I have heard over and over how jennifer aniston followed the zone diet
to lose weight. I would like to know what workout she does to keep her
body so toned. Does she lift weights, do yoga, run? How many days does
she work out? Is her workout  different now then what was it when she
lost the original weight and what workout does she do now to keep it
off?

"Jennifer Aniston's use of the Zone Diet program is discussed in some
of her interviews. In addition to information on her following of the
diet program, there?s info on what exercise programs she does and
other related tips and information you might find useful."

http://www.dietsguide.com/jennifer-aniston-zone-diet.html

She has said in numerous interviews that she does PILATES.  
And she also worked with (I don't know if she still does)
personal trainer to the stars, Kathy Kaehler.