Researchers from Oregon State University found that obesity could be related to growing problems with infertility in addition to a host of other physical and psycho-social concerns.
The study was published in journal Frontiers in Endocrinology.
"The issue of so many humans being obese is very recent in evolutionary terms, and since nutritional status is important to reproduction, metabolic syndromes caused by obesity may profoundly affect reproductive capacity," Patrick Chappell, an assistant professor at the University said.
"Either extreme of the spectrum, anorexia or obesity, can be associated with reproduction problems," he said in a statement.
One theory for early onset of puberty in girls was the impact of obesity on kisspeptin, a recently characterised neurohormone necessary for reproduction.
Normal secretions of this hormone may be disrupted by endocrine signals from fat that serve to communicate to the brain, the study found.
Another possible affect on pubertal timing, and reproduction in general, is disruption of circadian clocks, which reflect the natural rhythms of night and day.
Disrupted sleep-wake cycles can affect the secretion of hormones such as cortisol, testosterone, and insulin, researchers found.