A recent Australian study published in Diabetologia reveals that night shift workers who eat during their shift could face higher risks of long-term health issues, such as diabetes and heart disease.
Researchers from the University of South Australia, the University of Adelaide, and the South Australian Health and Medical Research Institute (SAHMRI) conducted a six-day trial to investigate the impact of meal timing on blood sugar control during night shifts.
The study involved 55 healthy adults with normal body weights who don’t usually work night shifts.
During the trial, participants were asked to stay awake for four nights, sleep during the day, and follow one of three eating plans: fasting at night, having light snacks, or eating full meals.
After a recovery day on the fifth day to return to normal routines, their blood glucose levels were tested on the sixth day to observe the effects.
Results showed that participants who ate either full meals or snacks during their night shift had significantly poorer glucose tolerance, meaning their blood sugar levels were harder to control.
In contrast, those who fasted overnight had improved insulin secretion, helping keep their blood sugar levels balanced.
Professor Leonie Heilbronn from SAHMRI and the University of Adelaide noted that the people who ate meals or snacks experienced a spike in blood sugar, while those who fasted did not face the same issue.
“Shift workers are at higher risk of conditions like diabetes and heart disease, and our study suggests that eating at night could be a key factor,” said Professor Heilbronn.
“Our bodies naturally release insulin after meals to help muscles and tissues absorb glucose. But if insulin resistance occurs—often because of circadian rhythm disruptions from night shifts—glucose can build up, leading to long-term risks like diabetes.”
The research also found that all participants, regardless of diet, experienced some insulin sensitivity disruption. This result highlights how night shifts themselves misalign the body’s natural rhythm, impairing glucose management.
Lead researcher Professor Siobhan Banks from the University of South Australia suggests that simply avoiding large meals at night might be a simple way for night shift workers to help protect their health.
“Eating only during the day could be more manageable than complex diets, offering a straightforward way to improve health outcomes,” she says.
The research team is planning future studies to determine whether small protein-based snacks at night might help satisfy hunger without increasing health risks. This could provide a balanced solution for night shift workers seeking both health and comfort while working overnight.
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