I like to affirm unknown's statement, "Let me start by saying The Old Testament MUST be understood in the Light of the New Testament.".

Leviticus is a book of types, a book of typology. In simple term, spiritual and divine things are portrayed or conveyed using signs, characters, things etc in the Old Testament. So, if you are in the Old Testament age, as a Israelites, you don't consume living creatures that are not clean with respect to diet.  The diet determines the holy living of the priests and the Israelites in the Old Testament.

But, the Israelites is a type of the New Testament believers in reality. We are the "TRUE ISRAELITES" in spirit as Paul shared in his Epistles.

Then, what does it mean in our experience in the New Testament?

A. To Contact the Things outside of Us That Could Affect Us Inside

To eat is to contact the things outside of us that could affect us inside. This especially refers to our contacting of people. When we eat we contact something that is outside of us, something that has nothing to do with us. However, if we eat that thing, it can affect us inside. In Leviticus 11 the things we eat signify people, and eating signifies our contacting of people.

B. To Receive Things from the Outside That Can Be Digested Inside to Become Our Constituent Expressed in Our Living

To eat is not merely to contact something but also to receive something into us. Once a thing is received into us, that thing can be digested inside to become our constituent, that is, our being, our constitution. We all are a constitution of the food we eat and digest. Eventually, what we digest becomes us; it becomes our very constitution. This indicates that contacting people is an important matter. If we intend to live a holy life as required by the holy God, we need to be careful about our contact with people. Our contact with certain kinds of people can cause us to be reconstituted and thus make us another kind of person. Whatever we contact we will receive, and whatever we receive will reconstitute us, making us a different kind of person from what we are now.

For example,

Beasts that do not divide the hoof and beasts that go on their paws (vv. 4-8a, 26a, 27a) signify persons who do not have discernment in their activities and persons who walk and move without discernment. Beasts that divide the hoof and chew the cud (vv. 2-3) signify persons who have discernment in their activities and who receive the word of God with much reconsideration.

Aquatic animals that do not have fins and scales (vv. 10-12) signify persons who cannot move and act freely in the world and at the same time resist its influence. Such people do not have the strength to resist the influence of the sinful world. Aquatic animals having fins and scales (v. 9) signify persons who can move and act freely in the world and at the same time resist its influence. In the Bible, the sea signifies the fallen, corrupted world. The whole world today is a vast sea, and many of those living in this sea do not have fins or scales. They cannot move freely in the world and at the same time resist its influence. As believers in Christ, we should have fins and scales and therefore be able to act freely in the sea of the world without being salted by it.

Birds that eat flesh and carcasses as their food supply (vv. 13-19) signify persons who live in contact with death. In their eating they contact death. The more we contact those who, spiritually speaking, are full of death, the more we shall be defiled by death. If we contact such a person, we shall be filled with spiritual death. Birds that have wings for flying and that eat seeds of life as the food supply (cf. vv. 13-19) signify persons who can live and move in a life that is away from and above the world and who take things of life as their supply of life. Because clean birds have wings for flying, they are able to fly away from and above the world.

So, it is not an outward practice to eat pork or not, but rather WHO ARE YOU CONTACTING in your living as a Christian that matters and what kind of person you are within