Adam Levine dropped by "The Howard Stern Show" this week, along with his girlfriend Anne V., and found himself discussing a pretty touchy subject: Christina Aguilera's weight. "This is a sensitive subject for women, but why do you think she's gotten so heavy?" Stern asked Levine. "Is she upset?... She used to be so fing hot... And her clothes are too tight, right?" Levine, clearly uncomfortable with where the conversation was headed, chose his words carefully when responding about his fellow coach on "The Voice.