Back to Impacts

Impacts: Health impacts

Impact of obesity on children

Last updated 14-05-2021

Obesity is a direct cause of physical and psychological ill health during childhood and adolescence, as well as being a strong predictor of obesity and its associated health consequences during adulthood.

Key Evidence


Sleep problems linked to obesity can contribute to poor concentration at school


Obese children are two to three times more likely to spend time in hospital


Children with a high Body Mass Index (BMI) who avoid obesity in adulthood can substantially reduce cardiovascular risks

The first 1000 days of life (from conception to 2 years) is a critical period in determining the risk of future obesity.1 Pregnancy risk factors include high maternal body mass index (BMI), smoking during pregnancy, gestational diabetes, excessive gestational weight gain and low or high birth weight.2 In early life, risk factors include the early introduction of solids before four months and formula feeding practices (breastfeeding is protective).2 For the majority of these pregnancy and early life risk factors, children from low socioeconomic backgrounds are more likely to be affected.3

In addition to developmental risk factors, the environment surrounding young children also influences their risk of obesity. Children inherit family eating and physical activity behaviours, ensuring that behavioural influences continue through generations.4 Broader cultural norms play an important role, including promotion of unhealthy foods and a decline in physical activity for transport or play.4

Obesity is a direct cause of physical and psychological health consequences during childhood and adolescence, as well as being a strong predictor of adult obesity and its associated health consequences.4

A summary of obesity-related health problems in children and adolescents is below.

System Complication Comment
Psychosocial Decreased self-esteem, social isolation and discrimination, bullying, body image disorders, bulimia, learning difficulties, altered mood, longer term issues with poorer social and economic standing (especially females) Highly prevalent and increased with age; girls particularly at risk; associate with reduced quality of life
Endocrine and reproductive system Insulin resistance, glucose intolerance, increased risk and development of type 2 diabetes mellitus (in adolescence and adulthood), menstrual irregularities, polycystic ovary syndrome, delayed or accelerated puberty Prevalence of type 2 diabetes mellitus increased with rising obesity rates: disease progression in type 2 diabetes is accelerated compared with adults and children with type 1 diabetes
Respiratory Obstructive sleep apnoea, asthma, reduced exercise tolerance Sleep-disordered breathing highly correlate with obesity; may contribute to poor concentration and school performance
Gastrointestinal Non-alcoholic fatty liver disease (NAFLD), gastro-esophageal reflux, gallstones Prevalence of NAFLD high; may progress to cirrhosis and liver failure
Orthopaedic Lower limb joint pain, increased risk of falls, sprains and fractures, back pain, slipped capital femoral epiphysis (around puberty), Blount disease (tibia vara), flat feet Affects mobility and physical activity capacity
Cardiovascular Hypertension, dyslipidaemia (raised triglycerides and LDL cholesterol, low HDL cholesterol), raised inflammatory markers, left ventricular hypertrophy, increased risk of coronary artery disease in adulthood Development of metabolic syndrome a predictor of adult cardiovascular disease
Skin Acanthosis nigricans, striae, acne, intertrigo, hirsutism, chafing, excess sweating May contribute to poor self-image and low self-esteem
Neurological Benign intracranial hypertension
Dental Increased risk of dental caries
Vitamin and mineral deficiencies Iron deficiency anaemia, vitamin D deficiency, vitamin B12 deficiency From poor dietary intake and obesity-associated inflammatory pathophysiology
General Exacerbation of pre-existing medical issues e.g. constipation, enuresis, gastro-esophageal reflux

Source: Reproduced from Children's Hospital at Westmead Sydney, Submission 44, Inquiry into the Obesity Epidemic in Australia.

A study of pre-school aged children aged 2 to 5 years in Sydney found obese children were two to three times more likely to spend time in hospital compared to children within a healthy weight range.5 The authors’ analysis of the reasons for hospitalisation was consistent with the known increased prevalence of various disorders in young children with obesity, including obstructive sleep apnoea, asthma, airway obstruction, fractures, sprains and musculoskeletal pain. They found that the additional healthcare cost for a child with obesity was $825 for general patients and $1332 for concession card holders, when compared to a child of a healthy weight over the three-year follow-up period of the study.5

While childhood BMI is a predictor of adult BMI, having a high BMI in childhood but avoiding obesity in adulthood leads to a substantial reduction in cardiovascular risk.6 A large analysis found overweight or obese children who were obese as adults had increased risks of type 2 diabetes, hypertension, dyslipidemia (abnormal levels of lipids in the blood), and carotid-artery atherosclerosis. The risks of these outcomes among overweight or obese children who became non-obese by adulthood, however, were similar to those among adults who were never obese.6


1. Woo Baidal JA, Locks LM, Cheng ER, Blake-Lamb TL, Perkins ME, et al. Risk Factors for Childhood Obesity in the First 1,000 Days: A Systematic Review. American Journal of Preventive Medicine, 2016; 50(6):761-779.
2. Centre of Research Excellence in the Early Prevention of Obesity in Childhood. Submission 10, Inquiry into the Obesity Epidemic in Australia. 2018. Available from:
3. Cameron A, Spence A, Laws R, Hesketh K, Lioret S, et al. A Review of the Relationship Between Socioeconomic Position and the Early-Life Predictors of Obesity. Current Obesity Reports, 2015; 4(3).
4. World Health Organization. Report of the Commission on Ending Childhood Obesity. Geneva, Switzerland 2016. Available from:
5. Hayes A, Chevalier A, D'Souza M, Baur L, Wen LM, et al. Early childhood obesity: Association with healthcare expenditure in Australia. Obesity, 2016; 24(8):1752-1758.
6. Juonala M, Magnussen CG, Berenson GS, Venn A, Burns TL, et al. Childhood Adiposity, Adult Adiposity, and Cardiovascular Risk Factors. New England Journal of Medicine, 2011; 365(20):1876-1885. Available from: