"Not by Brains Alone" is the title of a class I heard about at work. Sound familiar? "Not by bread alone" is a Biblical concept having to do with the idea that we need more than physical food for our sustenance. There's nothing wrong with the class title. My dad and I were discussing how many concepts and phrases we use now that come from the Bible and I thought if it when I saw the email on the class.
Here's a great link on the Bible's Influence on American Culture. It is really interesting to note how many words, phrases, and ideas come from the Bible.