Just curious - have you tried drinking cold (around 2 degrees centigrade) water frequently throughout the day (about 500ml per hour)? And drinking about a liter of cold water after waking? Eating you first meal soon after waking may also be advisable.

Your sleep will most likely be disturbed with visits to the toilet, but doing so may increase your resting metabolism. The logic goes that with all that cold water intake, you'll always be hydrated, and your body must maintain a faster metabolism in order to keep your temperature at equilibrium. The water also makes you feel full more easily, helping to better control desired calorie intake.