Jesus changed the law! Actually, he did not.

Early Christians wanted to appeal to gentiles, so made up ways whereby they could just ignore the rules of the OT. In effect they were selling Judaism Lite - all the history of Judaism, but no need to be circumscribed!

Modern Christians want to be able to tuck in to lobster and pork, so maintain this pretence that Jesus changed the laws of the OT.

The truth is that he never did, and indeed was quite clear on that.

Mat 5:17 “Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them. 18 For truly I tell you, until heaven and earth disappear, not the smallest letter, not the least stroke of a pen, will by any means disappear from the Law until everything is accomplished. 19 Therefore anyone who sets aside one of the least of these commands and teaches others accordingly will be called least in the kingdom of heaven, but whoever practices and teaches these commands will be called great in the kingdom of heaven. 20 For I tell you that unless your righteousness surpasses that of the Pharisees and the teachers of the law, you will certainly not enter the kingdom of heaven.

Have all things been accomplished? There are still wars, still people dying of hunger and thirst, still evil in the world. Clearly not all has been accomplished, so the law is unchanged.

It is as simple as that.

Yes, but I really want to eat lobster!

Christians have worked out all sorts of ways to try to get around this. 

Jesus fulfilled the law so it no longer applies

A classic tactic is to pretend Jesus fulfilled the laws by perfectly obeying them, and therefore the laws do not need to be obeyed now... except the ones they want to keep, of course.

This fails on two scores.

Firstly, Jesus fulfilling the Law is about Jesus fulfilling the prophecies in the book known as the Law, it is not about obeying the laws because that is not what fulfill means!

Secondly, it makes no sense to think a set of laws should be abandoned because one person obeyed them perfectly. If something is prohibited, why should it suddenly not be prohibited just because one man managed to avoid doing it his whole life? It makes no sense.

Here are some recent ones given to me on a discussion at CARM.

"But I say unto you."

'but in the Sermon on the Mount He itemized many things in the law which He overrode with His many "But I say unto you." '

The reality is that none of those are Jesus saying that actually you can do something prohibited in the OT; none of them are Jesus making the laws more relaxed or obsolete. They are Jesus making the laws even more prohibitive.

Mat 5:21 “You have heard that it was said to the people long ago, ‘You shall not murder, and anyone who murders will be subject to judgment.’ 22 But I tell you that anyone who is angry with a brother or sister will be subject to judgment. Again, anyone who says to a brother or sister, ‘Raca,’ is answerable to the court. And anyone who says, ‘You fool!’ will be in danger of the fire of hell.

...

27 “You have heard that it was said, ‘You shall not commit adultery.’ 28 But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart. 

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31 “It has been said, ‘Anyone who divorces his wife must give her a certificate of divorce.’ 32 But I tell you that anyone who divorces his wife, except for sexual immorality, makes her the victim of adultery, and anyone who marries a divorced woman commits adultery.

Jesus on the Sabbath

'And did you forget about how He overrode the "no work on the Sabbath" law by allowing His disciples to pick grain on the Sabbath?

The truth is that Jesus said that what he did on the Sabbath was lawful because of what David had done generations earlier.

Mark 2:23 One Sabbath Jesus was going through the grainfields, and as his disciples walked along, they began to pick some heads of grain. 24 The Pharisees said to him, “Look, why are they doing what is unlawful on the Sabbath?”

25 He answered, “Have you never read what David did when he and his companions were hungry and in need? 26 In the days of Abiathar the high priest, he entered the house of God and ate the consecrated bread, which is lawful only for priests to eat. And he also gave some to his companions.”

27 Then he said to them, “The Sabbath was made for man, not man for the Sabbath. 28 So the Son of Man is Lord even of the Sabbath.”

Jesus did not change anything, he pointed out the Pharisees' interpretation was - and had always been - wrong.

Jesus said it doesn't matter what one eats

'Jesus said it doesnt matter what one eats but He affirmed that God created man and woman in His image and it was for this reason they shall be united.'

Quote-mining Jesus! If you actually read Mark 7, Jesus was taking about washing your hands before eating. This was a tradition of the Pharisees, not a Bible requirement.

7 The Pharisees and some of the teachers of the law who had come from Jerusalem gathered around Jesus 2 and saw some of his disciples eating food with hands that were defiled, that is, unwashed. 3 (The Pharisees and all the Jews do not eat unless they give their hands a ceremonial washing, holding to the tradition of the elders. 4 When they come from the marketplace they do not eat unless they wash. And they observe many other traditions, such as the washing of cups, pitchers and kettles.)

5 So the Pharisees and teachers of the law asked Jesus, “Why don’t your disciples live according to the tradition of the elders instead of eating their food with defiled hands?”

...

9 And he continued, “You have a fine way of setting aside the commands of God in order to observe your own traditions! ...

14 Again Jesus called the crowd to him and said, “Listen to me, everyone, and understand this. 15 Nothing outside a person can defile them by going into them. Rather, it is what comes out of a person that defiles them.”

Christians can certainly use this to justify not washing their hands before eating (but I advise against it; this one actually makes sense), but it has nothing to do with dietary restrictions.