Then Jesus called to the crowd to come and hear. “Listen,” he said, “and try to understand. It’s not what goes into your mouth that defiles you; you are defiled by the words that come out of your mouth.” Mt. 15:10-11
Here Jesus is addressing the stress the Pharisees placed on dietary laws, as though adherence to those laws made them superior in God's sight. Jesus' reply, of course, is that holiness isn't achieved that way. The foods we eat are inconsequential to God in the sense that in themselves they are not capable of destroying human relationships. However, our words and actions are potent builders or destroyers of relationships.
It is impressive how backwards we can get things. How we emphasize correct nutrition, and dieting is big business. While not necessarily wrong, we often make them the priorities, while we underemphasize the need to curb out tongues. We swear and cheat freely, as though they don't matter. Jesus would say, even today, that we can get as backwards as the Pharisees.