In today’s Gospel from the Mass (John 6:44-51), Jesus is absolutely clear about the necessity of the Eucharist. 

[44] No one can come to me unless the Father who sent me draws him; and I will raise him up at the last day. [45] It is written in the prophets, `And they shall all be taught by God.’ Every one who has heard and learned from the Father comes to me. [46] Not that any one has seen the Father except him who is from God; he has seen the Father. [47] Truly, truly, I say to you, he who believes has eternal life. [48] I am the bread of life.  [49] Your fathers ate the manna in the wilderness, and they died.  [50] This is the bread which comes down from heaven, that a man may eat of it and not die.  [51] I am the living bread which came down from heaven; if any one eats of this bread, he will live for ever; and the bread which I shall give for the life of the world is my flesh.”

Jesus makes an incredible statement that is a preview of His full teaching about Eucharist at the Last Supper:

Jesus is very clear, and very repetitive about the He really is the Bread of Life and people must eat His Flesh if they wish to have eternal life.

The Eucharist is the actual Body of Christ, given up for you.  This is what the Apostles believed, the Church has always taught and what millions of people have been saved by throughout the Age of the Church.

Believe it, or not.