In a fast, as you probably know, it is forbidden to eat. So anything that would be halachicaly considered eating wouldn't be allowed. While reading some answers on this site, I found that chewing gum isn't halachicaly considered eating.
I've always thought that you can't chew gum on a fast. But how is this contradiction resolved? Can you actually chew gum on a fast?
Regular or flavored chewing gum is forbidden according to all sources I found but there are some permitting sugar-free flavorless gum which is apparently considered as a non-food then.
Many poskim forbid chewing gum without distinction, e.g., Ohel Moshe Vol. 2-113, Yalkut Yosef, Hillel Omer OC 278
R Eli Mansour cites R Ovadia Yossef forbidding regular chewing gum
Hacham Ovadia Yosef in his work Yabia Omer (vol. 7, Orah Haim 33) rules that if one chews gum coated with sugar or other sweetening agent, he must recite the Beracha of She’hakol. By the same token, it would be forbidden to chew sweet chewing gum on a fast day.
The reference to sweet chewing gum is because R Ovadia Yossef permits flavorless gum and is not concerned by excessive saliva production
When it comes to chewing gum on a fast day, Hacham Ovadia rules that if the gum has a sweet flavor (like most chewing gum does), then it may not be chewed on a fast day. Flavorless gum may be chewed, even it has the effect of increasing the amount of saliva in the mouth, since saliva is considered part of the body and it may be swallowed on a fast day.
R Eli Mansour brings another source permitting chewing gum more broadly
Hacham Ovadia Hedaya (1890-1969), in his work Yaskil Abdi, rules that chewing gum is not considered “eating,” and thus one does not recite a Beracha before he chews gum.
Yom Kippur (and Tisha bAv?) likely have stricter laws, see here for instance
Please CYLOR before chewing !
Note that most poskim believe a chewing gum needs a sheakol bracha with possible exceptions again for sugar-free gum.
Rav Yosef Messas in Mayim Chaim 2:340 writes that chewing gum on a fast is permissible. The basis for his answer comes from the Rama 567:3 who writes that one may chew on cinnamon sticks, and other such spices, except on Yom Kippur. He notes that the MA argues, nevertheless he writes all we have(need) is the Rama.
However, it should be noted that MB learns differently, and nowadays I don't know of a posek who would allow chewing gum on a fast.
If the packet of gum lists calories, those calories go in you and that is eating. If your gum has flavor and then loses it, that flavor goes into you. However, if you prechewed the gum and all the flavor was lost, you might be able to chew that.
The straightforward answer is NO. The definition of [fast][1] is the willful refrainment from eating for a period of time while the gums contain fructose and carbs. So as soon as you will chewing gum your fast will break.
The reason behind your fasting is the gladness of god, so you can’t chewing gum while fasting at all.
