Good luck! I lost baby weight plus some and kept it off for years (including through another pregnancy) about 12 years ago. I did well at maintaining until about 18 months ago when my life hit some big snags and I gained a lot of weight. So, I'm working on it again, 12 years older (and 40 is not the new 30 when it comes to metabolism, LOL!) and hopefully I can have the same great results. I think one of the most important things is to read the book! I've read it probably 5-6 times, and I'm reading it again. It not only reminds me of the parts of the plan, but is good inspiration.
As far as the soda, everyone is different. I've never noticed that it effects me in a good or bad way, ame with caffeine, although I have very little and not on a regular basis, so maybe if I did I would notice.