Chan says women who are so overweight that they are technically obese can have a 170 percent higher chance of infertility than usual. She says increasing numbers of women were being treated for infertility at the Queen Mary Hospital, the University of Hong Kong's teaching hospital, which admits 1300 patients a year with infertility problems compared to 300 a year in 1993.

Chan says obesity is one of the factors and one in four Hong Kong women is now either overweight or obese.

She adds that overweight women are more likely to have miscarriages, having a 15 percent chance compared with an 11 percent chance among women of normal weight.

Experts blame the rising levels of obesity in Hong Kong in the past three decades on the switch to a more Western diet, long office hours and sedentary lifestyles.

"But research has shown that children can learn to like foods more if they try them often enough. So providing healthy foods in schools would make a valuable contribution to improving children's diets in the future."

Richard Davidson, director of public affairs for Cancer Research UK said: "Education on healthy eating in schools is essential. Teachers throughout the country should be given information on the best way to help children learn about the advantages of eating fruit and vegetables and the effects of being seriously overweight. Practical lessons on how to prepare healthy food could be useful as an informal approach."

Top ten foods for girls were:

Chocolate Strawberries Fruit juice Pasta Pizza Ice Cream Grapes Ice lollies Chocolate biscuits Cakes

Top ten foods for boys were:

Pizza Chocolate Ice cream Choc biscuits Fruit juice Ice lollies Fizzy drinks Pasta Cakes Crisps

British Journal of Nutrition

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