THE study in Denmark of 280,000 people born between 1930 and 1976 also found that fat boys are far more likely to get heart disease as adults than fat girls.

The risk is higher if the boy is obese at the age of 13 than if he was obese at age seven but had slimmed down.

The Institute of Preventive Medicine team in Copenhagen found that a 13-year-old boy of average height who is 11.2kg heavier than the norm has a 33 per cent higher risk of getting coronary heart disease when he grows up.

An accompanying commentary by Associate Professor David Ludwig of Harvard Medical School predicts that childhood obesity would shorten lives in the United States by two to five years by mid-century - 'an effect equal to that of all cancers combined'.