I ran across a drink mix similar to crystal light made by Hansen's Beverage Company. It's the individual packets that you add to a bottle of water. 5 calories in each with 1 carb (0 sugars). The ingredient list is maltodextrin, citric acid, fruit and vegetable juice powder, natural flavors, ascorbic acid (vitamin c), stevia extract (rebaudioside a), calcium carbonate, carrageenan, tricalcium phosphate, and calcium silicate.
I've just finished up day 5 on Phase 3. Been extremely stable so far. Used a packet of sweet n low here and there, but for the most part I've stuck to liquid stevia. I have had 1 shot of tequila with no problem ..but then it was only one shot.