A morbidly obese wild monkey who gorged himself on junk food and soft drinks left behind by tourists has been rescued and placed on a strict diet of lean protein, fruits and vegetables.

Wildlife officials caught the chunky monkey - nicknamed "Uncle Fat" by locals at a market in Bangkok - after photos of the animal started circulating on social media last month.

Wild monkeys roam free in many parts of Thailand, attracting tourists who feed and play with the animals. Most of the monkeys are macaques like Uncle Fat, and they typically weigh around 20lb.

Uncle Fat weighs three times that, tipping the scales at around 60lb.

"It was not easy to catch him," said Kacha Phukem, the wildlife official who conducted the capture and rescue on April 27. "He was the leader of his pack, and when I tried to go in, I had to fight off a flock of them with sticks."

The subordinate monkeys fed into Uncle Fat's bad habits.

"He had minions and other monkeys bringing food for him but he would also redistribute it to younger monkeys," said Supakarn Kaewchot, a vet in charge of the monkey's diet. "He is now in a critical condition where there is a high-risk of heart disease and diabetes."

Uncle Fat is believed to be aged between 10 and 15. To help him lose weight, his new diet is limited to 14oz of lean protein, fruits and vegetables twice a day. Ms Supakarn said she hopes that within a few months they can consider releasing him into the wild.

She said Uncle Fat is an example of why people should not feed wild monkeys unhealthy food.

"I understand that people feel sorry for the monkeys and want to feed them when they see them. But please don't feed them food that people like to eat like snacks and soda. It is very bad for their health and the problem is entirely man-made."