There is now sugar free, no caffeine Coke. Start by using 1/3 of this to 2/3 coke. More or less same taste, different caff. Then go w more of the no sugar/no caff stuff until you are "weaned". Try sugar free root beer. Or lemonade w fruit spike, use sweeteners, not sugar. Go for flavor.

diet coke?

Try sparkling waters, that way you still get the bubbly sensation of the carbonation while cutting out the sugar addiction of sodas. There are many flavors, ot you can get the plain kind and add liquid enhancers like mio or crystal light.

Going throw that myself

Slowly - be ready for the headaches (caffeine and sugar withdrawal).