What are the determinants of a fast metabolism?

genetics, exercise, eating patterns/ what you eat are some factors in metabolism. if you have parents with naturally fast metabolisms you will too. if you exercise frequently your metabolism will be fast because it constantly needs energy to be able to perform. if you eat little amounts, but often, and good nutritional foods, this will also raise your metabolism because your body is continuously burning something at a steady pace and it knows it will be fed again soon so its comfortable with burning the food