You have gotten some great advice, and I just want to add that artificial sweeteners are terrible for you. For yogurt, you can buy plain yogurt in the quart tub (not vanilla, just plain) and add fresh or frozen fruit to it. Also, then adding a little bit of stevia to it will sweeten it up a tad if you need it a little sweeter.
Also, there is a product called slimsweet made from low glycemic fruit sugars, as well as xylitol and erithritol, which are naturally occuring sugars that are safe for diabetics.
Good luck!