Munching their way through a whopping 29 tonnes of bananas, 13 tonnes of carrots and 38,000 eggs every year – to name just a few items from the annual shopping list – the animals are tricked into exercising their minds and bodies while filling up on calories.
The gorillas enjoy a cooling treat in the summer sunshine with homemade fresh fruit ice-lollies.
And the apes quickly set about melting the ice to reach the fruit - rubbing, biting and standing on it.
Zookeeper Daniel Simmonds told express.co.uk: "The gorillas are impatient – this morning they have been karate chopping and kung fu kicking the ice."
The greedy gorillas also get a work out when handfuls of popcorn are scattered around their enclosure. It takes them so much time and effort to gather up the corn that it stops them piling on the pounds.
The gorillas are impatient – this morning they have been karate chopping and kung fu kicking the ice.
The keepers employ all sorts of ingenious methods to make the animals forage for food like they would in the wild.
Meals are hidden away or put in hard-to-reach places.
Curator of Mammals Malcolm Fitzpatrick told us: "We put the tigers’ meat up on the end of a long pole which forces them to use a burst of activity like they would in the wild."
But sometimes the cheekier animals try to avoid the work.
A particular female sloth bear earned herself a reputation for getting her brother to do all the hard work cracking coconuts.
The sloth would rush in and grab a piece just as the coconut was shattered into pieces.
So maybe there’s one animal who is getting her food handed to her on a plate.