Another "trick" is to drink water during the morning when you get a hunger feeling. You should drink plenty of water anyway, especially during the morning as you get somewhat dehydrated during the night. Having a bottle of water, plus a glass, sitting on your desk is best because it reduces the hurdle to drink some. You don't need to get up and walk to get something to drink. Of course can you also drink coffee and/or tea....However, each of us is different, so the amount of liquid that we feel comfortable with varies. Avoid advice such as "you must drink x liter/gallons of water per day".