What an individual pursues as a desirable end depends upon what he conceives himself to be. - Ramanuja

The individual self is subject to beginningless nescience, which has brought about an accumulation of karma, of the nature of both merit and demerit. The flood of such karma causes his entry into four kinds of bodies — heavenly, human, animal and plant beginning with that of Brahma downwards. This ingression into bodies produces the delusion of identity with those respective bodies (and the consequent attachments and aversions). This delusion inevitably brings about all the fears inherent in the state of worldly existence. The entire body of Vedanta aims at the annihilation of these fears. To accomplish their annihilation they teach the following:

Entities other than Brahman can be objects of such cognitions of the nature of joy only to a finite extent and for limited duration. But Brahman is such that cognizing of him is an infinite and abiding joy. It is for this reason that the shruti [scripture] says, `Brahman is bliss’ ( II.6.) Since the form of cognition as joy is determined by its object, Brahman itself is joy.

When the food is pure the Sattva element gets purified, the memory becomes unwavering.