Early interventions are effective in helping children to maintain and achieve healthy weight
There is strong evidence for guidance on breastfeeding, introduction to solids, healthy diets for young children, physical activity, limiting screen time and improving sleep
There is also evidence for effective obesity prevention in early care, school and community settings
Systems-based policy actions are needed to change long term obesity prevalence in children
This page has been written by Dr Seema Mihrshahi and Professor Louise Baur with Kate Hagan
Childhood obesity is one of the most important public health challenges in this century and the worldwide prevalence of overweight and obesity is rising rapidly, even among young children.1 In Australia, there are significant disparities in prevalence rates between children and adolescents from low and high socio-economic status (SES). An analysis of overweight and obesity trends in children and adolescents in NSW over 30 years (1985–2015) found the risk of overweight and obesity was significantly higher for low-SES children and adolescents, compared to their high-SES peers.2 (Significant disparities in prevalence rates between children and adolescents from low and high-SES backgrounds began in 1997 for obesity and 2010 for overweight.)
Strong evidence links childhood obesity to a myriad of problems including cardiovascular risk factors, chronic diseases such as asthma, and poor mental health (for more information see The impact on children). Carrying excess weight in childhood predicts the development of obesity, both in later childhood and in adulthood. Reductions in weight can be hard to achieve once established which makes the prevention of obesity in early life critical.
Overall, a Cochrane review found evidence that combined diet and physical activity interventions can reduce the risk of obesity in children aged 0–5 years, 6–12 years and 13–18 years.3 Interventions that only focus on physical activity can reduce the risk of obesity (BMI) in children aged 6 to 12 years and 13 to 18 years but do not appear to be effective in children aged 0–5 years. Interventions that only focus on diet may be beneficial in children aged 0–5 years, but there is no evidence that they are effective in children aged 6–12 years and 13–18 years. The review found that interventions to prevent childhood obesity do not appear to result in adverse effects or health inequalities.
Home-based settings in young children (0–2 years)
One in four Australian children are already affected by overweight or obesity at the time they start school.4 Early life is an opportune time to intervene, particularly because many obesity-related behaviours are established in, and track from, early childhood. These include poor diet quality, decreased physical activity, increased sedentary behaviours and decreased sleep duration. Life-course studies suggest that interventions in early life, when biology is most amenable to change, are more likely to show positive outcomes on weight and weight-related behaviours.
Several obesity prevention interventions have been undertaken in children aged 0–2 years in Australia and New Zealand. One such intervention is Healthy Beginnings, where mothers in a socially disadvantaged region of Sydney were visited at home by nurses beginning in late pregnancy continuing to age 2 years.5 Advice on breastfeeding, introduction to solids and appropriate complementary feeding, healthy diets for young children, physical activity, limiting screen time and methods to improve settling and sleep were given over the two-year period. Healthy Beginnings is now being implemented on a wider scale, through telephone consultations and text messages.6
In Melbourne, the INFANT program, which is based on the Infant Feeding Activity and Nutrition Trial, involves anticipatory guidance and discussion on introduction to solids, tummy time and physical activity through parents groups.7 The program is being offered in Victoria to all local governments and has also been enhanced by use of web-based materials, apps and social media engagement.8
Encouragingly, a pooled analysis of four Australasian early interventions, including data from Healthy Beginnings and INFANT, has shown that, compared with usual care, early interventions do lead to improvements in Body Mass Index (BMI) at ages 18–24 months. In addition, there were improvements in behaviours known to be related to reducing obesity, such as increasing breastfeeding duration and a reduction in TV viewing time.9
Childcare and preschool settings
Early childhood education and care centres are in a unique position to provide a healthy environment for children to eat, play, and grow and can also be central to educating parents about healthy eating and activity habits.
A review of recent early care interventions has shown that higher intensity interventions with high parent engagement and environmental and policy components are more likely to be effective in helping children to maintain or achieve healthy weight.10
Strategies to improve outcomes in early care include changing menus to serve children age-appropriate healthy foods, and limiting unhealthy food, sugary drinks and juice. Programs that provide structured physical activity and opportunities for active play and limiting screen time have been implemented. Nutrition education for educators and parents has also been used.
