Which health-related activity could be effectively completed using only internet sources

Why is it that people at first would be nice then they shut you down? (school matter)

Ihave a really high metabolism and only weigh 70 pounds (13 almost 14). people always ask me two questions: do you ever eat and how do you eat so much and stay so skinny.i am worried that a high metabolism wont me forever. what are some safe steps i can take to maintain being fit. (also, i already work out i am a dancer so i get cardio a lot)

Can someone give me one specific health problem (within unhealthy eating) and explain it. !