The first couple of weeks, all sorts of strange things happen to your mouth digestive system and just about every other part of you! I had a thick build-up of white stuff on my tongue, which has now, thank goodness, gone completely. Basically, my theory is that we have all spent years throwing any old processed rubbish in our mouths and for the first week or so, all of our systems need to spend a lot of time re-adjusting to this new, nutritionally balanced eating plan. That means that things are bound to go a little haywire there for a while. Stick with it and things should quickly settle down. If it goes on for too long it might be a good idea to see your dentist as plaque build-up can lead to all sorts of nasty bacteria settling in your mouth and causing halitosis. We have enough of a problem with ketosis breath, so that would be doubly unappealing!