Michael Bird argues the following on the incident at Antioch:
The real problem was not the food but the company it was consumed in. The objection of "those of the circumcision" and "certain men from James" was that these meals made Gentiles equals and not simply guests in the Jewish Christian community! Gentiles did not have to judaize/do works of the law/be circumcized in order to have the membership status and privileges of Jews. Circumcision of Gentiles is what links Gal 2:1-10 and the rest of Galatians with Gal 2:11-14.
Ok, here's some fairly non-systematic thoughts on the matter. As one of Michael's quotes makes clear, there are two major issues which arise in Jewish literature: food and idolatry. So it is at least possible that this pattern continues in earlyies Christianity. Idolatry can be eliminated for obvious reasons but food cannot be eliminated that easily. Moreover, the problem involves something to do with a Jew like Peter not doing 'works of the law' (Gal. 2.15-16) which appears to imply that some kind of law breaking (real or perceived) is going on and that Peter is involved in some way (I am hesitant to say if Peter did eat banned food as there is no explicit evidence - he may not have been able to stomach it for all we know - but the perception is clear). Given the range of Jewish and pagan texts which discuss the issue of food then this seems to me to be a very good contender for the problem. If Peter is associated too strongly with people eating pork or whatever it does (cf. Sanders) discredit his mission to Jews.
As for company, there is a problem with this argument. Paul's mission is recognised in Jerusalem (Gal. 2.9) and combined with this is the lack of any major evidence that Jewish and gentile Christians were not eating with one another or that this was an issue in earliest Christianity. Does this not suggests that there was no problem with the company being kept at Antioch?
And is circumcision an issue here. Again there is no problem in Jerusalem with circumcision. This is why I think food laws are a problem because if Peter is associating too much with lawless gentiles then he is effectively being identified with those kinds of people and this, again, seriously discredits a Jewish mission. Furthermore, is circumcision really included in the term 'Judaise' (cf. Gk Esther 8.17; War 2.454, 462-63; and Dunn's argument)?