Three-year-old couch potatoes.

Byline: By John Von Radowitz

Obesity researchers have identified an alarming new British phenomenon - the three-year-old couch potato, it was revealed yesterday.

Tests showed that the children were so inactive they risked becoming grossly overweight.

Similar results were found when the youngsters were tested again at the age of five.

Experts recommend that children of this age engage in at least an hour of moderate to vigorous exercise a day.

But the 78 Scottish three-year-olds who took part in the study were typically active for only 20 to 25 minutes. Their average energy expenditure put them in the "sedentary" lifestyle bracket that increased the risk of obesity, said the scientists.

Study leader Dr John Reilly, from the University of Glasgow, said: "We have provided objective evidence that present recommendations for physical activity are not being met by many young children.

"Low levels of physical activity might have been predicted, but directly measured objective data have not been available and there is a widespread perception among parents and health and educational professionals that young children are spontaneously active.

"Prevalence of childhood obesity in the UK has increased strikingly in recent years.

"Public-health interventions are needed urgently, and these must involve population-based strategies that increase physical activity, reduce sedentary behaviour, or both, in early life."

Unlike their parents and grandparents, today's under-fives have a plethora of TV programmes aimed at their age range featuring characters like the Tweenies and Fimbles.

At the same time they are subjected to advertising for fatty foods, sweets and fizzy drinks.

Neville Rigby, of the International Obesity Task Force, said: "Many more children are playing with computers and electronic games and watching TV.

"They are also exposed to a lot of junk food advertising. Children are being programmed at a very early age into being consumers of fatty and sugary food."

Parents were often to blame for seeking a quiet life at the expense of their children, he said.

"One way of dealing with a fractious child is to sit it in front of the TV with a bag of crisps, but that's wrong," said Mr Rigby.

"Given the chance, children like to go out to play. They should be allowed to enjoy an active life. "

Local authorities were also partly to blame for selling off parks and recreation grounds. "We need a completely different approach to this whole problem," said Mr Rigby.

Dr Reilly's team measured the total energy expenditure (TEE) of the children, as well as looking at their levels of physical activity. Average TEE was found to be about 200 calories a day lower than the UK estimated average requirement for expended energy.

The findings were reported yesterday in The Lancet medical journal. In an accompanying article, James Hill from the Centre for Human Nutrition at the University of Colorado in Denver, US, said: "It is time for the UK to take action to prevent the excessive weight gain that is likely to occur in its young children. Increasing physical activity must be a part of any national prevention efforts for weight gain. Changing behaviour to prevent weight gain will be easier than treating obesity once established. It is time to get serious about prevention of weight gain in the UK."