It's not that hard to spend close to US$500 per person for dinner in a top gourmet sushi or steak place in Japan (or traditional multicourse seasonal dinner in Kyoto) and US$100 for a normal sit down restaurant with wine (fish, tempura, etc.).....or you can spend less than US$10 for a very simple meal such as noodles or street food. US chain fast food tends to cost more than the same items in the USA IME. It's such a wide range that I would argue that you can spend almost whatever you want on food in Tokyo/Japan.