How do you get a fast metabolism?
Exercise and activity. Your metabolism rate is directly linked to how active you are. Your metabolic rate is how rapidly and efficiently you pull and use energy obtained by foods. People who are active throughout the day have higher metabolisms than those who are sedentiary. To learn about the foods that speed metabolism, see the related page link, further down this page, listed under "Related Questions."
It means that your body digest food very quickly. Example, you eat a really big dinner then two hours later you feel hungry again that means you have a fast metabolism. It also means that you can eat lots and lost of food without putting on any weight whatsoever, I know this because I have a fast metabolism