Food is a metaphor for money. After one eats food, the food is no longer there and there is nothing to eat. The money that the brother had received was no longer there and there was no more to spend. Alternate translation: "wasted all your wealth" or "thrown away all your money" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Possible meanings are 1) he assumed this is how his brother spent the money or 2) he speaks of prostitutes to exaggerate the sinfulness of his brother's actions in the "country far away" ([Luke 15:13](./13.md)). (See: [[rc://en/ta/man/translate/figs-hyperbole]])
A calf is a young cow. People would give one of their calves special food so that it would grow well, and then when they wanted to have a special feast, they would eat that calf. See how you translated this phrase in [Luke 15:23](./23.md). Alternate translation: "the best calf" or "the young animal we have been making fat" (See: [[rc://en/ta/man/translate/figs-explicit]])