This song as with any typical fruit based ballad is a simple story : boy meets fruit, boy falls in love with fruit. Most see it as a bad idea, and the relationship is forbidden by the boys family. This only serves to strengthen the lovers bonds, as if it is an addiction.
After some time, the boy starts seeing other fruit then not long after that his lust for more is unquenchable. Soon the boy has a 9-10 apple a day habit, along with assorted peices of tropical fruit "just to keep his head together."
All is soon put right when a noble doctor steps in and gets the boy back onto a more socially acceptable "5 a day" diet.