The very first signs of "feeling" hungry usually means you're thirsty for water, not hungry for food.  A lot of people eat instead of drink (or drink something with calories), and that helps increase their calorie consumption leading to weight gain.<p>I've found keeping a bottle of water on me at all times works well.  Whenever I start to feel my mouth go dry I drink some.  I catch thirst this way before I even begin to feel thirsty.  It's like lubrication for your body.  If you don't drink enough of it, things seize up (you'll feel tired, get headaches, hampers athletic performance, etc...).<p>CamelBak makes some very nice bottles.  Sports Authority/Dick's Sporting Goods usually carry them:  <a href="http://www.amazon.com/CamelBak-BPA-Free-Choose-Re-Use-Better/dp/B001PKV6E8" rel="nofollow">http://www.amazon.com/CamelBak-BPA-Free-Choose-Re-Use-Better...</a><p>Nathan also makes a good one:  <a href="http://www.amazon.com/Nathan-500-ml-Bottle-Straw-Royal/dp/B001L417XI" rel="nofollow">http://www.amazon.com/Nathan-500-ml-Bottle-Straw-Royal/dp/B0...</a><p>Buy like two or three of them.  Fill them up in the morning and put them in a fridge.  Keep one by your side at all times.  Once it's empty, grab another from your fridge, drink as needed, repeat.<p>Keeping the water "ice cold" is important too.  It's so much easier to drink cool water than warm.  Probably something derived from evolution where humans had better luck drinking cold water from a running stream than warm water from a sitting puddle from a rain storm.  I always throw a few ice cubes in once I pull a bottle out of the fridge.