Is it a Sin?

Q: Is it a sin if a person who practises vegetarianism, still knows how non-vegetarian food tastes like? 

A: Before I could answer your question, I would, first, have to define what sin is. In the words of Swamy Sivananda Maharaj, "sin is an evil deed. Sin is willful violation of the laws of morality and religion. It is transgression of the Law of God....Hurting another is sin...Selfishness is sin... Robbing others' property is sin...that which pulls you down is vice or sin.... that which makes you a worldly man is sin....that which taints your heart is sin.... that which brings restlessness, dissatisfaction, depression, and contraction of heart, is vice....mischief-mongering is sin...hating others is sin... lust is sin....falsehood is sin....miserliness is sin .... weakness is sin.... cowardice is sin....That which you are ashamed to do in public is a sin. That which you dare not admit before your Guru is a sin....

"Learn to discriminate between virtue and sin, and become wise. The Antaryamin will guide you rightly; hear Him....."Sin is expiated by self-punishment such as fasting, Japa, penance, meditation, and repentance with a contrite heart".

Now, Let me come to your question, "Is it a sin if a person who practises vegetarianism, still knows how non-vegetarian food tastes like?" Having seen what Swamiji Maharaj has said about "sins", we can say that to "still know" how a non-vegetarian 'food' (which should logically be called 'carcass') tastes, is not a sin --- but  to cherish the desire to taste meat is, quite rightly, a sin. To know what it was like to be a murderer is not the same as wanting to be a murderer: the first is not a sin but the second is. A short answer to your question is, "no, it is not a sin."