Animal nutritionists have cancelled a cliché and issued a banana ban for monkeys at a zoo in Devon.
Experts have likened giving fruit to the primates to humans eating too many fatty foods like cake and chocolate.
Amy Plowman, head of conservation and advocacy at Paignton zoo, said it had not been too hard to wean the monkeys off bananas and give them vegetables instead.
"They didn't get a choice but - unlike children - they couldn't complain."
Dr Plowman said the monkey troop have now been put on a strict diet and have been avoiding food that is too sweet and sugary – and already their fruit-free diet is bringing improvements in physical health and changes in some behaviours.
"Compared to the food they would eat in the wild, bananas are much more energy-dense - they have lots of calories - and contain much more sugar that's bad for their teeth and can lead to diabetes and similar conditions," she said.
The news follows experts issuing a stark warning that Britain's pet monkeys are suffering from an obesity epidemic, caused by their couch potato lifestyle.Suggest a correction