Do not make yourselves abominable through any of the crawling things. Do not contaminate yourselves to them lest you become contaminated by them.
Be’er Mayim Chaim: Abominable…contaminate yourselves…become contaminated by. Had the Torah simply stated, “Don’t eat them” we would still look for a hechsher on the wrapper. This more elaborate warning about forbidden food clues us in on the way those food items affect our neshamos.
Man is called  olam katan /microcosm because he includes all the worlds, spiritual and physical. As the Ari z”l taught, Hashem took counsel with His cabinet of advisors – from both the spiritual and physical worlds – so that all of them would willingly contribute something of themselves to Man’s creation. The four levels of Man’s neshamah – nefesh, ruach, neshamah, and neshamah d’neshamah – are linked to the four spiritual worlds of atzilus, beriah, yetzirah, and asiyah. All the foundational elements of the physical world contributed to his creation. His very composition is in the image of Yaakov’s ladder – planted firmly on the ground, but reaching to and touching the heavens.
Because both universes are invested in him and are joined in him, Man’s actions affect them. When he accomplishes anything of significance through his actions in the physical world – especially davening and learning – he can elevate it and join it to the spiritual worlds, all of which exist within him. There is complete justice in this. Because all parts of the physical world contributed to his creation and continue to nurture him in his activities, they participate vicariously in his achievements. They play a role in his spiritual accomplishments, and are therefore elevated through them.
A chief pathway through which Man elevates the world is that of eating – an activity which, at first inspection, is spiritually fraught. The truly enlightened person will have no interest in any activity sourced in his animal self, and shared completely with the animal kingdom. Indeed, he will be entirely repulsed by it. He will understand that the source of all pleasure is Hashem Himself; any other enjoyment is a poor substitute made odious by the fact that it is motivated and propelled by the part of him that is common to infra-human species.
On the other hand, it is inescapable that HKBH made eating, drinking, etc. necessary and important requirements for the continuity of life, at least to the extent that they are necessary to sustain life. When used in this manner, the nitzotzos of kedushah /Divine sparks of holiness that are resident in all physical things and that empowers their existence are released and elevated.
In its most perfect form, such eating requires the person to understand that the physical enjoyment that accompanies his eating is of less than secondary importance. Intellectually, he rejects all that is purely physical; he is attracted to eating only to the extent that he is able to liberate and elevate the spark of kedushah within the food. He eats only to break his hunger, and sits at a table in the same manner that he approaches any mitzvah. Conscious of his place at Hashem’s table, he sits in reverence, participating in an act of avodas Hashem, discharging his obligation with love and joy.
Not everyone has acquired the spiritual level at which he can completely spurn the physical. (In the intentions that the Ari z”l prescribes for different activities, he explains that the selection that must accompany eating is sourced in Chochmah – which we can understand is not accessible to everyone.) There is a back door route, however, to elevating the sparks. Even should a person eat for more pedestrian reasons than elevating the nitzotzos alone, he still can accomplish the same. He needs to meet two conditions. He has to at least take pains to ensure that he will not consume the slightest amount of impermissible food. Additionally his intention must include spiritual value; his goal must include providing himself with the strength with which to daven and perform mitzvos. When both of these conditions are fulfilled, he will find himself moved sufficiently that, in his newly elevated state, he will long far more for continued closeness to Hashem than for the next tasty morsel. Such feelings take him to a place where he will now reject his previous infatuation with eating primarily for pleasure. With this realization comes a separation of the nitzotzos from what usually houses them. Once separated, they too can be raised up.
On the other hand, the alternative is not pretty. Should his food contain anything forbidden, then not only must he fail to elevate the sparks as he should, but he and the sparks together will fall to an even lesser plane. Besides this, he is guilty of abusing the vast majority of the material that is neither a spark of holiness nor of its opposite. Its function is fulfilled only when the sparks are separated through the proper intention of the one who eats. When this is not done, in effect he has abused and wasted the animal whose life was taken needlessly!
We now understand the three negative references in our pasuk. Three evils are committed by eating what is forbidden: the animal itself is wasted; the eater is contaminated by the spiritual toxicity within it that now clings to him; the spark of kedushah is lost. It is an abomination to eat meat that could have been purged of its unholy nitzotz, and now remains in its unredeemed state. By incorporating the nitzotz ha-ra, you contaminate yourself, and block the effects of your contact with the Shechinah. Beyond all of these, the greatest crime, the greatest contamination you visit upon yourselves, is the lost opportunity to elevate the sparks of kedushah when you had the chance.
 Based on Be’er Mayim Chaim, Vayikra 11:43
 Avos de-Rabbi Noson 31:3