While Jesus was at the well in Samaria speaking to the woman, his disciples urged him to eat (John 4). Craig Keener’s comments here are helpful.
“This picture does not deny the Johannine Jesus’ full humanity. Jesus here does not strictly refuse physical food, and an ancient audience, aware of the demands of hospitality, would recognize that Jesus ends up with not only lodging but physical food (4.40). The issue is not docetism (cf. 1.14), but priorities; his mission takes precedence over his comfort, foreshadowing his thirst at the cross (19.28).”
“Jesus’ mission involved not just one meal, but an entire harvest of spiritual food that was on the way (4.34-38). In context, the narrative probably contrasts Jesus’ commitment with that of the disciples. The disciples had gone into a Samaritan town with apparently little effect on the populace; Jesus had ministered to one woman and brought the entire town to himself.”
Keener is right-on; he nicely draws out John’s repeated emphasis on Jesus’ mission/task as well as the apostle’s use of metaphor and irony.
See Craig S. Keener, The Gospel of John: A CommentaryVol 1 (Peabody: Hendrickson, 2003), 623-4. Note: Above emphasis mine.