The BeNei Yissasschar [Adar, 2:7] explains that all matter exists with HKBH's energy. Gd is invisible but everywhere, the dark matter and the dark energy of this universe, if you wish. Our purpose in this world is to utilise this energy, to elevate it.
Some foods are Assur; Assur means tied, restricted, unavailable for us to utilise. Other foods are Muttar; Muttar means untied, free, accessible for us to utilise and elevate.
There are situations in which the Assur is corrected and becomes Muttar, the prohibited is corrected to become accessible. Taking tithes from grains, fruit, dough, fleece, animals and meat makes them accessible as does slaughtering.
There are also situations in which the prohibition becomes