Venerable Fulton Sheen
“In the natural order, a living thing assimilates its food and incorporates it into its own substance. In the Eucharist, the roles are reversed. The Eucharist is food for our soul, but the power of assimilation here belongs to Christ, and it is He Who, feeding us, unites us and incorporates us with His life. It is not Christ Who is changed into us, as is the food we eat; it is we who are incorporated in Him.”
Source: Ven. Fulton Sheen, These are the Sacraments