Working shifts other than the typical 9 a.m. to 5 p.m. is putting people at increased risk of obesity and diabetes, according to a study at Brigham and Women's Hospital that controlled the eating and sleeping schedules of 21 individuals, reported BBC News.
Changes to normal sleeping patterns make it difficult for the body to control sugar levels, state the results published in Science Translational Medicine.
Study participants began by sleeping 10 hours per night, followed by three weeks of disruption to their sleep and body clocks. It only took weeks for some to develop early symptoms of diabetes.
Researchers re-calculated a day to 28 hours to simulate the effect of jet lag. In the new 28-hour day, participants were allowed to sleep 6.5 hours (equivalent to 5.6 hours in a normal 24-hour day). They also lived in dim light to avoid bright light resetting their body clocks.
Blood sugar levels "significantly increased" immediately following a meal and during "fasting" parts of the day. The body also produced lower levels of insulin, the hormone that manages blood sugar.
Three trial participants' blood sugar spiked so drastically after their meals that they were classified as pre-diabetic. They also faced a heightened risk of weight gain, researchers noted.
"We think these results support the findings from studies showing that, in people with a pre-diabetic condition, shift workers who stay awake at night are much more likely to progress to full-on diabetes than day workers," said lead researcher Dr. Orfeu Buxton.
Following the study, the research team has recommended measures be implemented to reduce the negative effects of shift work.