Emergency services rushed to the home of Liam Johnston after he suddenly took ill.
But despite their desperate attempts to save his life, Mr Johnston was pronounced dead shortly afterwards.
It is thought that two separate teams of firemen were called in to help medical staff transport the young man's body from his home in Livingston.
Staff at the Edinburgh City Mortuary later carried out a post-mortem examination, where Mr Johnston was reportedly weighed in at 66 stone - one of the heaviest ever recordings made in the UK.
Yesterday, at her home in Livingston, his mother, Mary, 41, who also has a daughter, Allana, 20, was too upset to speak of her son's death.
A Police Scotland spokesman said: "We can confirm that officers were called to assist the Ambulance and Fire Services at an address in Livingston where a 22-year-old man was taken ill on Thursday morning.
"A report surrounding the circumstances of his death - which are not being treated as suspicious - will be sent to the Procurator Fiscal at Livingston. His next of kin has been notified."
According to previous reports, Mr Johnston's claimed his obesity was the result of entrenched mental health issues which persisted for a number of years.
As an 18-year-old, he tipped the scales at 21 stone only to find his weight had almost doubled shortly after his 21st birthday.
Mr Johnston soon became socially-isolated as he struggled to cope with the ridicule his family faced as a result.
Known to be a recluse in his home, he refused to see anyone but close family members.
Around nine months ago, he gave an in-depth interview where he spoke of the emotional and social distress his obesity had caused.
While saying that he had been chubby as a child, Mr Johnston admitted he was ashamed as his weight spiralled out of control.
He said: "I'm trying to get rid of this weight once and for all. I don't want to put my family through the ridicule. I'm doing my best to sort my life out.
"I've hid myself away from the outside world, ashamed at the size I had become.
"You've no idea how difficult it is to go through something like that. To know that no one was there to talk to, for well over a year."
At the time of his death, Mr Johnston was hoping to have a gastric band fitted in a last-ditch effort to arrest his weight gain.
The surgery is regarded as a 'last resort' and is only available on the NHS to treat people with potentially life-threatening obesity. It is only carried out when other treatments, such as lifestyle changes, have failed.
Those who knew Mr Johnston claimed he had suffered from depression and rarely ventured outside. Last summer, he was charged with fraud after allegedly using a stolen credit card to order takeaway pizzas.
However, he was unable to unable to appear before the court with his lawyer claiming he was unable to get out of his single storey terraced house
Mr Johnston said he was 'disgusted' with his actions and that he had shamed himself and his family. The proceedings against him were still outstanding when he died.