It is a worrying trend according to scientists at the Peninsula Medical School in Plymouth, England because being overweight and obese increases the risk of suffering from a variety of illnesses later in life.

Obese children are also more likely to develop Type 2 diabetes, a disease previously seen only in adults.

"A third of the mothers and 57 percent of dads actually saw their obese child as normal," said Alison Jeffery, a member of the research team at the medical school.

"Quite a few parents are not recognizing it as a problem. They are not recognizing the health risks either," she added in an interview.

But Jeffery said it isn't a case of denial.

"We are all used to seeing people who are bigger than they used to be 20 years ago and we just see people who are overweight as normal."

Jeffery, who presented her findings to the Diabetes UK medical conference in Birmingham, England, questioned 300 seven-year old children and their parents about their perceptions of body size.

One third of mothers and half of fathers who were either overweight or obese rated themselves as "about right."

When the child was a normal weight, according to an internationally recognized measurement of obesity in children, most of their parents, regardless of their own size, knew there was no problem.

When the child was overweight but not obese, only a quarter of the parents knew it. But when the youngsters were obese, 40 percent of parents were not concerned about their child's weight.

Health experts have described the increased rates of obesity in children as a serious public health problem because of its link with diabetes as well as an increased risk of heart disease, stroke and other illnesses later in life.

The prevalence of type 2 diabetes in obese children in Poland is nearly four percent. In Hungary it is two percent and 1.6 percent in Germany, according to recent research.

"Diabetes is hugely on the increase and we know that children from as young as the age of seven have metabolic changes that are precursors to diabetes if they are very overweight," said Jeffery.

"They may not be diabetic until they are older but you can see it beginning."