Catholic Fundamentalism believes that Jesus’ words: “If you do not eat My Body and drink My Blood, you do not have life in you.” are among the most important thing He said.
The people to whom He was speaking were alive. So, He must have had a different meaning of “life”. Catholic Fundamentalism believes that He was speaking of the life we have that is closer to God. If we eat His Body and drink His Blood, we are closer to Him. His Body and Blood brings life to the dead places in our brains.
What does that do for us? His Body and Blood “turns on” dead places in the brain. They may be brain cells that are brought to life. There are connections that can, by the power of His Body and Blood, have current flow through them. We may think of what His Body and Blood do as bringing life to otherwise dead areas of the brain.