Catching up on sleep at the weekend puts people at risk of gaining excess weight, according to a new study.

Experiments found that those who do not sleep enough during the week but who snatch extra hours at the weekend tend to snack more and have an increased risk of diabetes.

The effects were worse even than those who are sleep-deprived during the week but who did not catch up at the weekend.

Conducted by the University of Colorado Boulder, the study shows that consistent adequate sleep is crucial for controlling appetite and maintaining metabolic health, its authors said.

They enlisted 36 healthy adults aged between 18 and 39 to stay for two weeks in a laboratory where their food intake, light exposure and sleep were monitored.

The participants were divided into three groups. One group enjoyed nine hours’ sleep a night for nine consecutive days, while another was allowed just five hours' a night over the same period. The third group was given five hours’ sleep a night for five nights and were then allowed to sleep as much as they liked over a weekend, before returning to restricted sleep for two days.