Irregular sleeping patterns could adversely affect our health. So says a study in The European Journal of Nutrition. The study suggests sleeping at different times could increase the number of harmful species of bacteria in our stomach. Changing the times we sleep on workdays and at weekends changes our internal body clock. Researchers call this "social jet lag". It leads to eating more sugary snacks, less fruit and vegetables, and a poorer diet. The lead author of the study said social jet lag can encourage bacteria that are bad for our health.

The effects of social jet lag are like those of jet lag we get after long airplane flights. After a long flight across different time zones, people often eat unhealthy comfort foods. However, social jet lag can be more problematic, as it is part of our daily routines. It can increase the risk of heart problems and weight gain. The researchers say a 90-minute difference between sleeping and waking times can have a bad effect on the body's biological rhythms. A scientist said sleep patterns were easy to adjust. She said this would be good for our health.