Eric and Natalie have been friends since the third grade. Natalie often discusses her struggle to meet her parents' high expectations. Now in high school, she often comments that she is not a good ballet dancer because she is too short and fat. Eric is concerned that she no longer goes out with their group of friends, he rarely sees her anymore, as she practices ballet for hours on end, and she appears to have lost significant weight over the past six months. When they do manage to spend time together, Natalie refuses to eat anything. Eric is worried that Natalie has an eating disorder and needs help. Which warning signs cause Eric to believe Natalie needs help for an eating disorder? Check all that apply.