The reason for the water is so that you are full throughout the day. The other reason for water is that normally us Amerifats drink Coke, sugary drinks, alcoholic beverages, etc. this is one of the quickest ways to gain weight. If you only drink water all day then you'll feel better, be less hungry and won't permit excess calories in the form of bad drinks. A gallon is really an exaggeration but you should be drinking a lot. 0 calorie drinks are permitted though.
Good for you for eating at 5 and then eating at 8. I don't eat dinner until very very late sometimes 9 or 10 and I am eating lunch the next day at 12.
The calorie thing is the most true. I think a lot of people forget that when dealing with fads lol.