Ketosis hit me on day 3 and I had a vague kind of feeling, but luckily no headaches or any other side effects. I had a furry tongue by day 4 which made me constantly want to drink and nothing would rid me of it! I invested in some listerine strips and some mouth wash which helped for all of 5 seconds!
I have to say, recently I have noticed that the 'furriness' has gone. I thought that would remain for the entire time I was on LT, either that or I just don't notice it anymore!