Water is the best thing you can do, and guzzling it can really help with the weight loss. Drinking alot can also help with the bad breath that often comes with ketosis, and help to clear up the skin. Adiquet water also keeps water retention down and helps to flush toxins from the body.

You might try Diet Rite, as suggested, it is sweetend with splenda. Crystal lite in the bottle is also splenda sweetened.

For the gum, there are some brands that use Sugar alcohols instead. Wait until after induction, but then you can try some. Be careful though because sugar alcahols can effect some people. Also be sure that the gum chewing doesn't cause you to skip meals, or cut back on your water consumption.