I chew gum all the time and did all the times I was on CD. I was told it was ok but would hate for you to have it and be kicked out of Ketosis. I have the green wrigleys sugar free stuff and its never done me any harm.
Yeah when i was on CD i was told the reason you shouldnt have it is cos it makes you hungry....and more likely to cheat if your constantly starving. I sometimes have it tho and im still in ketosis, and its notmakin me more hungry. But...everyone reacts different to different things, so dont take my word as gospel haha xx