Shift workers including nurses and midwives who eat a small snack during a nightshift perform better than those who opt for a large meal, new research has revealed.

Investigating the impact of eating during the night on work performance, the study found having a small snack such as an apple or muesli bar helps shift workers stay more alert and primed to carry out their jobs than a large meal or no food at all.

Led by PhD Candidate Charlotte Gupta, at the University of South Australia’s Sleep and Chronobiology Laboratory, the study put 44 healthy people on a nightshift schedule in the sleep laboratory for seven days and examined outcomes based on their food intake.

At 12.30am during each night shift, participants ate a snack such as a muesli bar or handful of nuts, a large lunch-type meal, typically a sandwich, or nothing at all.

They then undertook 40 minutes on a driving simulator, completed a series of reaction time tasks, and had their mood measured.

Each participant consumed the same amount of food every day but some ate during the night and others did not.

Findings showed people who ate a large meal during the nightshift experienced impaired performance characterised by slower reaction times, difficulty sticking to the speed limit and staying in their lane, and a higher likelihood of crashing.

They were also sleepier, more restless, angrier, and suffered greater gastric upset.

Those that ate the small snack during the nightshift performed best, reacting faster and driving safer compared to participants who ate the large meal or nothing at all.

In some aspects of performance, eating nothing also proved better than a large meal.

Worryingly, those that ate the large meal performed even worse at 7am, seven hours after eating, indicating many shift workers could be at further risk during the commute home.

The study, which built on initial research that looked at the impact of eating a large meal during shift work versus nothing at all, recommends shift workers choose a small snack during the nightshift to maintain their performance.

According to recent data from the Australian Bureau of Statistics (ABS), in 2009 there were 1.4 million shift workers in Australia.

Of these, 32% worked in health care and social assistance, while about 16% of all shift workers worked evening shifts.

Ms Gupta said shift workers such as nurses often deal with critical tasks such as assisting patients or administering medications and that the study represented an important exploration.

“There’s really been no research on what happens if you eat at night on performance and whether it’s a good thing or a bad thing,” Ms Gupta explains of the study’s objective.

“Given that many shift workers who are awake during the night are eating it seemed like an important question for us to answer.”

Ms Gupta said the research evidence supports advising shift workers to choose a snack over a large meal to perform better and make it through the night.

However, she acknowledged shift workers in professions such as nursing and midwifery face challenges due to food habits, food availability, and culture.

Subsequent research is likely to focus on different types of snacks and their impact, she added.

“Some shift workers might be going for the apple or muesli bar option but a lot are going for things like chocolate bars or chips from the vending machines or the break room. That’s often all they can get during the night,” she said.

“So the next step would be to look at different types of snacks and if an unhealthier snack is worse for performance or if a snack that’s unhealthier but more comforting to eat, such as chocolate, could actually be better for performance.”