Now, the Belfast teenager is making a documentary about his quest to lose weight and conquer the psychological damage caused by a lifetime of bullying. The movie is due to be completed by December next year, and should be screening in a cinema near you.

The teasing and humiliation started when Bloch was five. "I've no idea why the bullies chose me, " he says. "I don't know what made me different, but the chief bully was very angry, and I was the focus of his anger."

By the age of eight, Bloch was using food as a comfort mechanism. When he was 12 years old, and going into his first year in secondary school, he weighed 14 stone. His confidence was shattered, and he had no friends. "I found it almost impossible to trust anyone my own age, " he says.

"I was totally withdrawn into myself."

Unfortunately for Bloch, the group of boys who had bullied him in primary school also progressed to the same secondary school. The bullying continued, all of it psychological . . . until one day in the school corridor. "For no particular reason, one of them managed to flip me off my feet onto the stone floor, " says Bloch. "I really hurt my back. And it was terrible, because I was bigger than the boy who attacked me. I should have been able to stand up for myself. But at that point, I just had no self esteem."

After that incident, Bloch had a breakdown. He changed schools and went to therapy sessions.

Then, last summer, he saw an ad for a US camp that helped people lose weight. "I was almost at 20 stone at that stage, so I called up immediately, " he says. "The camp was a brilliant learning experience. It made me come out of my shell, because I was with 30 other people who had enountered the same difficulties as myself. From a social perspective, it was a revelation."

Over the two-month camp, Bloch lost two-anda-half stone. Then he returned to Belfast, and to school, and returned to depression. "There was nothing wrong at all with the school I was in, " he says. "It's just that I associate the whole routine of school with daily humiliation and misery. So I started eating again, and around three months ago I weighed myself and I was my heaviest ever . . . 300 pounds (21 and a half stone)."

The number on the scales really shocked Bloch, and for the first time in his 16-year-old life, he began to worry about dying young. "I couldn't get the courage to tell my parents what I'd ballooned to. None of my clothes from the States fit me any more, and almost none of the shops in Belfast sold clothes that would fit me. And I just realised that there's so much more I want to do in life. I don't want to die in my 20s."

Originally, Bloch planned to keep a personal diary of his weight-loss journey. "But then I realised I could do so much more, " he says. "I could get the message across that fat people are real people with real problems, and that bullying continues to be socially acceptable . . .

despite the fact that it can scar people for life."

Bloch's parents funded the camera equipment needed to film the documentary. The 16year old has used the internet to learn about filming techniques, and has already been shooting for a couple of months. He has lost one-anda-half stone so far, and his target is to be 13 stone by his 18th birthday on 23 October 2007.

The documentary . . . to be called The Weighting Game . . . will be ready for screening by December 2007.

Bloch will be distributing his film to cinemas in the North, and, he hopes, the Republic and Britain too.

"It has to work now, " he says. "People are going on to the website and taking notice of what I'm doing, so I have to succeed now. My next project will be to set up a support group for male teenagers with weight problems, because they are a totally neglected group. If everything goes to plan, this film will just be the beginning."