The Corinthians were free to eat meat offered to idols from the market (as long as nobody made a big deal about it), but not to eat in the idol's temple — same meat, but the setting made a difference. (redeeminggod.com)
With respect to the food laws, for instance, Paul upheld private conscience as the legitimate determiner of right and wrong, so that two different people could eat the same meat, and for one it would be a sin yet for the other it would not (Rom. (religion-online.org)