Childhood obesity factsheet


Childhood obesity is when a child has a higher level of body fat than is considered healthy for their age range. A healthy body fat range for your child is measured using their weight and height. 

Being above a healthy weight range can mean that your child is at risk of health problems as they grow, and they are more likely to be above a healthy weight range as adults.

In Australia, 1 in every 4 children and teenagers are above a healthy weight range for their age.

Childhood obesity can be complex and caused by many different factors that overlap. 

Common factors include:

  • eating or drinking more energy and nutrients than the body needs to work well
  • family health history
  • family lifestyle
  • genetic conditions like Prader-Willi syndrome
  • conditions that affect how hormones work, like hyperthyroidism
  • medications to treat illness, like steroids for cancer treatment
  • not being able to access nutritious food or regular movement
  • trauma.

Energy is taken into the body by eating and drinking and is burned off by physical activity and growth. Most children above a healthy weight for their age will be taking in more energy than their body needs or can burn off. The amount of energy needed to grow well is different for every person.

Parents and carers can work closely with a doctor and other health professionals to make sure their child is growing well, in a healthy weight range for their age, and there are no other health conditions. Research shows that getting the whole family involved in healthy eating and movement has the most positive effect on a child's health.

 Signs and symptoms

A child being above a healthy weight for their age is something that you will be able to see. Your child might:

  • have excess body fat in certain areas
  • be growing out of their clothing size faster than normal
  • look bigger than other children of the same age and height.

Other signs and symptoms can include:

  • shortness of breath when doing normal movement, like walking short distances or putting on shoes
  • being very tired
  • sleep apnoea and snoring, when the airways become blocked during sleep
  • pain in the knee or hip joints
  • constipation, or hard, difficult poos
  • more fat tissue than usual in the breast area in boys
  • reflux or vomiting
  • eating past the point of feeling full.

Some older children and teenagers can also have social and emotional problems that are related to their experience of being above a healthy weight, including:

  • low self-esteem
  • bullying
  • eating disorders
  • anxiety
  • depression.  


If your child is above a healthy weight, they will be in the highest weight range outside of what is average for their age group.

The average weight range is calculated using the body mass index, or BMI. The BMI is a general tool that uses your child's height and weight to see where they are compared to the rest of the community. The BMI is a helpful tool for understanding a person's current weight range before investigating further.

Because it is a general tool, it does not consider things like:

  • physical disability, including limb differences
  • physical differences across cultural and ethnic groups
  • muscle.

BMI is a starting point, and is used with other tests, checks and measurements from your child's doctor to diagnose childhood obesity.

Your child's doctor will record height and weight measurements at each appointment to track their general growth and any issues that might come up as they get older.

If you are concerned about your child's weight and growth, speak to your local doctor.


Parent and carer support is the most important part of helping your child keep a healthy weight range for their age. You can do this by making positive changes to eating and movement in day-to-day life and encouraging friends and family to do the same.

You can support your child by:

  • learning about nutrition, food and healthy choices
  • providing nutritious foods and drinks in the home
  • avoiding using food and drink as a reward
  • modelling positive eating behaviours, like eating at the table away from the TV
  • modelling positive movement, like going for regular walks outside or playing sports.

Children who are above a healthy weight range or obese due to medical conditions or medication will need support at home from parents and carers, along with further treatment with their doctor to manage their health.

Supporting your child to keep a healthy weight range for their age can lower the risk of severe health issues like:

  • stress on bones and joints, including the hips, legs and ankles
  • sleep problems, like sleep apnoea
  • hypertension, or high blood pressure
  • high cholesterol
  • type 2 diabetes.


Making positive changes to eating and movement and keeping a healthy weight range can seem like a big task, but it isn't as complicated when you have good support from your family, friends and health professionals.

Positive changes can be small and realistic, building up to bigger positive changes. Involving the whole family will give your child the best support for being healthy and growing well.

Last updated Tuesday 28th November 2023


This factsheet is provided for general information only. It does not constitute health advice and should not be used to diagnose or treat any health condition.

Please consult with your doctor or other health professional to make sure this information is right for you and/or your child.

The Sydney Children’s Hospitals Network does not accept responsibility for inaccuracies or omissions, the interpretation of the information, or for success or appropriateness of any treatment described in the factsheet.

© Sydney Children’s Hospitals Network 2024

This factsheet was produced with support from John Hunter Children's Hospital.