The mental_floss blog has an interesting piece on the origins of cereal. Only a short bit of it is eco-related, so I’ll post that here (emphasis mine):
Meat Is Murder (on the Colon)
During the early 19th century, most Americans subsisted on a diet of pork, whiskey, and coffee. It was hell on the bowels, and to many Christian fundamentalists, hell on the soul, too. They believed that constipation was God’s punishment for eating meat. The diet was also blamed for fueling lust and laziness. To rid America of these vices, religious zealots spearheaded the country’s first vegetarian movement. In 1863, one member of this group, Dr. James Jackson, invented Granula, America’s first ready-to-eat, grain-based breakfast product. Better known as cereal, Jackson’s rock-hard breakfast bricks offered consumers a sin-free meat alternative that aimed to clear both conscience and bowels.
("Granula" was later changed to "granola" by one Dr. Kellogg, whose brother W.K. happened to invent cereal flakes in a "kitchen mishap.")
Anyway, the story goes on to explain how this "sin-free meat alternative" became the cartoon-covered boxes of sugar we know today. Fascinating, I think — plus the granola/vegetarian connection adds another layer to that whole "granola-hippie-enviro" association.
Semi-relatedly, here’s a link back to Tom Philpott’s review of organic breakfast cereals.