British researchers say a study involving more than 1,000 volunteers suggests that a reduction in the amount of sleep people may result in hormonal changes that could partly account for soaring obesity rates.

"Individuals who spent less than eight hours sleeping were shown to have a greater likelihood of being heavier," reported Dr. Shahrad Thaeri of the University of Bristol.

His report, published in the journal Public Library of Science Medicine, was one of three published in recent weeks that arrived at a similar finding.

The University of Bristol study found that people who habitually slept for five hours had 15 percent more ghrelin, a hormone which increases feelings of hunger, than those who slept for eight hours. Those who slept for less time were also found to have 15 percent less leptin, a hormone which suppresses appetite.

"These differences are likely to increase appetite and, in societies where food is readily available, this may contribute to obesity," Taheri said. "It is important for people to realise there is more to obesity than just stuffing your face."

A study published earlier by University of Chicago researchers found that people who slept for only four hours a night for two nights had an 18 percent reduction in leptin, and a 28 percent increase in ghrelin. The young men in the study also tended to eat more sweet and starchy foods when sleep was cut short.

A third recent study by Columbia University researchers also found found people who slept four hours or less per night were 73 percent more likely to be obese.

Other sources: Public Library of Science Medicine