Half of the mothers who took part in a study thought that their obese four or five year-old was normal weight, as did 39 per cent of the fathers, according to the February issue of Acta Paediatrica.
When it came to overweight children, 75 per cent of mothers and 77 per cent of fathers thought that their child was normal weight.
More than 800 parents of 439 children took part in the study, carried out by researchers from the University Medical Centre Groningen in The Netherlands. Five per cent of the children were overweight, four were obese and the rest were normal weight.
"As well as asking them to provide information on their child's height and weight, they were also asked to provide information on their own vital statistics" says Professor Pieter Sauer from the Department of Paediatrics.
"We used this to compare the parents' assessment of their children with their own weight to see if there was any correlation. Data on the child and both parents was provided in 397 cases."
The study showed that:
- Mothers and fathers of overweight and obese children were significantly heavier than the parents of normal weight children.
- Parents were more aware of their own weight. 83 per cent of the overweight mothers and 78 per cent fathers realised that they were too heavy, as did 98 per cent of the obese mothers and 96 per cent of the obese fathers.
- When asked to choose their child's body shape from seven different sketches, 97 per cent of parents with normal weight children chose a lighter sketch than the data they provided indicated.
- The same was true of 95 per cent of the parents of overweight children and 62 per cent of the parents of obese children.
- Parents of normal weight children tended to think their child was one sketch slimmer than their Body Mass Index (BMI) indicated and parents of obese children often chose sketches that were three slimmer.
- Most of the parents did not worry about their child's weight, but the mothers of obese children were more likely to be concerned than the mothers of normal weight children (44 per cent versus seven per cent).
- Parents of overweight and obese children did not think their children were less active than others and 94 per cent felt they could influence their child's food choices and eating habits.
- Approximately four out of five parents said they would want to receive information or guidance if their child was overweight, regardless of how they viewed their child's current weight.
"Overweight children are very likely to become overweight teenagers and adults, so intervening when they are aged between three and five could prevent weight problems later in life.
"It is vital that parents are aware of their children's weight if we are to prevent them becoming obese in later life.
"The fact that the parents in our study perceived their children to be lighter than their BMI indicated is cause for concern.
"Our findings point to the need for health education programmes that encourage parents to recognise what is a normal healthy weight for their children and work with health professionals to tackle any weight problems."
Explore further: Parents blind to their children's weight
How do parents of 4 to 5-year-old children perceive the weight of their children? Luttikhuis et al. Acta Paediatrica. 99, pp 263-267. (February 2010). DOI: 10.1111/j.1651-2227.2009.01576.x