this will show you a graphical interface to setup

$ sudo dpkg-reconfigure tzdata

choose US->Central

Current default time zone: 'US/Central'
Local time is now:      Thu Jan 14 13:27:49 CST 2016.
Universal Time is now:  Thu Jan 14 19:27:49 UTC 2016.

$ date

Thu Jan 14 13:27:57 CST 2016

to list all timezones

$ timedatectl list-timezones

or you can change the timezone with timedatectl, for EST

$ sudo timedatectl set-timezone EST

for central time

$ sudo timedatectl set-timezone America/Chicago