A third of parents underestimate their child's weight

Many parents are afflicted by 'weight-blindness', unable to recognise their child is overweight unless they are extremely obese, new research has found.  

The research discovered that just under a third (31 per cent) of the parents underestimated where their child's body mass index (BMI) was on obesity scale.

The scale classifies children as very overweight (or obese), overweight, a healthy weight, or underweight.

Just four parents described their child as being very overweight despite 369 children being officially identified as such (1 per cent) and fewer than 1 per cent overestimated their child's weight status.

According to official guidelines, children are classified as overweight at the 85th centile and very overweight (or obese) at the 95th centile.

The team estimated that for a child with a BMI at the 98th centile there was an 80 per cent chance that the parent would classify their child as a healthy weight.

However, they recognised that parents became more likely to classify their child as overweight when the child had a BMI above the 99.7th centile.

The study found that parents were more likely to underestimate their child's weight if they were black or south Asian, from more deprived backgrounds, or if the child was male. 

Researchers suggested that if parents cannot identify when their child is overweight, this throws into question the effectiveness of public health campaigns aiming to address obesity in the home.

Recent research found that a third of children in England are now classed as overweight or obese. 

Parents might underestimate their children's weight due to be fear of being judged, unwillingness to label a child as overweight, and shifting perceptions of normal weight because of increases in body weight in general.

They said evidence suggests that parents who recognise their child's weight on the BMI chart are more likely to perceive potential health risks.

The study was led by the London School of Hygiene & Tropical Medicine and UCL Institute of Child Health.

It involved questioning the parents of 2,976 children in five primary care trusts: Redbridge, Islington, West Essex, Bath and North East Somerset, and Sandwell.

The team said the research could help evaluate how effective public health interventions for obesity in children are likely to be in different groups of the population.

Senior author Dr Sanjay Kinra, of the London School of Hygiene & Tropical Medicine, said: 'If parents are unable to accurately classify their own child's weight, they may not be willing or motivated to enact the changes to the child's environment that promote healthy weight maintenance.'

Co-author Professor Russell Viner, of the UCL institute of Child Health, said: 'Measures that decrease the gap between parental perceptions of child weight status and obesity scales used by medical professionals may now be needed in order to help parents better understand the health risks associated with overweight and increase uptake of healthier lifestyles.'

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