说 “Rice is a staple in China” 会更贴切~ 因为traditional food是指一道菜/菜肴，比如说火锅，北京烤鸭，小笼包等等。但你想表达的意思应该是中国人每顿饭都少不了米饭吧？：）So in this case, saying “In China, among all the traditional food, we eat rice most.” will cost some confusion to the listener (虽然语句上没什么大问题 但是听者可能理会不到你想要表达的意思～）

Yes. Definitely understandable. Personally, I would have written: Out of all the traditional food in China, we eat rice the most.

Hey! Almost! The best way to say it would be: In China, among all the traditional food, we mostly eat rice.