I'm also this way - and it stems from boredom (slow at work right now), and my running (I run a LOT). And my office has a treat drawer not 5 ft from me at all times. I have a very fine line to watch as to whether I'm hungry, thirsty, or bored... but at least I know it. I always try the same method:
1. Drink a cup of water. Did it help?
2. Get up and go for a small walk around the office. Did it help?
3. Try to find a 'make work project' for a bit. Did it help?
4. Chew a piece of gum. Did it help?
5. Eat a healthy snack from my cubicle. Did it help?
and if none of that helped at all - I get something small from the treat drawer. Some trail mix with M&Ms in it, some jelly beans, a small chocolate bar - everything is measured out and tracked. If that didn't help, then the work gods are telling me to get my @$$ home.