John Calvin Commentary Acts 27:35

"And when he had said this, and had taken bread, he gave thanks to God in the presence of all; and he brake it, and began to eat." — Acts 27:35 (ASV)

He took bread. To better encourage them by his own example, he takes bread and eats. Luke says that he gave thanks, not only according to his daily custom, but because that greatly served to testify to his boldness and good confidence.

It is not to be doubted that Paul himself did that when he took food, which he commands other men; but now he does not only testify to his thankfulness, nor does he only desire of God that He will sanctify the food which he is about to eat, but he calls upon God without fear, who is the author of his life, so that those poor souls, who were drenched in sorrow, might conceive some good hope.

And he prevailed at least this far: that they gathered enough courage to take food, they who had, through fear, forgotten to care for their lives.