Family Meals and Hospitality", by Lewis/Peckham/Hovey, 1960 edition. It was my high school Home Economics class book.
It used 7 food groups, not intended to be exhaustive:
This is breakfast:
This is a a picture of daily menus, with some interesting hints about expected lifestyle (like the thermos bottle). Note the comment that foods outside the basic 7 groups will also be used.