Also, I like other types such as Lima and string beans. But how did the common expression “full of beans” get started. It figuratively has the same meaning as: “full of prunes.” They are used to mean being energetic and enthusiastic about something.
Also, “full of oats” or “feeling one’s oats” carries the same meaning of being peppy, lively, and in high spirits. It is believed that feeding horses beans or oats for fodder was where two of those expressions came from.
A horse fed beans (probably still in shells) or oats seemed to regain their energy. It is believed that ancient Romans fed their horses beans.
The “full of prunes” saying came later. It can also mean: acting foolishly and talking none sense. The substitution of “prunes” came about seventy or more years ago (From “Heavens to Betsy,” 1955, Harper & Row, by Charles Earle funk.
Dub Mowery is a Gospel preacher in the Church of Christ. A native of Southeast Oklahoma, he is the author of Colloquial Sayings & Expressions (Morris Publishing, 2008)