Subscribe | UPI Odd Newsletter Subscribe PAIGNTON, England, Jan. 17 (UPI) -- A British zoo said its monkeys have been put on a banana-free diet because the fruits are too sweet and sugary. Officials at the Paignton Zoo Environmental Park in Devon, England, said the facility weaned its monkeys off of fruit and onto a more vegetable-focused diet because it is healthier for the primates. Advertisement "People usually try to improve their diet by eating more fruit -- but fruit cultivated for humans is much higher in sugar and much lower in protein and fiber than most wild fruit because we like our fruit to be so sweet and juicy. Giving this fruit to animals is equivalent to giving them cake and chocolate," said Amy Plowman, the zoo's head of conservation and advocacy. and an expert in animal nutrition. "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. It can also cause gastrointestinal problems as their stomachs are mostly adapted to eating fibrous foods with very low digestibility," she said. Advertisement Plowman said the monkeys are adjusting well to the vegetable diet. "We reduced the amounts slowly so they had a long period to get accustomed to their new diet. They didn't get a choice but -- unlike children -- they couldn't complain!" she said. Matthew Webb, head keeper of mammals at Paignton, said the new diet has improved the condition of monkeys' coats and the reduced amount of sugar in the food has helped decrease aggressive behavior.