London, May 5: The fond hope that puppy fat will melt away as children leave their adolescent years is nothing but a myth, researchers have found.

A study of nearly 6,000 London children shows that obesity is established by the age of 11, with a quarter of all boys and girls classed as overweight or obese.

Few of these overweight or obese children slimmed down to a normal weight between the ages of 11 and 16.