Korean grammar question: What is the difference between 'food to eat' and 'food that one is good at'?

Hello, I am a foreigner studying Korean. I came across the sentence "그 식당의 잘하는 음식을 알려 주고, 먹을 음식을 정해 보세요." in the Ewha Korean textbook, and I have a few questions. First, I noticed the expression '먹을 음식' here, and I'm curious why it is used instead of '먹은 음식.' Is the expression '먹을 음식' more natural? Also, the expression '잘하는 음식' stands out to me. Is there a reason for saying '잘하는 음식' instead of '좋은 음식'? Is '잘하는 음식' a phrase that locals use more frequently? I would appreciate any help you could provide to clarify these points!