As Americans, we do seem a little bit obsessed about our diets. While I do not eat kale - ever - I do try to consider the things that I eat, because even though I do like good food, I want to be healthy and feel good. Eating my favorite chocolate chips cookies are great - but I can certainly get carried away, and too much of a good thing can be a bad thing. What we more seldom consider is our spiritual, emotional, and intellectual diet. These are things that we put into our hearts, and Jesus says they are far more important.
Our hearts can be a great source of compassion, empathy, and comfort to others, and it can be a selfish, foolish force for self-righteousness, jealousy and anger that will poison our lives. People who do not keep a close eye on their hearts are not far from disaster in their lives.