In the Bhagavad-gītā it is clearly explained that there are three kinds of activities according to the different modes of nature: the activities of goodness, the activities of passion, the activities of ignorance. Similarly, there are three kinds of eatables also: eatables in goodness, eatables on passion, eatables on ignorance.
They're all clearly described, and if we properly utilize the instructions of the Bhagavad-gītā, then our whole life will become purified and ultimately we shall (be) able to reach the destination: yad gatvā na nivartante tad dhāma paramaṁ mama (BG 15.6). That information is given in the Bhagavad-gītā, that beyond this spiritual . . . material sky, there is another, spiritual sky: that is called sanātana sky. In this sky, this covered sky, we find everything temporary. It is manifested, it stays for some time, gives us some by-product, and then it becomes dwindling and then vanishes. That is the law of this material world. You take this body, you take a fruit or anything what is created here, it has got its annihilation at the end.
So beyond this temporary world there is another world, for which the information is there, that paras tasmāt tu bhāvaḥ anyaḥ (BG 8.20). There is another nature which is eternal, sanātana. Which is eternal. And the jiva . . . jīva is also described as sanātana. Mamaivāṁśo jīva-bhūtaḥ jīva-loke sanātanaḥ (BG 15.7). Sanātana. Sanātana means eternal. And the Lord is also described as sanātana in the Eleventh Chapter.
So because we have got intimate relation with the Lord and we are all qualitatively one . . . the sanātana-dhama and the sanātana Supreme Personality and the sanātana living entities, they are on the same qualitatively plane. Therefore the whole target of Bhagavad-gītā is to revive our sanātana occupation, or sanātana . . . that is called sanātana-dharma, or eternal occupation of the living entity.
We are now temporarily engaged in different activities, and all these activities being purified, when we give up all these temporary activities, sarva-dharmān parityajya (BG 18.66), and when we take up the activity as desired by the Supreme Lord, that is called our pure life.