Cannan was the "Land of milk and honey."
Northern Israel was the land of milk, where goats and sheep were herded and farming took place. The north, occupied by the ten tribes of "Israel" is better farmland, much more lush than the south. Southern Israel, the land of the tribes of Judah and Benjamin, is more arid, the land of bees and honey. Milk in the north, honey in the south.
Recall that during the divided kingdom, the ten tribes in the north (Land of Israel) were seperated and to a certain extent at war with the two southern tribes of Judah and Benjamin (Land of Judah). At the very beginning of the divided kingdom, right after Solomon died, king Rehoboam in the north, set up two golden calfs, one in Bethel and one in Dan, saying...
**"The kingdom will return to David's house. If now this people go up to offer sacrifices in the temple of the LORD in Jerusalem, the hearts of this people will return to their master, Rehoboam, king of Judah, and they will kill me." After taking counsel, the king made two calves of gold and said to the people: "You have been going up to Jerusalem long enough. Here is your God, O Israel, who brought you up from the land of Egypt." And he put one in Bethel, the other in Dan.* (1 Kings 12:26-29)*
King Rehoboam basically took the ten northern tribes back to the time of worshipping the golden calf at Mt. Sinai, throwing away centuries of mosaic law and abandoning God's laws about temple worship. Spiritually, the north was dead and Bethel became a center of the worst kind of pagan worship. Elijiah and Elisha the prophets were from the south but operated in the north, preaching to the pagans there.
After the Babylonian exile, the vast majority of the ten northern tribes didn't even bother to come home. They had completely abandoned their identity as part of the nation of Israel and thus as God's chosen people. They had become like the nations around them in diet, language, and pagan religion and just stayed in Babylon. Most of the nation of Judah however, returned to the land in the south to rebuild Jerusalem and the temple and to begin temple worship again. And that, I think, is the background for John the Baptist eating locust and wild honey.
John is the "New Elijiah", a prophet like Elijiah and Elisha, sent to herald the advent of the Christ. Since Cannan was the "Land of milk and honey", living in the desert and eating locuts and honey, rather than living in a lush forest eating milk and meat, was a way to identify what kind of prophet John was and where he was from. Elijiah and Elisha were from the south but operated in "enemy territory", preaching the God of Israel to the worst kind of pagans. And such was John. John acted the same way, saying "You brood of vipers!" and such things to the Pharisees. It's important to note that Jesus was a prophet from the south, the land of Judah, as well and spent 40 days in the desert.
The stories in the Old Testament are so interesting, and a good Bible study helps to put the New Testament in its proper perspective, as fulfillment of the Old Testament. One really can't fully understand the New Testament until they understand the history, timeline, and narrative story in the Old Testament.