When people talk about fast food they usually think about McDonald's or similar restaurants, but Japanese have also their own version of fast food that is actually older than the western one. They have tempura, ramen, udon and many other food that can be fast coked. People usually, workers go there and take a healthy food based on vegetables, fish and meat. Fast food in Japan doesn't have the image of bad or not healthy. Actually I love to eat in those places. Just be ready to eat fast!! :)