If you eating fast food, of course it is going to make you fat because most the fast foods made from flour, milk, butter, cheese and oil. Next, it will affect to your body and if you have too much weight it will make to obesity and if you are obesity it will affects the body such as the effect on the movement of the body, the circulatory system and respiratory system, etc. Then, fast food is the main reasons that cause obesity if you eating too much but if you eating too much. In contrast, you should turn to eating healthy food such as vegetable and fruit it will make to you good health and is good for your body.