Obesity in girls has been linked to the early onset of puberty in a review of over 100 earlier research projects.
Leader of the study Professor Emily Walvoord found that obese young women tended to reach puberty before their peers of a healthy weight.
Professor Walvoord, of the Indiana University School of Medicine, commented: "Early puberty is one of the many outcomes of obesity.
"There are clearly other factors we don't understand that have affected the timing."
The report, which was published in the Journal of Adolescent Health, revealed difficulties in untangling the effects of early puberty, such as depression and body image issues, due to their similarity with those of obesity.
Obesity is affecting an increasingly large proportion of children in the UK.
The latest figures from the NHS Information Centre revealed that 11.1 per cent of boys aged between two and 15 and 12.2 per cent of girls were classified as obese in 1995.
However, by 2008 these numbers had risen to 16.8 per cent and 15.2 per cent respectively.