Don't be ridiculous.
This is a metaphorical statement.
Here "life" refers to the re-establishment of our loving service relationship with God. This relationship brings a person complete fulfillment. Jesus uses this metaphor elsewhere:
“My food,” said Jesus, “is to do the will of Him who sent me and to finish His work." (John 4:34)Doing the will of the Supreme Being means serving the Supreme Being. Thus the analogy of re-establishing our loving service relationship with God with food and becoming fulfilled can be made. Once we are "eating" of our loving relationship with God, we become fulfilled, and never hungry or thirsty.
Meaning of 'bread of life'
Furthermore, the metaphor, "bread of life" also indicates that Jesus is acting as a means of delivering life. Bread can be seen as a means or vehicle because it is a means to nourish the body. But instead of nourishing the body, Jesus is speaking of nourishing the spirit-person within, who is spiritual.
Yes, each of us is looking for fulfillment, and this is why we chase after the goodies of the physical world. This is why we seek success, wealth, sensual pleasures, family relationships and friendships. We are each looking to become fulfilled from the forms and things of the physical world. Unfortunately, these forms and things of the physical world do not satisfy us because we are not these physical bodies.
We are not physical by nature. We are spiritual. We are simply occupying these physical bodies much as a person drives a car. Thus in order for us to become fulfilled, we must satisfy our spiritual selves.
To attempt to be satisfied by filling up the physical body would thus be compared to a hungry person driving a car to think that if he fills up his gas tank with gas he will no longer be hungry.
Because Jesus was surrendered to the Supreme Being and was God's loving servant, He was God's vehicle, as he did God's will. As Jesus confirms with his statement above: The actual delivery or ‘saving’ of others is performed by God, but through the vehicle of His loving servant.
Seen but do not believe?
So why is Jesus saying to the audience that they have seen Jesus but do not believe?
Jesus is not speaking of believing in his existence. Accepting Jesus' existence was no big deal because Jesus was standing before them.
Rather, the word "believe" here is being translated from the Greek word πιστεύω (pisteuō), which actually means, according to the lexicon, to trust - have confidence in or to entrust.
Jesus is speaking of their trusting him. Why?
Because trusting him means to have confidence in his teachings. It means following his teachings and having faith that following those teachings will bring them happiness and fulfillment.
Thus to "trust" in the loving servant and representative of God who is doing God's will is to "trust" in the Supreme Being. It means to take shelter in the Supreme Being. It means to surrender our lives to our dearmost friend and companion, the Supreme Being, and trusting Jesus as we attempt to follow his first and foremost instruction:
" 'Love the Lord your God with all your heart and with all your soul and with all your mind.' This is the first and greatest commandment." (Matt. 22:37-38)