Snack during night shift better than big meal, study finds

The study, conducted by the Sleep and Chronobiology Laboratory at the University of South Australia, involved 44 healthy adults who were observed across seven days.

“The findings will inform the most strategic eating patterns on-shift”

Charlotte Gupta

The participants, who did not normally work night shifts, were made to stay awake overnight and sleep during the day for the purpose of the study.

They were split into three groups with one given a big meal at 12.30am and another given a smaller snack at the same time. The third group was given no food.

The participants were then put through a series of performance tests and asked to provide ratings on how they were feeling.

The study found that those had a snack, which consisted of a muesli bar and an apple, felt more awake than the other two groups, were the most satisfied with the amount of food they had and gave the best mental performance.

One of the tests participants undertook was a driving stimulator. Those in the snack group were found to have faster reactions than those who had a big meal and they also drove more safely by sticking to the speed limit and having fewer crashes.

The study– called Subjective Hunger, Gastric Upset, and Sleepiness in Response to Altered Meal Timing during Simulated Shiftwork – found that having no food was the second-best option for night workers in terms of its effect on performance and alertness.

Lead researcher Charlotte Gupta said the study, published in the journal Nutrients, was the first of its kind and could unlock the secret to the best eating patterns for shift workers to aid performance.

“In today’s 24/7 economy, working the nightshift is increasingly common, with many industries – healthcare, aviation, transport and mining – requiring employees to work around the clock,” she said.

“We know that many nightshift workers eat on-shift to help them stay awake, but until now, no research has shown whether this is good or bad for their health and performance.

“This is the first study to investigate how workers feel and perform after eating different amounts of food,” she said. “The findings will inform the most strategic eating patterns on-shift and can hopefully contribute to more alert and better performing workers.”

All three groups received the adequate number of calories during a 24-hour period, but the time participants ate their main meal varied.

Ms Gupta said the next step would be to examine what type of snacks were best for shift workers.

“We gave people a muesli bar and an apple, which is a fairly healthy snack, but we know that many shift workers are limited in what they can buy, or are getting food from vending machines,” she said.

“There’s also a craving during the middle of the night, when you’re working a hard night shift, for chocolate or something a bit more exciting to eat. So, we want to know what the different types of snack do in how people perform during the night.”

She urged people not to apply the research to eating routines during the day as the human body was programmed to digest food better during sunlight hours.