My friend has this unusual metabolism where she only gets hungry about every five days or so. She can go that long without eating and suffer no ill effects. She prefers to only eat according to that pattern. She genuinely doesn't get hungry. I know what you're thinking..."she's lying. She's anorexic. She needs help". She's definitely not. She is not thin - not fat either, but she is soft bodied and curvy, definitely not the look of someone malnourished. How does someone manage that? Is it just part of normal variation? Some people need to eat often or they get low blood sugar, others can go a whole day - is she just on the high end of that continuum? How does that work though? Where is someone getting the energy to function for four or five days on just still water?