Honey, Honey, Honey
You should probably start to get familiar with honey if you want to be able to quench that sweet tooth. It's the only sweetener allowed on the SCD, and it is added to almost every sweet or desert on the diet. Saccharine is occasionally allowed, but it's very chemical tasting and only lends itself well to sodas. I think you'll find that honey can actually add an extra dimension of flavor to your sweets that is easier on the gut.