Curtailed Sleep Raises Risk of Obesity and Diabetes Researchers have found further experimental evidence that inadequate sleep can increase the risk of obesity and diabetes. A five-week study showed that sleep disruption decreases insulin secretion, increases blood glucose levels and slows metabolism enough to lead to significant weight gain. Scientists kept 24 male and female volunteers in a sleep laboratory for 39 days. After an initial period of normal sleep, the volunteers were put on a schedule by which they slept for 5.6 hours and were kept awake for 21.5 hours, for three weeks. Then the participants had nine days to re-establish normal sleep patterns. Disturbed sleep resulted in a 27 percent average decrease in insulin secretion after eating, and higher glucose levels over a longer period of time, sometimes high enough to make the subject prediabetic. In addition, there was an average 8 percent decrease in resting metabolism rate, a measure of how much energy the body consumes at rest, that translates into a theoretical weight gain of more than 12 pounds a year. Orfeu M. Buxton, the lead author and an assistant professor of medicine at Harvard, said the key for people who must work nights, or rapidly change time zones, is to "get better sleep during the day by sleeping in a dark, silent, cool room." The study appeared last week in Science Translational Medicine.