It is only because we have not rectified our entire bodies, that we digest and use the corporeality of the food. Whichever part of our bodies have not properly been humbled cannot receive directly from the life-force within the food and so they are forced to consume the food itself in order to derive life.
This humility is an aspect of Mosheh Rabbeinu who was utterly humble. Each of our 248 limbs and 365 sinews must expose their potential humility which is the nature of Mosheh Rabbeinu that is latent within that body part. When our whole body is in a state of awareness of its dependence on and recognition of HaShem's might, then we don't need to eat at all. This is how Mosheh survived for one hundred and twenty days on Sinai without eating or drinking.
The reason, he explains, that our digestive functions produce putrid/disgusting byproducts is to remind us of how lowly and dependent we truly are.
It seems to me that this is good to keep in mind during the time between Purim and Pesah when we are meant to work on perfecting our ability to eat in holiness.