I've decided to give the SBD a go. I own the older book (I ordered it a long time ago and never read it). Is it ok to go by the old book? My library is going through some crazy system change and I can't order any books right now. Is there a lot of differences between the old one and the new other than a few changes on the foods list? Should I go by the new food list even if I'm reading the old book?