Summary

Overweight and obesity in children and adolescents is a major public health issue in Australia—it is associated with poorer health and wellbeing, worse performance at school, increased health-care costs, and an increased risk of overweight and obesity in adulthood. Reducing and preventing overweight and obesity in children and adolescents are important priorities for Australian policymakers to improve the health of the population.

This report builds on previous AIHW reporting on overweight and obesity by focusing on children and adolescents. It brings together the latest national data to provide insights into patterns of overweight and obesity across population groups and over time. It discusses factors that contribute to overweight and obesity in children and adolescents, summarises the short- and long-term effects of overweight and obesity, and outlines actions that individuals, communities and governments can take to reduce overweight and obesity in this group.

The rate of overweight and obesity has stabilised but is still high

In 2017–18, 1 in 4 (25%) Australian children and adolescents aged 2–17 were overweight or obese, and 1 in 12 (8.2%) were obese.

While the prevalence of overweight and obesity increased for 5–17 year olds between 1995 (20%) and 2007–08 (25%), it has been relatively stable since.

Children, adolescents and young people aged 5–14 and 15–24 in 2017–18 were more likely to be overweight or obese than people of the same age in 1995. The oldest age group (15–24) was also more likely to be overweight or obese in 2017–18 than in 2007–08. The prevalence of overweight and obesity in those aged 5–14 was not significantly higher in 2017–18 than in 2007–08—further evidence that the rate of overweight and obesity in children and adolescents has stabilised in recent years.

Some children and adolescents are more likely to be overweight or obese than others

Aboriginal and Torres Strait Islander children and adolescents, those who have a disability, those who live in Inner regional areas, and those who live in the lowest socioeconomic areas, are more likely to be overweight or obese than other children and adolescents. For example, in 2017–18, 2–17 year olds living in the lowest socioeconomic areas were more than twice as likely to be obese as those living in the highest socioeconomic areas (11% compared with 4.4%).

Although overweight and obesity rates for all Australian children and adolescents have plateaued since 2007–08, rates for Indigenous children and adolescents increased from 31% in 2012–13 to 38% in 2018–19. The biggest increase was for children aged 5–9 (from 27% to 36%).

Overweight and obesity generally increases with age and children regularly move between weight categories

According to results from the Longitudinal Study of Australian Children, the prevalence of overweight and obesity generally increases with age (up to 31% of adolescents at age 16–17). Obesity rates also increase with age over time (up to 11% at age 16–17).

Children involved in the study have their weight measured every 2 years, and for the transition analysis in this report, were classified as either ‘normal or underweight’, or ‘overweight or obese’. While a small proportion of children were overweight or obese every time they were measured, more than 4 in 10 were overweight or obese in at least one of their measurements. Up to 1 in 5 (19%) children and adolescents changed from overweight or obese to normal or underweight (or vice versa) between consecutive measurements. When changing age from 6–7 to 8–9 onwards, generally a higher proportion of children and adolescents moved from normal or underweight to overweight or obese between consecutive measurements than moved in the opposite direction.

Many factors contribute to overweight and obesity

Although overweight and obesity is mainly caused by an energy imbalance (where too much energy is taken in through food and drink, and not enough energy is expended through physical activity), many other factors contribute to the development of excess weight in children and adolescents. These include rapid weight gain during infancy, poor sleep, having parents who are overweight or obese, and exposure to marketing of unhealthy food that is targeted at children and adolescents.

Overweight and obesity has substantial health, wellbeing and financial costs

Children and adolescents who are overweight or obese are more likely to have poorer physical health than children and adolescents who are of normal weight. They may also be subjected to bullying and teasing, which can lead to poorer mental health and quality of life. These negative outcomes worsen as the severity of obesity increases. Obesity is also associated with poorer academic performance, and higher health-care costs. 

Wide-ranging actions can help prevent overweight and obesity

Health professionals can support children, adolescents and their families to prevent the development of overweight and obesity by encouraging healthy diets, physical activity and limited sedentary time. These actions are most effective when accompanied by policies to change environments that are conducive to the development of overweight and obesity in the population. Obesity prevention policies in Australia and worldwide include specific strategies for targeting overweight and obesity in children and adolescents, such as limiting the marketing and availability of unhealthy food and drinks.