Assuming by Epiousios you’re meaning “for the approaching day”, that would not make any sense. He was speaking in the past tense. “Though I’ve been speaking figureatively, a time is coming when I will no longer use this kind of language but will tell you plainly about my Father”.
I am referring to Epiousios as the supersubstantial bread, the Eucharist. This word is used nowhere else in Scripture, except by Jesus. This usage was prevalent ("ho artos hÄ“mÅn ho epiousios") with the early Christians even before the Gospels were written. St. Jerome, no stranger to Greek translated it as supersubstantial bread indicating the Holy Nature of the bread.
To suggest otherwise implies that the writers of the Gospels engaged in a false “theologizing” of a word intended only to convey a straightforward earthly sense.