Health
Obesity is caused by two simple factors - an unhealthy diet (typically too rich in sugar and fats) and not doing enough exercise to burn off the calories consumed. Occasionally, there are other factors, for example in a rare genetic condition called Prader-Willi syndrome there may be problems with controlling hunger. Hypothyroidism and Cushing's syndrome can also cause obesity.
These include problems with the joints and bones (such as slipped femoral epiphysis and bow legs), a condition called benign intracranial hypertension that produces headaches and affects vision, hypoventilation (leading to drowsiness during the day, snoring and even heart failure), gall bladder disease, polycystic ovary syndrome, high blood pressure, high levels of blood fats and diabetes.
There are also marked psychological effects leading to low self-esteem.
More and more children in the UK are becoming obese - it's been described as a modern epidemic. Around 27 per cent of children are now overweight and research suggests the main problem is a continual reduction in the amount of exercise children take. Many overweight children have overweight parents - it's often a matter of family lifestyles.
A child's body mass index (BMI) is calculated using the same method as for adults - weight in kilograms divided by height in metres squared - but adult BMI figures must not be used to determine whether a child is overweight or obese. Specific age-adjusted charts are needed.
If you're worried your child is overweight, talk to your doctor and ask for help from a dietician. Avoid starting your child on an aggressive diet. Instead, make long-term changes to healthy eating for all the family, and get your child involved in sport or exercise.
Aim to increase your child's intake of fresh fruit and vegetables (they should be having five portions a day) and reduce fat intake. Try to find healthy snacks they like, and sit down together at least once a day for a balanced meal.
Talk to teachers at their school about what can be done there.
And, because being overweight is often a family problem, measure the BMI of everyone in the family, and start making changes together for a healthy family lifestyle.