Theophylact of Ohrid

When the disciples still did not believe and were not convinced even by touch, the Lord added yet another proof — the partaking of food, consuming what was eaten by a certain divine power. For everything that is naturally eaten by the mouth passes out through the bowels, but He, as we have said, partakes not according to the law of nature, but by a special dispensation.

Commentary on Luke ↗

Gregory the Dialogist

To establish the truth of the Lord's resurrection, we should also note what Luke reports, saying: "Eating together with them, he commanded them not to depart from Jerusalem." And a little later: "While they were watching, he was lifted up, and a cloud received him from their sight." Note the words, mark the mysteries. Eating together he was lifted up. He ate, and he ascended, so that through the act of eating the truth of his flesh might be made evident.

Forty Gospel Homilies, Homily 29 ↗

Bede

To convey therefore the truth of His resurrection, He condescends not only to be touched by His disciples, but to eat with them, that they might not suspect that His appearance was not actual, but only imaginary. Hence it follows, And when he had eaten before them, he took the remnant, and gave to them. He ate indeed by His power, not from necessity. The thirsty earth absorbs water in one way, the burning sun in another way, the one from want, the other from power.

Catena Aurea by Aquinas ↗