The words φαγεῖν and τρὠγω are translated to eat,' but the occurrence of both words in John 6 shows a difference in their signification.
Φαγεῖν is used in verse 53 and in that part of verse 58 where it says "not as the fathers ate and died." It refers to eating for the sake of present hunger. The Lord says in verse 53, ἐὰν μὴ φάγητε, &c.: their case would be hopeless unless they ate the flesh and drank the blood of the Son of Man.
τρώγω occurs in verses 54, 56, 57, and in the latter part of 58 ("he that eateth this bread shall live forever"): it may imply the leisurely and habitual enjoyment of what is eaten. It is applied generally to the grazing of cattle (ruminating), and in the case of human beings supposes a slower process of mastication than merely ‘eating.' This would have a peculiar force in these verses where the figure is not merely (as in verses 49 and 58) that of taking food to keep oneself alive, but the more quiet appreciation and feeding upon what is within reach. Christ is the food. ἐσθἰω, ‘to eat,' is often used in the general sense of taking food. βιβρώσκω ‘to eat,' occurs but in one place, John 6:1313Therefore they gathered them together, and filled twelve baskets with the fragments of the five barley loaves, which remained over and above unto them that had eaten. (John 6:13).