Scientists have revealed why people should head to sleep at the same time every night. A study by Kings College London which involved 1,000 adults, aimed to find whether "social jetlag" (the shift between sleep patterns on work days and free days) can have an impact on health. In doing so, researchers discovered that sleeping at the same time and a healthy diet could decrease the risk of disease. They found that even a 90-minute difference in the mid-point of sleep could impact the types of bacteria in the gut. They analysed participants' sleep, blood and stool samples, and logged everything they consumed in a food diary. Those with "social jetlag" (16 per cent) appeared to have a diet filled with potatoes, crisps, chips and sugary drinks. Other studies have suggested that social jetlag is linked to weight gain, illness and mental fatigue. Sign up for our free Indy100 weekly newsletter Dr Wendy Hall, senior author from King’s College London, said: "We know that major disruptions in sleep, such as shift work, can have a profound impact on your health. "This is the first study to show that even small differences in sleep timings across the week seems to be linked to differences in gut bacterial species. "Some of these associations were linked to dietary differences but our data also indicates that other, as yet unknown, factors may be involved. "We need intervention trials to find out whether improving sleep time consistency can lead to beneficial changes in the gut microbiome and related health outcomes." Kate Bermingham, study author and senior nutrition scientist at ZOE, said: "Sleep is a key pillar of health, and this research is particularly timely given the growing interest in circadian rhythms and the gut microbiome. "[Social jetlag] can encourage microbiota species which have unfavourable associations with your health," she continued. Have your say in our news democracy. Click the upvote icon at the top of the page to help raise this article through the indy100 rankings.