As Coke Zero has no carbs and no citric acid, I have been having it as a once a week treat for the past two weeks. It has absolutely no bad side effect for me at all and it's really nice to have something that feels a bit naughty. It's not for everyone and I guess you'd need to try it and see if it affects you - if it does, abstain, if it doesn't - then have it as an occasional treat. x If it means the difference between keeping you on the diet, then I think it's worth a try x