[mnehring]

Interesting because when I click on it it says it is esthio. ἐσθίω

[joebuck]

I think I've figured it out. Phago is the aorist tense of esthio. The Strongs number is 5315. To wideawake's credit, this is the tense Zodhiates in his "Complete Word Study dictionary" says is being used in John 6:53 despite the fact the esthio is what appears in both UBS and NA27. BUT, Zodhiates defines the word, as used here, as:

(III) Spiritually to feed by faith and be sustained in a spiritual and eternal life (John 6:50, 51, 53). Zodhiates, S. (2000, c1992, c1993). The complete word study dictionary : New Testament (electronic ed.) (G5315).

[Petrosius]

εἶπεν οὖν αὐτοῖς ὁ Ἰησοῦς, Ἀμὴν, ἀμὴν λέγω ὑμῖν, ἐὰν μὴ φάγητε τὴν σάρκα τοῦ υἱοῦ τοῦ ἀνθρώπου καὶ πίητε αὐτοῦ τὸ αἶμα, ούκ ἔχετε ζωμὴν ἐν ἑαυτοῖς.