I've never tried Stevia, though I am curious about it.
There aren't any recipes in the book for baked products, or references to baking that I've run across. But from some of the replies by the nutritionist on their forum, I get the impression that little bits of some things are ok, as long as you don't get carried away, and make reasonable choices. She explained that some ingredients are added for flavor or variety, even if they are not on your food list. You just have to be careful.
I'm not big on diets with strict taboo lists. It's food, not drugs. It's my impression that this book understands that leniency is necessary sometimes.
Many baked goods require a small amount of sugar to rise properly or achieve the right texture. Two teaspoons of sugar in a bread recipe isnt going to hurt anyone. It's not like we're baking a cake, right?
I'd try to search their website to find out, but all I'm getting are errors. They've had more technical problems this week than we have!