Many parents have no idea that their child could be overweight, according to a study which found that offspring who are chronically fat are typically viewed by their mother and father as being of normal weight.

In a survey that involved 277 British children, researchers found that only a quarter of parents recognised when their child was overweight.

Where children were obese, a third of mothers and 57 percent of fathers thought their offspring was “about right,” according to the study, published online Friday by the British Medical Journal (BMJ).

The skewed outlook also applied to the parents’ view of themselves.

Among parents who were overweight or obese themselves, 40 percent of mothers and 45 percent of fathers considered their own weight to be “about right.”

These perceptions are major hurdles to fighting child obesity, because parents who do not recognise the condition will not do anything about it, the authors say.

Child obesity has already reached epidemic proportions in the United States and is spreading rapidly in Britain and elsewhere.