Hi Jane
I wonder if you need to read up on this a bit more - it's about giving up fructose specifically, so "carb" is a blanket term which is confusing you I think. Rather than me trying to summarise David's works on this topic here, maybe you could go over the basics on this website. Also his books are very informative, or you can find interviews on the internet that David has given which I've found very useful.
Good luck though, and well done for making it through the first (and hardest) weeks!
Sandra