There are 2 parts to your statement:
1. People say,: "You are what you eat", meaning that if you eat a lot of fatty food then you may get fat or if you eat low fat foods you are probably slim.
2. People tend to think of nations in culinary terms. True. Pasta is associated with Italy, curry with India and so on.
However, you will find that in most countries you can get any type of food because of the multicultural population.