Scott Martin's poor diet damaged his liver so badly he ended up with severe liver disease.
The 20-year-old, from Farrow Drive, Whitburn, bled to death on Christmas Eve after suffering medical complications after an operation to remove three infected teeth.
Doctors said a liver transplant might save his life but he was scared to have one.
Scott would eat only white sliced bread, fast food french fries, and the occasional plate of baked beans.
He hated foreign food, and refused to eat fresh fruit or vegetables.
His dreadful diet damaged him so badly he developed cirrhosis – a condition more commonly seen in hardened drinkers.
The disease meant he developed a secondary condition, auto-immune hepatitis, which thinned his blood and prevented his body from healing properly.
After Scott, who lived with mum Margaret, 48, and his two sisters, refused to put his name down for a transplant, doctors prescribed medication to control his condition.
He deteriorated so rapidly that by November, when he needed to have the teeth removed, doctors said there was a chance he could bleed to death – but if they did not operate, he could die from the infection.
Scott's teeth were removed but he never recovered and his family watched as he bled to death on Christmas Eve.
His sister Gail Fairweather, a childminder and married mum-of-six, helped care for Scott in his final months.
She said: "In May, he was seen by doctors at South Tyneside District Hospital.
"The doctors sent him to see a specialist at the Freeman Hospital in Newcastle. The specialist found out he had cirrhosis of the liver. We were baffled because Scott was not a drinker.
"But we found out cirrhosis could be caused by bad diet and malnutrition.
"Scott would never eat fruit or vegetables. There was only a few things he would eat – McDonalds' chips were his favourite.
"He would eat toast – but only toast made from sliced white Danish, with a thin spreading of Lurpak butter.
"He would eat baked beans, but only Morrisons' and only now and then.
"Scott did not seem to take his condition seriously, he was laid back about it. But when the doctors said they wanted him to have a liver transplant, he was terrified.
"He had to see a dietician and she gave him loads of special nutritional supplement drinks, but he did not like them. He tried them but did not like the taste and the more ill he got, the less willing he was to try to get them down.
"He began to get weak. For the last six months of his life he was in a wheelchair."
"When they took out his teeth, he bled for four and a half hours before it stopped. He was in the Freeman for three days then came home and began to feel better.
"He agreed to consent to the liver transplant and he was a priority case.
"On the Tuesday before Christmas – December 20– his teeth started to bleed at 10am. It did not stop until 8.50pm.
"On the Friday, his heartbeat stopped twice and doctors had to bring him back.
"I watched the heart monitor get slower, and slower, and slower, then stop. It was 5.45 on Christmas Eve morning."
Scores of friends and well-wishers said their goodbyes to the former Whitburn School pupil at his funeral last week.