HONG KONG children are bigger and heavier than ever before, pushing them into the high-risk zone for diabetes, high cholesterol levels, strokes and heart disease. And they are reaching puberty faster - usually before they finish primary school - according to the first large-scale growth study of 25,000 children conducted since 1963. As well as fatty food, one of the main causes of the weight gain may be more homework - leaving less time for outdoor exercise. Chinese University, the Hospital Authority and Department of Health jointly carried out the territory-wide study of babies, toddlers, children and young adults to the age of 25. Their findings have prompted the medical research team to give up their weekends and working hours to visit schools and warn children to slim down before disease hits. Chinese University Department of Paediatrics lecturer Dr Gary Wong Wing-kin said the first such study, completed 32 years ago, set the 'normal' growth standards against which the new findings were compared. The team went to 18 districts in Hong Kong and took a wide range of measurements. 'We now have a complete set of data from which to construct a growth chart . . . compared to 30 years ago, both boys and girls are maturing a lot earlier.' Girls now began menstruating at 12, but were sexually developing by nine. About three per cent were developing breasts by seven. Previously, most girls began menstruating at 13 years but developed breasts at 10. 'With the boys, about three per cent showed signs of sexual maturation around eight years,' Dr Wong said. Most boys were sexually developed at 11, a two-year advance on the boys of 1963. 'And if you look at the boys, on average they weigh six to eight kilograms heavier than 35 years ago, right across the board,' he said. Plentiful food was triggering the early onset of puberty, which caused pre-teens to shoot up in height. Today's eight to 11-year-olds were four to six centimetres taller than the 1960s generation, but slowed to retain a height advantage of just two centimetres by age 18. 'It's simple; if your nutritional status is good, you're prepared to be a mum or a dad earlier,' Dr Wong said. 'But what is more worrying . . . is their weight. 'Boys and girls are going to have diabetes, high blood pressure, more heart attacks and strokes. These will not manifest at such a young age, but will cause problems. 'Doctors are seeing lots of new referrals of obese children, and obesity is very hard to lose. We find the majority of kids gaining weight dramatically between four and eight years of age.' As children went through primary school, they were burdened with more homework, leaving less time for outdoor exercise. Parents often bribed their offspring to study or do homework with promises of special food. 'And the fast food doesn't help,' Dr Wong said, warning that the children would go on gaining weight with age. 'And if they've gained four to eight kilograms by age 18, then by age 50 they will be 10 to 15 kilograms overweight.' The average weight of a boy of 18 is up 18 per cent on 32 years ago, while his height has increased two per cent. Girls of 18 are 11 per cent heavier than their 1960s counterparts and one per cent taller. Dr Wong and his colleagues are so concerned at the prospect of a generation of overweight heart disease candidates they have begun speaking at Urban and Regional Council events, visiting schools and encouraging children, some as young as five, to watch their weight. 'It's a very difficult battle because the pharmaceutical industry and the so-called nutrition companies are not supportive,' he said. 'We're not going to get funding from a pharmaceutical company that makes diabetic drugs. We're using our own time to go out to schools and so on; the major thing is time.'