According to the Westmead Children's Hospital in Sydney, demand for weight management services has increased fivefold in the past three years and has prompted the appointment of a specialist dedicated to dealing with children who are seriously overweight.

The appointment of Dr. Shirley Alexander comes as the number of overweight and obese children surges to more than 1.5 million and health systems are struggling to cope.

Dr. Alexander says the numbers of overweight and obese children and adolescents have tripled in some areas in the past 20 to 30 years and there are not the resources to deal with the growing demand for services.

Westmead hospital alone treated 17 morbidly obese children in 2005 and this year this number is predicted to rise to at least 90.

Dr. Alexander's role will involve educating parents about healthy food and exercise options and treating those whose weight is affecting their health.

Dr. Alexander says overweight teenagers have a higher risk of growing into overweight adults, with an increased chance of developing type 2 diabetes, cardiovascular disease, metabolic syndrome, arthritis, sleep apnoea and non-alcohol fatty liver disease.

Dr. Alexander says preventing obesity is obviously a better option than treating it.

Experts say there is an obesity epidemic and a major lack of understanding in the community about obesity and its effects and as a medical issue it has not been taken seriously.

A study by obesity expert Professor Louise Baur, found that obesity carried more stigma in children than any physical disability, and was evident across all socio-economic and ethnic groups.

The study found that issues of social acceptance, athletic competence and physical appearance affect obese children and their sense of social and psychological well being and Professor Baur says obese children often have low self-esteem and are more likely to smoke and drink alcohol.

In the search for an explanation's for the surge in obesity worldwide experts suggest that the reasons are complex and multi-factorial, including a mother's diet during pregnancy, genetic susceptibility, and environmental and lifestyle factors.

Dr. Alexander, a specialist in weight management suggests the best approach is a family-focus one which encourages a change in the whole family towards a healthier lifestyle with more healthful eating and more physical activity.