Why can i consume such large amounts of chocolate?

Ok so i'm 15 male 5'9 135 lbs (i know i'm on the skinny side) and i can eat CRAZY amounts of chocolate. Like if you've ever seen the chocolate nuggets by hershey? i can literally eat two bags of those in an hour, with absolutely no side effects. no headaches, not jittery, no crashing, no stomach aches nothing. But when my friends family, or anyone else i know big or small try to eat the amount i eat they get sick and stuff. What is it about me that allows me to do that?