Children as young as eight are dissatisfied with their body size and most 10-year-olds are trying to control their weight, a nationwide study of primary school children has found.
The Australian Institute of Family Studies looked at more than 4000 children aged eight or nine and examined them again at age 10 or 11 to find out how they perceived their body image.
Ben Edwards, the executive manager of the institute's longitudinal study for Australian children, said the report - to be released today - showed that children who were unhappy with their bodies were more likely to have poorer social, emotional and physical health.
Boys and girls - including about 500 from WA - were shown seven drawings of children ranging in size from very thin to obese and asked to choose the pictures that matched their perceived and desired body sizes.
The research found more than half of children between eight and 11 desired a body size slightly thinner than the average, with dissatisfaction levels higher among younger children.
The research also revealed that the majority of the older children had tried to lose or gain weight in the previous year, with 61 per cent of boys and 56 per cent of girls admitting they had tried to manage their weight.
Dr Edwards said the study showed a need for programs aimed at body image and self-esteem to start in the later years of primary school. "We have a lot of prevention programs aimed at teenagers, but less so for that younger age group," he said.
University of WA School of Psychology associate professor Sue Byrne said the results were not surprising and echoed earlier research that found a significant proportion of young girls wanted to be thinner and young boys wanted to be more muscular.
She said it was difficult to manage the problem in young children because there was a risk that prevention programs could do more harm than good by raising concerns about body weight and shape.
"Certainly schools could promote a positive environment in their schools which fosters positive body image," Associate Professor Byrne said.
WA Primary Principals Association president Stephen Breen said most schools would discuss body image in Years 6 and 7.