Anyway of stopping music backing up to my PC when I sync music from my ipod?

I want to put a track from my PC on to my iPod touch 5G but when I try and sync a playlist from iTunes on my PC to my iPod touch it starts backing up every single bit of music from my iPod touch to my PC. Is there any way of stopping all the music backing up to my PC while it just syncing the playlist with the tracks I want onto the ipod?