BABIES who are breastfed for longer and weaned on to solids later are less likely to suffer childhood obesity, a study has revealed.
Researchers found the risk of a nine-year-old being obese was reduced by 51pc if breastfed for six months or more, compared with an exclusively formula fed child.
Infants breastfed for three to six months were 38pc less likely to be chronically overweight by nine, they added.
The findings are based on the Growing Up in Ireland report, which previously revealed a quarter of nine-year-olds are rated overweight or obese, at 19pc and 7pc respectively.
Professor Richard Layte said factors including parental weight, status, lifestyle, exercise and diet were also taken into account.
"Obesity is a serious problem in Ireland," said Prof Layte, of the Economic and Social Research Institute (Esri).
"We have some of the highest rates of child and adult obesity in Europe and we need to understand the causes better.
"Our study suggests that early life nutrition may be a key issue for improving health and reducing obesity."
Growing Up in Ireland is a Government-funded study following the progress of almost 20,000 children from nine months to 13 years.
It found Ireland has the lowest breastfeeding rate in Europe, with 55pc of new mothers breastfeeding to some extent. Only 38pc still breastfeed after a month and less than 15pc for six months.
About 46pc of infants are weaned on to solid foods by four months and less than a third are weaned after six months - a guideline set by the World Health Organisation.
Researchers warned obese children are more likely to become obese adults and suffer a range of chronic diseases including coronary heart disease, diabetes and stroke.
"Increasing rates of breastfeeding and later weaning would reduce obesity rates among children in Ireland and improve population health and life expectancy in future decades," they found.
Children's Minister Frances Fitzgerald said the short-term benefits of breast feeding are well recognised.
"This research adds to the growing evidence that the benefits of breastfeeding extend to later life," she said.
"Breastfed babies have a better chance of avoiding obesity in later childhood.
"If we are to reverse the worrying trend of childhood obesity in Ireland, promoting and increasing rates of breastfeeding must be part of our policy response."