The problem with toddlers is that we now have a situation where many mothers work, come home and need to do the housework so sit their children in front of the television or video.

Dr Peter Bundred, Liverpool University

They also discovered that 9.2% of the children were classed as obese - compared with 5.4% the previous decade.

They found that the heights of the children being studied were not changing and Dr Bundred warned that the trend could have long term health repercussions.

Childhood years

"We know that teenagers have become fatter but for the first time we are seeing rapid increases in weight throughout the childhood years.

"That is worrying, as obesity is linked to problems such as heart disease and premature death.

Healthy snacks for your child

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"Of course, not all overweight children will be overweight teenagers and adults, but a significant proportion of them may have ongoing weight problems in later life," he said.

Dr Bundred said parents needed to start rethinking their lifestyles and that of their children.

"The problem with toddlers is that we now have a situation where many mothers work, come home and need to do the housework so sit their children in front of the television or video.

"People are also eating a lot more ready meals which have a higher fat content.

Ready meals

"We need to encourage mothers to look carefully at the fat content of the food they are giving their children, and toddlers need to be up and about playing and running around to ensure they get enough exercise," he said.

His views were echoed by Professor Stephen Bloom, and expert in child nutrition from Hammersmith Hospital, London.

He said: "Lots of studies show that if you are fat when you are young, you are fat when you are old. We are growing a population of obese adults."

Catherine Collins, Chief Dietician at St.George's Hospital, London and a spokeswoman for the British Dietetic Association said that although the figures in the study were bleak that they still meant most children were not over weight.

She said parents must look carefully at the fast food their children eat and try and boost their exercise levels.

"Bear in mind that the majority of the children within this survey are still not overweight, so the majority of carers must be getting it right," she said.