"Jesus said to them, 'My food is to do the will of the one who sent me and to do his work.'" (Jn 4:34 NBS)
The first place where God must reign is in us. God's reign must become more important to us than food. As we fast, we say, "Father, what I desire more than food is to do Your will. May my life serve to establish Your reign. I pray that Your kingdom will come; I make myself available for it to happen.
May only that which is of God be present in my life. I fast to set myself apart, consecrate myself, and dedicate my life to God. This fast is an invitation to God to come and reign in me. Less of me and more of Him.