Hi Tina

I don't know the truth about what you are asking, but here is an interesting article you might want to look at:
http://www.lowcarbluxury.com/yogurt.html

Hope you find it helpful. I wondered about adding yogurt after reading it. The only reason to take a chance, IMHO, is to get the benefit of the live cultures, so you would have to read the label carefully anyway. Doing that, I discovered that different plain yogurts have different carb counts. Go figure. (literally)