iphone show 1G memory occupied

Hi

After I change my itune new version 5.0.1 and I found my iphone4 will show more momory occupied about 3~4G by yellow color show in itune. Would you please advise me how to delete them or it relatived with i-cloud operation we can't be delete. Even I update every data in my iphone but the yellow occupied still exist).

You help will be much apprecated.

Regards,

Benjamin Wu