SHAFAQNA – The Grand Ayatollah Safi answered a question about chewing a chewing gum whilst fasting.
Question: What is the ruling about chewing a chewing gum whilst fasting?
The Grand Ayatollah Safi: If it (chewing gum) has no flavour to enter the throat, fasting is correct; but this act (chewing) is not suitable for the one who is fasting and doing it, is not right.
Source: PERSIAN SHAFAQNA