Acts 20:27 (NKJV)
There is a saying about how the food you eat has an effect on your overall well-being, you are what you eat. If you eat healthy foods you will be healthy and if you eat a lot of junk food you will not be so healthy. Concerning natural food, we need to have a diet that is balanced with foods from all of the proper food groups. Spiritually speaking we need to get to know all of what God's Word has to say and not just our favorite parts of the Bible or whatever happens to be the latest emphasis in Christian circles.
Our main source of spiritual food is from the Bible, but we need a proper balance. For example, some people have so much of their focus on judgment and sin. They have a steady spiritual diet of teaching in this area so that is how they view everything. Any little sin they see is magnified in their eyes and worthy of condemnation. Other Christians have a spiritual diet of nothing but the mercy and grace of God and this is all they seem to see. It is almost as though sin does not exist for them and they end up living undisciplined and irresponsible lives. These are just a couple of examples.