Physically, it means taking Holy Communion. Spiritually, it means reading Bible - God's Word (bread of life) and conscious awareness of Christ's work at the cross (blood covenant). Reading and meditating on God's word as directing by Holy Spirit would feed one's spiritually and the person is growing from it just as one grow physically by taking in physical food. Whereas through Christ's work at the Cross, believer are declared righteous and no more under condemnation in other word. The constant awareness of righteousness is very important to one spiritually.. emotionally and hence physically..