The disciples could no longer disbelieve because of lack of evidence. However, they still had trouble accepting Jesus" resurrection because it seemed too good to be true. Luke"s joy motif surfaces again here. Jesus gave them further proof by eating a piece of cooked fish that was convenient. We should not extrapolate from this that His resurrection body depended on physical food for nourishment (cf. Genesis 18:8; Genesis 19:3). Jesus" resurrection body was immortal ( 1 Corinthians 15:35-49). [source][source][source]
Luke omitted Mark"s reference to Jesus upbraiding the disciples on this occasion for their unbelief ( Mark 16:14). This is typical of Luke who usually did not discourage his disciple readers with references to Jesus criticizing His followers. [source][source][source]