Just playing with a Barbie doll once can make young girls think they need to be thin, according to new research.
A study published in the journal Body Image found that the dolls made girls as young as five think that being skinny was ideal.
Body image expert Marika Tiggerman said parents should avoid giving the dolls to girls.
'If girls already have Barbies then parents should encourage them to do more than just make them look pretty.'
Professor Tiggerman said among the girls sampled, Barbie promoted internalisation of the thin ideal.
'This means they think appearance is important and in particular being skinny is good. If fat is bad, then thin is good, and thinner is better.'
However Mattel, which makes Barbie, rejected the research findings and said it had released a range of Barbies with different body shapes.