The world's fattest man is nearly 15 stone heavier than first thought, it has emerged.

Doctors believed Mexican Juan Pedro Franco weighed nearly 79 stone when he was taken to hospital earlier this month for surgery to help him walk again for the first time in six years.

But tests have shown his true weight to be 92 stone 9lbs, just over a stone short of record-breaking compatriot Manuel Uribe who reached a peak weight of 94 stone before dying in May 2014.

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Juan Pedro Franco, of Aguascalientes, Mexico, was removed from his home for the first time in six years earlier this year

Doctor Jose Antonio Castaneda, the specialist who is now assisting Juan Pedro, described the find as 'alarming' but said he was still planning to put his patient on a three-month diet before surgery.

'Everything we're doing has been mapped out and if everything goes to plan in a year and a half we'll have him down to between 12 and 14 stone.

'Initially we didn't think he was going to be apt for this treatment because of his level of obesity and a lung problem he suffers, but now we're seeing a more promising horizon.'

He was thought to weigh 79 stone earlier this month, but doctors have now discovered he weighs 92 stone 9lbs

The 32-year-old's plight became world news earlier this month when pictures emerged of him being transported from his home in the central Mexican city of Aguascalientes to a clinic 100 miles away in Guadalajara where he is now being treated.

The suffering Mexican, an accomplished guitar player, had appealed for help in July when he announced he weighed just over 60 stone, revealing he hadn't left his box room for six years and feared he would die after having to quit a special diet which his OAP parents couldn't afford.

He was chubby at school but his weight ballooned after a crippling traffic accident he suffered as a teenager which left him bed-ridden for more than a year, followed by a bout of pneumonia.

He was also featured on 'The World's Heaviest Man', a 2007 television documentary about his bedridden life and attempts to overcome his obesity

Admitting in a recent TV interview he had been ribbed over his size at school, he said: 'When I was six years old I already weighed nearly 10 stone and it's gone up and up since.

'At 17 I weighed just over 36 stone. That was when I had an accident and broke half my body and spent a year and a half in bed.

'I'm looking forward to going out again, driving again, singing. That's what I like doing. God willing, I'll be able to do all those things in the future.'

Local press have described Juan Pedro as the most obese man currently alive in the world, something which is now in no doubt given the news about his true weight

He said today: 'I've been trying to make sure I stay calm and don't get too stressed out.

'I've been doing the lung exercises my doctor has ordered and taking the medicine they've given me, and spend some time every day playing the guitar and a piano.'

Local press have described Juan Pedro as the most obese man currently alive in the world, something which is now in no doubt given the news about his true weight.

Compatriot Manuel Uribe lost half his body weight with the help of doctors and nutritionists after reaching his peak weight - but died in his native city of Monterrey in northern Mexico on May 26 2014.

He was 62 stone at the time.

He drew worldwide attention in January 2006 when he made an emotional plea on a Mexican TV network that prompted both private and public help.

He was also featured on 'The World's Heaviest Man', a 2007 television documentary about his bedridden life and attempts to overcome his obesity.

Nearly 75 per cent of adults in Mexico are considered overweight or obese and the prevalence of diabetes ranks among the highest in the world.