Do I have a FASTER metabolism?

i used to eat nothing but junk food all day, i mean all day every 30 mins i would have pizza or a bowl of cereal, or oatmeal pies, twinkies that stuff ALL day. i eventually became overweight 215 pounds at 5'10 i now eat Extremely healthy only 6 meals a day all of which are only protein and veggies and dairy with only one cup of oatbran in the morning for breakfast i now weigh 157 pounds and am 6 feet tall is it possible because i used to eat soo much and the food that i eat that i have a super fast metabolism? The only thing I drink now is water and green tea