Not having a regular sleeping pattern could have an adverse effect on our health. So says a study published in The European Journal of Nutrition this week. The study suggests irregular sleeping patterns could increase the abundance of harmful species of bacteria in the gut. Altering the time we sleep on workdays and at weekends causes a shift in our internal body clock. Researchers call this "social jet lag". It leads to a poorer quality diet, with a higher consumption of sugary snacks, and lower intakes of fruit and vegetables. Study author and nutrition scientist Dr Kate Bermingham said: "Social jet lag can encourage [bacteria] species which have unfavourable associations with your health."

The effects of social jet lag are like those of jet lag we get after long airline flights. Jet lag is extreme tiredness and other physical effects caused by flying across different time zones. After a long flight, sufferers often opt for unhealthy comfort foods. Social jet lag can be more problematic, as it is ingrained in our daily routines. It can elevate the risk of diabetes, heart problems, and weight gain. The researchers say a 90-minute difference between sleeping and waking times can send the body's biological rhythms into disarray. Another nutritionist said: "Maintaining regular sleep patterns…is an easily adjustable lifestyle behaviour we can all do, that may impact your health via your gut…for the better."