Study finds daytime meals may reduce health risks linked to night shift work - National Institutes of Health

A small clinical trial supported by the National Institutes of Health has found that eating during the nighttime—like many shift workers do—can increase glucose levels, while eating only during the daytime might prevent the higher glucose levels now linked with a nocturnal work life.

The findings, the study authors said, could lead to novel behavioral interventions aimed at improving the health of shift workers – grocery stockers, hotel workers, truck drivers, first responders, and others – who past studies show may be at an increased risk for diabetes, heart disease, and obesity.

“This is a rigorous and highly controlled laboratory study that demonstrates a potential intervention for the adverse metabolic effects associated with shift work, which is a known public health concern,” said Marishka Brown, Ph.D., director of the NHLBI’s National Center on Sleep Disorders Research.

After a preconditioning routine, the participants were randomly assigned to a 14-day controlled laboratory protocol involving simulated night work conditions with one of two meal schedules.

The researchers found that nighttime eating boosted glucose levels – a risk factor for diabetes – while restricting meals to the daytime prevented this effect

Specifically, average glucose levels for those who ate at night increased by 6.4% during the simulated night work, while those who ate during the daytime showed no significant increases

“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,” said study leader Frank A.J.L

They believe that the nighttime eating effects on glucose levels during simulated night work are caused by circadian misalignment

The work further suggests the beneficial effects of daytime eating on glucose levels during simulated night work may be driven by better alignment between these central and peripheral “clocks.”

“This study reinforces the notion that when you eat matters for determining health outcomes such as blood sugar levels, which are relevant for night workers as they typically eat at night while on shift,” said the study co-leader Sarah L

To translate these findings into practical and effective meal timing interventions, the researchers said more study is needed, including with real-life shift workers in their typical work environment.   

Daytime eating prevents internal circadian misalignment and glucose intolerance in night work