Granola was not, in fact, invented by hippies in the 1960s but they did popularize the name.
The story of this cereal begins a century earlier, with health food advocates of the 1860s.
At his health sanitarium in upstate New York, Dr. James C. Jackson created "granula" for his patients. Jackson formed his "granula" by breaking up sheets of twice-baked whole grain flour (then called graham flour after its developer, Sylvester Graham).
A decade later, Dr. Jackson sued Dr. John Harvey Kellogg of the Battle Creek Sanitarium for calling his own similar invention "granula." Kellogg renamed his version granola, but never really marketed it.
Back-to-basics food lovers revived Kellogg's coinage in the 1960s; the generic usage of the word granola appeared in print in 1970.