Diet soda?

Le • Designer born and raised in Canada. Love mangos and doughnuts but not together.
I'm following a diabetic diet because I have pre diabetes. My nutritionist recommends I not consume fruit or vegetable juice, soda and milk. But diet soda is ok. 
That said, though it's not sugar that will elevate my glucose levels,artificial sweeteners aren't great for you in other ways.  
Does anyone else feel conflicted by diet recommendations for gestational diabetes that seem counter intuitive?