'Gunnar Peterson says the Kardashian is an \'animal\' in the gym, and also works out with the whole Kardashian family! ET gets the secrets!' 

Tags: fitness , News , Khloe Kardashian , Kris Jenner , kim kardashian , kourtney kardashian , 2015 , TV , Entertainment Tonight , etonline , et online , et , Gunnar Peterson , Kellen Lutz

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