 Why doesn't the narrator care about having eaten in the past day and a half?
All my great-grandfathers have it. It had happened a few times right after I first found him, but now it was worse. They told everything I needed to know to become the most powerful man in the Solar Federation. I remembered that he was somebody very important whose name and work I had once known, even if now I knew him only as Doc. Earth-norm humans sometimes have the addiction to a slight extent, but I knew that as a Centurian I had it infinitely worse. Caffeine affected my metabolism like a pure alkaloid. They have a little caffeine in them—not enough, never enough, but better than nothing. I surrounded it like an ameba, almost in a single movement of my jaws.
 He is preoccupied by his stronger need for coffee
 He does not actually need to eat to survive  He is an evolved human who does not actually need to eat to survive  Water is more important than food, so he needs to find that first  He is preoccupied by his stronger need for coffee