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Eating at nighttime — as many shift nurses do — can increase glucose levels, while eating only during daytime hours may have a preventative effect, according to a trial backed by the National Institutes of Health.

Led by Frank A.J.L. Scheer, Ph.D., professor of medicine at Harvard Medical School and director of the Medical Chronobiology Program at Brigham & Women’s Hospital in Boston, researchers randomly assigned 19 healthy participants to 14 days of simulated night work with one of two meal schedules. One group ate during the nighttime to mimic a meal schedule typical among night workers, and one group ate during the daytime.

The nighttime eating boosted glucose levels, while restricting meals to daytime prevented this effect. High blood glucose is associated with diabetes and heart disease risks.

“This is the first study in humans to demonstrate the use of meal timing as a countermeasure against the combined negative effects of impaired glucose tolerance and disrupted alignment of circadian rhythms resulting from simulated night work,” Scheer said. Findings were published in the journal Science Advances.