Physical food only sustains our temporary bodies for the few years we live here on earth. It takes spiritual food to give us spiritual strength to "walk in the Spirit" (Galatians 5:16, 25) and to fight spiritual battles with spiritual weapons (2 Corinthians 10:4) against spiritual foes (Ephesians 6:12) as citizens of the spiritual Kingdom of Heaven (John 3:5).
The enemy knows our weaknesses, and we need to be aware of them as well, because that is exactly where he will strike time after time… When we fail to use the armor of God we become ineffective soldiers for God…