Scientists have drawn up a check-list of early warning signs of child obesity, among them too much television and not enough sleep.

More than eight hours' TV a week or less than 10-1/2 hours' sleep a night for a three-year-old increase the risk of piling on the pounds, they say.

"Eight factors in early life are associated with an increased risk of obesity in childhood," said Dr John Reilly, an expert on child obesity at the University of Glasgow. "There are certain factors, very early on, which can set you on a particular path in life to becoming obese," he added in an interview.

The others are: high birth weight; early size; rapid weight gain; quick growth in years one and two; early body fat; and having obese parents.

A propensity to gain weight begins early, even in the womb.

"If you are big early on and you grow rapidly, it seems to predict risk of obesity later on," said Reilly. "There is something about size and growth, even in the womb, that seems to have an effect."

By the tender age of three, children are developing habits that will mean they are more likely to be overweight or obese.

"We shouldn't be complacent about the lifestyles of our children," Reilly said. "What our study is showing is that although there are early growth risk factors, there are also a number of risk factors that relate to lifestyle, of three-year-olds and probably earlier, that seem to make a difference."

He and his colleagues, whose findings were reported online by the British Medical Journal, studied more than 9,000 children aged seven whose growth had been followed since birth.

Health experts estimate that about 10 percent of children, or at least 155 million youngsters worldwide, are overweight or obese.

Overweight and obese children have a higher risk of suffering from type 2 diabetes and, later in life, of developing heart disease, stroke and certain types of cancer.

Reilly stressed that efforts to prevent obesity should begin very early in life.

"We are missing an opportunity to prevent obesity if we do not modify lifestyle and environment early in life. We need to be looking more at improving long-term outcomes by changing lifestyle," he added.

SOURCE: BMJ Online First, May 20, 2005.