The Modes of Nature

The Bhagavad-gita informs us that all conditioned souls are forced to act helplessly by the impulses born of the modes of material nature.1 The soul is thinking that he is acting by his own volition but in actuality the modes are shaping the soul's desires and actions.

There are three modes of nature: goodness, passion, and ignorance. According to the specific combination of the three modes that a soul is affected by, he acts accordingly. The three modes combine to provide the impulses for every conceivable type of activity in this world, just as the three primary colours can be combined to yield all the colours of the spectrum.

According to the combination of modes, one is attracted to certain types of eatables. For example, the pig is very enthusiastic to partake of stool (which human beings consider abominable), because the pig loves food in the mode of ignorance. Food in the mode of goodness is sweet, juicy, fattening, and palatable.2 Food in the mode of passion is too bitter, too sour, too salty, pungent, dry, and hot.3 Food in the mode of ignorance is decomposed, tasteless, stale, putrid, and unclean (such as meat).4

A devotee is only interested in eating food that has been offered to Krishna which purifies his consciousness, and helps him in his spiritual progress.
1. Bhagavad-gita 3.5
2. Bhagavad-gita 17.8
3. Bhagavad-gita 17.9
4. Bhagavad-gita 17.10