While the book is pretty anti-Catholic at times (sometimes ignorantly so), Ivan Richards in To Find the Path to Eternal Life, when commenting on John 6:50-60, 66, affirmed John 6 is, in part, touching upon Eucharistic theology:
Comment: Jesus
was speaking of his atonement and the sacrament of which we would be commanded
to partake, but when the people heard Jesus speak, they took him literally,
thinking in their minds that he was a lunatic to say such things. The way Jesus
expressed things was too difficult for them to understand. He always spoke in
parables to them. Very few people asked him what the parables meant. (Ivan Kent
Richards, To Find the Path to Eternal Life Ye Must First Seek to Obtain My
Word [Xlibris, 2019], 43)