Fuck, fuck, fuck; this explains so much.
Of all types, INFJs (and INTJs) are the most detached and disconnected from their own bodies. Not only is their S function inferior, but INFJs do not have Si in their functional stack (Or, more technically, Si might be considered their last/eighth function), which is the function that contributes an internal sense of one’s body. INFJs commonly report being plagued by the sense that their body is not really a part of them. In his book, Jung’s Four and Some Philosophers, Thomas King writes of the Introverted Intuitive: “his hands are alien to him and his body unfamiliar.”
Because of their detachment from their physicality, INFJs may have nightmares about unexpected declines in their health. One INFJ, for instance, recounted to me his recurrent dreams of his teeth falling out. Another reported her fear that she might develop a disease and be unaware or ignorant of the symptoms until it was too late. Other INFJs report worrying that their obliviousness to physical reality might compromise the safety or well-being of their children. INFJs may forget to eat regularly and appear undernourished, or they may overeat because of lack of attention to how much they are eating. To compensate for this mind-body disconnect, they may subject themselves to overly strict, even obsessive, regimens of diet and exercise. Like other types, when trying deal with inferior-related issues, they are wont to go to extremes.