Forget faddy diets, Dr Atkins and gluten-free recipe books: the key to losing weight might be simply to increase your sleep quota, according to research published today.

Dr Shahrad Taheri, a clinical scientist at Bristol, has found that people who sleep less are likely to be hungrier and consequently may eat more than people who have a healthy eight hours' sleep each night.

Carrying out research in conjunction with colleagues in the United States, Dr Taheri discovered that people who sleep for only five hours a night have 15% more of the hormone ghrelin, which stimulates appetite, and 15% less of the hormone leptin, an appetite suppressant.

"These differences are likely to increase appetite and, in societies where food is readily available, this may contribute to obesity," the research found.

Dr Taheri believes that the time pressures on today's faster-living population is a factor in the drop in hours spent sleeping and the rise in obesity.

"We have to realise that sleeping is not a waste of time, we have to recognise that it impacts on our health. Good sleep, in combination with other lifestyle modifications, may be important in fighting obesity."

The research followed 1,024 adults from the Wisconsin Sleep Cohort Study, a population-based study of sleep disorders. Participants had their sleep monitored and reported on their sleep habits via questionnaires and sleep diaries.