Munch & Move is an initiative that offers training and resources to educators working in early childhood education and care services in New South Wales. The training is based on increasing six key health promoting messages, encouraging and supporting breastfeeding; choosing water as a drink; choosing healthier snacks; eating more fruit and vegetables; getting active every day; and turning off the television or computer. The program has been implemented state-wide and the evaluation has shown improvements in the delivery of training, practice achievements and program adoption in early childhood education and care centres, especially in disadvantaged and remote communities.11
Schools are an ideal setting for promoting health and most obesity prevention efforts in older children (5–12 years) and adolescents (13–18 years) are centred in schools or in after-school settings. It is important to recognise that, once established, obesity is very difficult to reverse and there has been limited success in school-based interventions for reducing overweight and obesity. The most recent research suggests that school-based interventions with combined diet and physical activity components including a home element may have a beneficial effect on diet and physical activity for children.12
Many interventions have included changes to the school curriculum to integrate games and stories to teach nutrition and increased time for sports and outdoor activities at recess and lunch-time. There is also emerging evidence that healthy school canteens and food provision, interventions that reduce portion size, and healthy food policies may be effective for improving diets. For promoting physical activity, some schools have encouraged active travel and walking or cycling to school.
Novel school obesity prevention programs have recognised that students themselves serve as powerful motivators and role models for others, and have implemented peer education and leadership programs. The Students As LifeStyle Activists (SALSA) program in western Sydney uses a peer educational model, driven by students, to promote physical activity and healthy eating in a supportive high school environment. Under the SALSA program, university students train year 10 students to become effective peer leaders, who in turn educate their younger year 8 peers. Early evaluation of the program shows an increase in fruit and vegetable consumption, reduced consumption of sugar-sweetened beverages and reduced screen time.13
An intervention delivered to adolescents at a school in Texas, US, framed food marketing as manipulative and incompatible with values of social justice and autonomy from adult control.14 It was successful in leading adolescent boys – a hard to reach group – to make healthier food and drink choices at the school canteen and this was sustained at three months. The intervention arm was delivered over two classroom sessions on consecutive days and included an activity in which students were shown images of food ads on tablet computers that allowed them to draw or write over the ads to “make them true” (as shown).
Community-wide approaches show promise as a way of addressing complex local drivers of childhood obesity, through the implementation of multiple strategies across multiple settings.15 Interventions for childhood obesity in a community setting often involve additional settings such as home, school and primary care.16 Trials to date have mostly involved community settings such as gyms, recreation centres or playgrounds, with the addition of family-centred components such as group workshops and home visits.
In Victoria, an innovative systems approach to mobilising community action, the Whole of Systems Trial Of Prevention Strategies for childhood obesity (WHO STOPS) intervention,17 is being implemented in 10 communities in the south-west of the state. The intervention is adaptive and co-created with communities. Community leaders identify areas where actions can be taken to reduce obesity related risk factors. Organisations within their communities (including local government, health services, schools and sporting clubs) plan, support and monitor the community-led actions. The primary outcome is childhood obesity prevalence among grade two, grade four and grade six students, and evaluation of this approach is continuing.17
An earlier trial in the town of Colac, also in Victoria’s south-west, successfully used a multi-setting, multi-strategy approach and community capacity-building principles to prevent obesity in children aged 4 to 12 years. The intervention program, Be Active Eat Well, was designed and implemented by key organisations in Colac including local government, health and community groups between 2003 and 2006.15 It sought to enhance the skills of health professionals and stakeholders, reorient organisational priorities, develop networks and partnerships, build leadership and community ownership and develop sustainable health-promotion strategies.
The program resulted in significant improvements to school environments and policies and some nutrition and physical activity behaviours. Children in Colac had smaller increases in weight and waist circumference compared to a control group over the 3-year intervention period. Importantly, the program had a greater impact in children from more disadvantaged households, there was no evidence of harm, and the programme was cost-effective.18
Focusing on the upstream determinants of obesity
The approaches described above, most of which operate close to the individual child or young person, are important, but of limited effectiveness unless priority is also given to policies that reduce obesity-conducive environments. Central to reducing the prevalence of childhood obesity will be implementing policy actions that target the food environment and have the potential to produce long-term changes in the prevalence of overweight and obesity in children.119 These include effective nutrition labelling, initiatives to make healthy foods available in school, restrictions on unhealthy food marketing to children, fiscal policies to reduce consumption of sugar sweetened beverages as well as macro-environmental factors such as improving public transport and the built environment (proximity to parks, bike paths, green space, schools and shops) which influence play time spent outdoors, walking and cycling.