Researchers surveyed the parents of 277 children and found that only a quarter recognised when their offspring were overweight. Where children were obese, a third of mothers and 57% of fathers thought their sons and daughters were "about right".
Parents were less likely to recognise overweight boys than girls in the study - more than a quarter (27%) of boys who were overweight and obese were identified as such. This compares with more than half (54%) of parents recognising overweight and obese girls.
The study also revealed that some parents showed a lack of concern towards their children's weight problems. Although more than half of obese children's parents expressed some concern over their child's condition, only a quarter of parents of overweight children described themselves as even "a little worried" about it.
Misjudging weight problems was not confined to their children however. The researchers also found that of those parents who were overweight themselves, 40% of mothers and 45% of fathers judged their own weight to be "about right".
Contrary to previous findings, the study showed there were no differences between the highest and lowest socio-economic groups for the proportion of overweight parents, or for parents misjudging their children's weight. "The longstanding inverse relationship between social class and obesity has been lost in the UK", say the authors.
With more than half of British adults overweight, and obesity among preschool children up by 70% in a generation, these findings are alarming say the researchers. The apparent lack of parental concern about their overweight children is probably due to a lack of awareness, they conclude, but must be addressed if we are to halt an "impending health crisis".