If a Christian has been told that the meat that is served is sacrificial meat, and he still goes on to eat it, he will be denounced
by his pagan companions. Perhaps Paul means that pagans will mistake the Christian’s act of eating for an act of worshipping the idol. Or perhaps the pagan will be indignant when he sees that sacrificial meat is eaten by someone who does not honour the gods.
Paul assumes that the believer will give thanks to God for the food before him. If the believer then eats meat that he has been told is sacrificial meat, he will be denounced
for something for which he has thanked God. This will lead to God’s name being dishonoured (compare 1 Corinthians 10:31).
30 If I partake with thankfulness, why am I denounced because of that for which I give thanks?