With this kind of diet, you want to be very well-hydrated. Dehydration is a problem for many reasons. For starters, if you are dehydrated your body may develop irregular bowel movements and you may have a harder time losing weight. You also will be putting your body through a new test and regimen so ensuring other parts are being well-nourished is key.  Aim to drink at least eight glasses of water a day. You should really be drinking more and if you are working out double that. The more you work out the more you sweat. It doesn't hurt to also throw a lemon in your water to add taste and detox qualities.