Breastfeeding does not seem to protect babies against becoming overweight or obese children, according to a European study that included more than 10,000 mothers and babies.
"It's just a reality check that in itself, promoting breastfeeding, while a good thing that will have other health benefits, is unlikely to have any effects on stemming the obesity epidemic," said lead author Richard Martin, from the University of Bristol, UK.
Past research has suggested that babies who are breastfed are less likely to grow up to be obese children, but those studies compared mothers who chose whether or not to breastfeed, so they and their children could have been different in other important ways, researchers said.
The study, which appeared in Journal of the American Medical Association, included 17,000 mothers and their infants in Belarus. About half the babies were born at maternity hospitals that used a World Health Organisation-designed initiative to promote breastfeeding.
All mothers originally breastfed their babies, so the study was meant to compare how long infants were breastfed, rather than whether they were breastfed at all, Martin said.
The programme to encourage breastfeeding seemed to work. By three months out, 43 per cent of mothers who gave birth at intervention hospitals were still exclusively breastfeeding, compared to six per cent of women in the comparison group.
Martin said that over the years, his team's study has found fewer stomach infections and eczema and better thinking and memory skills among kids in the breast-feeding promotion group.
In this stage of the trial, however, the researchers compared weight and body fat in about 14,000 children who were tracked through age 11 and found no differences tied to breastfeeding. Between 14 and 16 per cent of all the children were overweight and about five per cent were obese.
Other researchers, though, said they still felt that starting breastfeeding in the first place can help ward off obesity.
Ruth Lawrence, a breastfeeding researcher from the University of Rochester Medical Center in New York, said past studies have shown that breastfed babies have more appetite control than those started on formula, for example.
"Of course it's disappointing that there wasn't a dramatic difference," Lawrence, who wasn't involved in the story, told Reuters Health.
Others said the current study doesn't detract from the importance of breastfeeding, given its other known benefits for mothers and babies.
"Maybe we shouldn't be touting breastfeeding as an obesity prevention method, but it's still important," said Alison Ventura, a nutrition scientist at Drexel University in Philadelphia.
She recommended that new parents learn about when they should introduce certain foods to their baby's diet, and in what portions, as part of thinking about promoting healthy growth long-term.
"Breastfeeding is just one factor, and maybe studies like this suggest that it's not just one factor that is going to reduce obesity rates, it's probably more the combination of factors," she said.