Gum can only give you gas if you chew with your mouth
I certainly can't do sugar-free gum, even though it's supposed to be good for your teeth because it keeps your saliva production up, which reduces the bacteria which cause cavities and even gum disease. But they say chewing on anything, even a rubberband, will do the same thing. Oh, and so will kissing.
I think all I need to do is put a package of SweeTarts next to my computer monitor. For whatever reason, just thinking about eating one makes my mouth water. I guess because they are tart.