I had terrible flu like symptoms for first week I went low carb and I found that sipping vegetable bouillon made into a drink with hot water helped a lot. I got the idea from posts on this board and it appeared that it was thought that some of the symptoms are due to low salt intake so the salty drink balances this out. I'm sure any kind of stock cubes would be OK. Even vegemite in hot water (I was bought up on vegemite in NZ but not sure I could drink it though!)
It definitely made a huge difference to me.