Difficult question as to a degree fast food and take-away are both the same.
Both have a certain amount of prep to enable them to be made in a time that would suit the customer. I would hate to have to wait for the full cooking time of an Indian dish for example.
Both for me have their place and a place that suits time of day, location and what would satisfy me.
Both are different, takeaway means prepared food that is intended to be eaten off of the premises. Whereas fast food is usually higher in fat, calories, cholesterol, and sodium in comparison to homemade meals that carries the connotation of a standardized product from a globalized chain or franchise, take-away outlets are often small businesses serving traditional food, which is sometimes but by no means always of high quality.