A new study has found that most parents of kids aged 4 or 5 are not aware if their children are overweight or obese.
Researchers from the University Medical Centre Groningen in The Netherlands reached the conclusion after observing 800 parents and 439 children who took part in study.
Among those participating five per cent of the children were overweight, four were obese and the rest were normal weight.
It was found that 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.
Professor Pieter Sauer from the Department of Paediatrics, said: "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.
"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 parents were made to choose their child's body shape from seven different sketches.
It was noted that 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.
Sauer said: "It's estimated that 10 per cent of children in The Netherlands are overweight, compared with 20 per cent in the USA. However, public perception of what is a normal weight has shifted upwards because more people are overweight or obese.
"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."
Sauer concluded: "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."
The study has been published in the February issue of Acta Paediatrica.