First of all, one should know why he is fasting. It is important to understand that the fast is not a nuisance! It is a mitzvah, and this mitzvah facilitates all of the good that we will derive from this holy day. Personally, I am really looking forward to this chance to divorce myself from worldly matters and to concentrate on spiritual things.
I always tell anyone who is willing to listen that it is much more important to drink before the fast than to eat before the fast. Here is someone who agrees with me:
While a healthy adult can generally survive for weeks without food, dehydration can set in within a few days. It's no surprise then that most of the discomfort of fasting is caused by lack of water not the lack of food. To help reduce the effects of dehydration during a fast it is critical to properly hydrate beforehand.Not eating for a day makes your stomach growl. Big deal! However, if you did not drink enough before the fast, do not be surprised if you get a nasty headache or worse! So drink!
G'mar Hatimah Tovah!