Our Lord said “I have come that they may have life, and have it more abundantly.” (Jn 10.10) When being tempted by the devil, he quoted the verse “Man does not live on bread alone, but on every word that comes from the mouth of God.” (Matt 4.4) Jesus Christ is Himself the Word made flesh and we are made to live on Him. As St Paul said to the Athenians at the Areopagus “In Him we live and move and have our being.” (Acts 17.28)
The manner in which we would live in and through Christ was given to us by Christ Himself in the Blessed Eucharist. He taught the people: “As the living Father sent me, and I live by the Father; so he that eats me, the same also shall live by me.” (Jn 6.58) This was the plan of God from the beginning, that He would give us Himself to be the food and life of our souls.
When we receive Holy Communion with the right dispositions, we are being nourished in the way that God chose to provide for us. This is what gives us “life more abundant” according to the desire and love of Christ for us.