Gentile worshipers would offer grain, fish, fowl, or meat to their gods. The priest would burn a portion of it on the altar. Paul is speaking of the portion the priest would give back for the worshiper to eat or sell in the market. Paul reminds the believers that though idols have no power, believers must be careful not to affect the weaker believers who might think that the believers care about idols if the believers eat food that was sacrificed to idols. He tells believers to be careful with the freedom that they have in Christ.