Girls ‘Naturally Fatter’ Than Boys

Girls are naturally 60% fatter than boys by the age of 18, researchers said yesterday.

A two-year study of almost 2,000 children aged five to 18 used a technique to measure both total body mass and body fat to see how fat levels changed as youngsters get older.

The researchers found that on average, by the age of 18, 15.4% of boys’ body mass was fat compared with 24.6% in girls.

They said that as children grew up, girls continued to gain fat after puberty, while boys gained more muscle and lean tissue.

It is hoped the new body fat reference curves, developed using bioelectrical impedance analysis (BIA) technology, will help give more accurate indications of obesity than body mass index (BMI) which looks at weight compared to height.

Professor Andrew Prentice, from the London School of Hygiene and Tropical Medicine, said that currently around 25% of children could be misclassified as either overweight or of normal weight because BMI did not differentiate between fat and muscle. He said that as it stood, a very fit and muscular youngster could be classified as obese.

‘BMI measures weight, it does not measure body fat and it is the body fat that is causing tissue damage and raising blood pressure and the risk of diabetes,’ he said.

Researcher Dr David McCarthy of London Metropolitan Univer- sity, said the gender difference they found confirmed a ‘normal biological phenomenon’ – that girls have a greater proportion of body fat for reproduction.