Chicle was originally used as a natural substitute for rubber, but by about 1890 it was best known as the main ingredient in chewing gum. During WW II, the search for a rubber substitute led to synthetic products replacing chicle both in rubber and chewing gum production. By taking the chicle out of our gum, we cease to support a renewable rainforest industry when we masticate: sapodilla sapping, which does not destroy the tree, is forest-friendly production.
Some absurdists have speculated that American fondness for chewing gum is responsible for the characteristic overdeveloped jaw and crab-apple cheeks of much of the US citzenry, but unfortunately the chicle workers in the sapodilla forests put paid to this theory, being as slack-jawed and hollow-cheeked as the rest of us.