The next five chapters in Leviticus detail what are often referred to as ‘purity laws’, and this particular chapter relates to ‘clean’ and ‘unclean’ animals.  Although the distinctions might be difficult to understand, they certainly do not refer to regrets God had in certain aspects of His creation.  Diet was just going to be one of the many ways that God was going to set apart His people from the general population.  If you’ve ever had a vegetarian or a vegan friend for dinner, then as their host you will completely understand that their lifestyle requires your menu to be different, and to take into consideration their abstentions.  Similarly God wanted His people to be distinguished by what they did and did not eat.  The Israelites needed to resemble God’s holiness and in fact a ‘simple’ diet made this an attainable reality rather than an abstract ideal.  Verse 45 demonstrates that obedience to these purity laws was to be a response to God’s grace.  If they thought for a second ‘why?’, the response “For I am the Lord your God, who brought you up out of the land of Egypt to be your God.  You shall be holy for I am holy” should have been more than a sufficient response!  Of course these laws are obsolete with the life, death and resurrection of the Lord Jesus, who himself tells us that “there is nothing outside a person, that by going into him can defile him, but the things that come out of a person are what defile him”.  Indeed Paul tell us that “whatever you eat or drink, or whatever you do, do it all for the glory of God”.  We are still His distinct people, and we are to be Holy (set apart) as He is Holy, but we accomplish this through our resemblance of Christ, and our response to His grace.