1. Demi Lovato is one of the sincerest celebrities today. The 23 years old singer and actress often opens up about the demons in her past: Demi struggled with bi-polar disorder and bulimia. She said that bulimia was an addiction and it took over her thoughts completely. It wasn’t easy for Demi to get rid of those troubled demons, but with enough support and love from her family, she successfully overcame her problems, including bulimia.