Researchers from the Institute of Child Health and Great Ormond Street Hospital have dubbed the disease Food Avoidance Emotional Disorder (FAED).

Children with the illness want to get better and gain weight, but are afraid to eat - unlike those with anorexia nervosa who are scared of putting on weight.

The researchers said FAED children tended to be younger than those with anorexia nervosa and were more likely to be boys and of non-British origin.

Anorexia nervosa mainly affects young girls with a poor self image. Most are aged around 13-and-a-half.

Stunted growth

The average age of children with FAED is just under 12 years old.

The researchers found that the young age of onset of the illness could lead to "significant stunting". But they said that this could be reversed if children received proper treatment.

Dr Dasha Nicholls of the Institute of Child Health said she saw around 60 children a year with eating disorders.

Half had anorexia nervosa, but as many as a quarter were simply afraid to eat.

Twice as many girls had the disorder as boys, but nine times as many girls had anorexia nervosa as boys.

A large proportion of the children from ethnic minorities with the fear were Asian.

Dr Nicholls said this could be to do with the way Asian families interpret eating disorders.

They might, for example, be less likely to put an eating disorder down to fear of putting on weight.

Fear of choking

She said there were many reasons a child might become afraid to eat.

Anorexia nervosa tends to affect girls, but boys are more likely to have FAED

The children she saw were aged between seven and 15.

Most had grown normally until suddenly something went wrong and they began to avoid food.

Some were worried they would choke or be sick if they ate. Some complained of stomach pains.

Dr Nicholls said one reason for the disease could be an earlier illness which caused a child to have a bad experience with food.

"They may have felt anxious and their throat tightened and they were unable to swallow and they linked this feeling to food," she said.

The research team also found that children with the disorder tended to go to doctors because of physical rather than psychological problems associated with the illness.

"Losing weight is always abnormal for children as they are growing," said Dr Nicholls.

She added that doctors often felt the reason for food avoidance was solely physical and began lots of investigations.

She said they should consider that the problem may also be psychological.

She added that children with FAED might also have a physical problem which caused their fear.

Extremely thin

Some of the children she has seen are thinner than children with anorexia because doctors have spent so much time investigating the cause rather than treating the disease.

At Great Ormond Street Hospital, treatment includes parental counselling.

This is tailored to each individual child and involves looking at what the fear is and how much food the child needs to eat and when.

Some children are afraid to eat because they feel full very quickly and they should eat small meals regularly rather than big meals.