- Of the 34 member countries of the Organisation for Economic Co-operation and Development, obesity prevalence is highest in the United States, with Australia ranking fifth for girls and eighth for boys. Curbing the problem is achievable and can be realised through a combination of smart governance across many sectors, community initiatives, the support of individual efforts, and clinical leadership.
- At 5 years of age, one in five Australian children are already affected by overweight or obesity; obesity prevention strategies must therefore start before this age. There is strong evidence that reducing screen time and promoting breastfeeding in 0–2-year-olds are effective interventions in the early years.
- The main behavioural risk factors for obesity are overconsumption of energy-dense, nutrient-poor foods and a lack of physical activity. Emerging evidence suggests poor sleep quality and duration and high amounts of sedentary time also play a role.
- Systems-based policy actions may change long term obesity prevalence in children by targeting the food environment through nutrition labelling, healthy foods in schools, restricted unhealthy food marketing to children, and fiscal policies to reduce consumption of harmful foods and sugar-sweetened beverages.
- Macro-environmental factors influence obesity risk. Public transport policy and the built environment (proximity to parks, bike paths, green space, schools and shops) influence play time spent outdoors, walking and cycling. Greater access to parks and playgrounds and active commuting are associated with lower body mass index.
- Australian interventions have largely employed individual level approaches. These are important, but of limited effectiveness unless priority is also given to policies that reduce obesity-conducive environments.
- Clinicians can provide anticipatory guidance to support healthy weight and weight-related behaviours, including weight monitoring, early feeding and children’s diets, physical activity opportunities, and limited sedentary and screen time.
- Investigations in children with obesity usually include liver function tests and measuring fasting glucose, lipid and possibly insulin levels. As obesity can be associated with micronutrient deficiencies, it may be prudent to check full blood count and iron, vitamin B12 and vitamin D levels. Endocrinological assessment is usually not needed. Second line investigations may include liver ultrasound, oral glucose tolerance testing and sleep study.
- Traditional treatment of child and adolescent obesity has focused on family-based, multicomponent (diet, physical activity and behaviour change) interventions, although these lead to small and often short term weight reductions (mean, − 1.45 kg; 95% CI, 1.88 to − 1.02). Nevertheless, these principles remain core interventions in children and adolescents with obesity.
- A very low energy diet should be considered in adolescents with severe obesity or obesity-related comorbidities, and for adolescents who have not achieved weight loss following a more conventional dietary approach.
- Pharmacotherapy confers only small reductions in weight; for example, effect size for metformin is − 3.90 kg (95% CI, − 5.86 to − 1.94).
- Bariatric surgery should be considered in adolescents over 15 years of age with severe obesity (body mass index > 40 kg/m2, or > 35 kg/m2 in the presence of severe complications).
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