PHUKET - In a sweltering training camp in Phuket, tourists wearing oversized gloves and baggy shorts slam their fists, knees, elbows and feet into heavy bags.
Welcome to the latest craze in extreme fitness - Muay Thai boxing.
With worries growing about the world's bulging waistlines, many foreigners are flocking to Thailand to spend their holidays not on the beach, but to follow a punishing regime of training in Muay Thai and other martial arts.
Some are going to more extreme lengths, quitting their jobs to spend weeks or months training to win their battles with obesity, or to hone their skills in the hope of becoming professional fighters.
Mr Jordan Henderson, 26, left behind his London lifestyle of long work days, parties and overeating after the doctors warned him that he faced looming heart problems due to his weight of nearly 184kg. After one month at the training camp, he shed about 20kg.
"You're in an environment where it's hot all the time, surrounded by people doing fitness," he told AFP after an early morning workout.
"It's about taking yourself out of the box that you live in and just focusing on one thing, and that's to train and lose weight."
Muay Thai, considered Thailand's national sport, is known as the "Art of Eight Limbs" as it combines punches, kicks, elbows and knee strikes.
"It was horrible - the heat and the training, the aches you get and the dramatic diet change," Henderson said.
"I've gone from eating whatever I liked to grilled chicken, steamed vegetables and brown rice - hungry for weeks," Henderson added.
But despite the gruelling regime, he never considered packing his bags and leaving early.
Thailand is home to a flourishing Muay Thai training industry welcoming thousands of guests every year, thanks in part to the popularity of mixed martial arts (MMA) which combines striking and grappling techniques.
"Mixed martial arts is the fastest growing sport in the world and Muay Thai is an integral part of that," said Mr Will Elliot, director of Tiger Muay Thai, one of more than a dozen such training camps in Phuket.
"It's definitely extreme to travel halfway across the world," said Mr Elliot. "But we're in the tropics. It's hot. We're in Thailand, the birthplace of Muay Thai, so it's about immersion."
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