Hebrews 13:9 (NKJV)
9 Do not be carried about with various and strange doctrines. For it is good that the heart be established by grace, not with foods which have not profited those who have been occupied with them.
Sometimes you just run across verses you think you've never read before. In my NT readings this morning I ran across this verse and thought about all the weird diet fads that people are into these days. Nothing wrong with a diet or eating "right" (whatever that means). But here is the answer for what makes the heart healthy: Grace. Foods do not profit those who have been occupied with them.
Occupied, in the Greek, is parapateo, and means "to regulate one's life" or "to conduct oneself." That's it. Don't regulate your life or conduct yourself with foods. Regulate your life and conduct yourself, busy yourself, with grace.