What's Hunger?

I've been fasting for good chunks of the last several days to better understand hunger, both mentally and physiologically. I found the following to be true for me:

• I can go more than 24 hours between eating solid foods without hunger becoming physically painful (a "stage 2" full)
• Being busy, physically and/or mentally, keeps me from thinking about being hungry/eating
• I'm amazed by how conditioned I am to eat at certain times (8, noon, 6)
• Feeling the need to eat is driven more by a state of being, e.g. boredom, anticipation, than actual physical hunger.
• I get to a point of being physically uncomfortable from being hungry after about 13 hours.
• Taking in fluids produces a full feeling that can last several hours
• Chewing gum has a hunger abating effect
• Extreme hunger involves feelings of nausea, a tightness in the throat area and a slight headache.

I'm trying to continue this experiment for a couple more days to see what happens.