Can Catholics eat food offered to idols? Mathew 15:11


  What goes into the mouth does not make anyone unclean; it is what
  comes out of the mouth that makes someone unclean.


Can Catholics eat food offered to idols?
Probably not (I was going to say no, but it's rather nuanced). 

St. Paul takes up the issue in 1 Cor:8.  The reason isn't so much that he believed in the idols or that the food in-and-of-itself was bad, but because it gave the appearance (aka scandal) of a follower of Christ participating in a pagan ceremony.  The rule at place is much bigger than just eating, it's mainly about not confusing others who may look up to you as a solid Catholic.

And the Bishops in the footnotes of the Bible make the point :


  Although the problem with which he is dealing is dated, the guidelines for moral decisions that he offers are of lasting validity. Essentially Paul urges them to take a communitarian rather than an individualistic view of their Christian freedom. Many decisions that they consider pertinent only to their private relationship with God have, in fact, social consequences. Nor can moral decisions be determined by merely theoretical considerations; they must be based on concrete circumstances, specifically on the value and needs of other individuals and on mutual responsibility within the community.


(which is interesting that they call it dated, since it's your question entirely!)

And St. Paul makes the point again in Romans where he says that if anyone had a problem with the food you eat, to take it seriously.  

And the interpretation from the footnotes says (referencing the passage you cited):


  Since Christ spells termination of the law, which included observance of specific days and festivals as well as dietary instruction, the jettisoning of long-practiced customs was traumatic for many Christians brought up under the Mosaic code. Although Paul acknowledges that in principle no food is a source of moral contamination (Rom 14:14), he recommends that the consciences of Christians who are scrupulous in this regard be respected by other Christians (Rom 14:21). On the other hand, those who have scruples are not to sit in judgment on those who know that the gospel has liberated them from such ordinances


So basically, be sensitive to both the judgement and impressionability of those around you.  Take peoples' opinions seriously and don't do anything that leads another into sin. 



On the other hand, James (The Bishop of Jerusalem, not one of the two from the Gospel) said in Acts:


  It is my judgment, therefore, that we ought to stop troubling the Gentiles who turn to God, but tell them by letter to avoid pollution from idols, unlawful marriage, the meat of strangled animals, and blood. For Moses, for generations now, has had those who proclaim him in every town, as he has been read in the synagogues every sabbath.


And Haydock's commentary says


  In these prohibitions, the Church indulged the particular feelings of the Jews, that the bond of union between them and the Gentiles might be more closely united; the latter in these two instances giving way to the prejudices of the former, who in their turn gave up much, by submitting to the abolition of the ceremonial law of Moses. This prohibition was of course only temporary, and to cease with the reasons, which gave rise to it.


Which is more-or-less in line with what Paul says.  There's no inherent prohibition about eating the food.  Solidarity with other Christians, and the avoidance of scandal is the  main thing. 



I don't know a lot about Hindu culture, but in America we have a tradition of shaping our butter for Easter in the shape of a lamb.  If you gave a butter lamb to a Hindu friend to take into their home, wouldn't their kids find that peculiar?