Housebound, barely able to walk and tipping the scales at an astonishing 777lb (55st), Joe Wexler, 31, from Johnson City in Tennessee was, in his words, 'living the nightmare'.

But incredibly, he was for years unable to work out what he was doing wrong and how he had got so large - and even claimed to be eating healthily.

However, when Mr Wexler consulted a bariatric surgeon in a desperate bid to lose weight, he discovered that his 'healthy diet' actually amounted to 10,000 calories a day.

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Healthy diet: Joe Wexler, 31, from Tennessee, thought he was eating a good diet of just two full meals a day

As a result, the 31-year-old, who said his daily intake consisted of 'two full meals plus snacks', was left dangerously overweight - so much so, doctors warned he could die at any moment.

He was also in near constant pain because of the immense strain his vast bulk put on his joints, which he describes as being 'shot'.

'I've been in and out of hospital 10 times in the last nine months,' he revealed while preparing to travel to Houston in Texas to get specialist help.

'I can't go up and down the stairs. I can't even get behind the steering wheel of a car anymore. I've been homebound and it's very lonely.

'I feel like a prisoner inside this body. I wouldn't wish this on my worst enemy. I am living the nightmare. One that I wish very much I could wake up from.'

Unhappy: He couldn't work out why he had gained so much weight and was left deeply unhappy as a result

Pain: Mr Wexler, who at his heaviest weighed 55st, says his joints are 'shot' - making it hard to get around

The product of divorced parents, Mr Wexler says his problems, in particular his emotional eating, stem from the day his mother and father split up.

'Growing up, I could never have imagined that I'd end up like this,' he explains. 'I've always had problems with my weight ever since I was little.

'Bad habits got picked up early. I was allowed to do whatever I wanted, including choosing what to eat.'

Most traumatic of all though was the 'strained' relationship that existed between Mr Wexler and his father.

'The relationship between me and my dad was strained,' he says. 'I think buying those things [treats] was his way of dealing with me.

'I think I would have given up anything I had if he had paid me some attention and I felt like life was punishing me for some sin I didn't commit.

'I ate to deal with my feelings and I never stopped.'

Making the change: Desperate to lose weight, he travelled to Houston to consult a bariatric surgeon

Help required: He was devastated to discover that his healthy diet actually amounted to 10,000 calories

But Mr Wexler, who says he racked his brains in an attempt to find an explanation for his vast size, was also in denial about the amount he ate.

When, desperate to regain some sort of life, he consulted bariatric surgeon Dr Younan Nowzaradan, Mr Wexler was shocked to discover that he was consuming far more than he thought.

'Joe does not understand how much he eats a day,' explained Dr Nowzaradan, one of the U.S' top weight loss specialists.

'He eats at least 10,000 calories a day in order to maintain his weight. Joe has a lot of work to do before he's ready for surgery. He cannot afford to fail at this.'

Nutritionist: He was told to swap his favourite ice cream for frozen Greek yoghurt and to cut down on junk

Getting help: Mr Wexler has now had his surgery and has lost 200lbs (14st) so far

Mr Wexler was given a consultation with a nutritionist but was shocked to discover the amount of fat his favourite Ranch dressing contained.

'Just about everything I eat is bad for me,' said Mr Wexler, who was also told to swap his favourite icecream for frozen Greek yoghurt. 'I had no idea.'

Today, Mr Wexler weighs 600lbs (42st) and has finally had his gastric surgery - but still has some way to go before he can get the job and family of his dreams.

Nevertheless, he says he is now more hopeful of a good future than ever before. 'Words just can't describe how I feel. For the first time in a long time, I feel like I have hope.'