Seven in every ten obese adults underestimate how much someone weighs, a new study has found.
People of normal weight make this mistake much less often, according to researchers at the Columbia University Medical Center in the US.
Mothers of overweight or obese children also tend to misjudge their children's size, as youngsters misjudge their obese mothers' size, said lead author Tracy Paul, now at Weill-Cornell Medical College.
If abnormal weight among children is not addressed in a timely way, it can set in motion life-long distorted perceptions of what is acceptable and healthy, and contribute to adolescent and adult obesity, researchers said.
However, prevention efforts are often challenging because many parents of obese children do not try to prevent their children from becoming obese.
Paul's team tested the assumption that this happens because parents often do not perceive weight as a problem, or do not see the link between obesity and health problems.
They queried 253 mothers and their children at an outpatient pediatric dental clinic at Columbia University Medical Center about their perceptions of what healthy and ideal body sizes are. Most participants were Hispanic (82.2 per cent).
The researchers found that 71.4 per cent of obese adults and 35.1 per cent of overweight adults underestimated size, compared to 8.6 per cent of people of normal weight.
Among overweight and obese children, 86.3 per cent and 62.3 per cent respectively think they weigh less than they actually do, versus 14.9 per cent of children of normal weight.
Mothers of overweight children had a particularly poor showing. Eighty per cent of them underestimated their child's weight, compared to 7.1 per cent of mothers with normal weight children and 23.1 per cent of mothers with obese offspring.
Children with obese mothers, too, found weight difficult to judge, with the vast majority of them incorrectly classifying an adult's size.
The study appears in the Journal of General Internal Medicine published by Springer.
