Monash University study shows shift workers have unhealthier dietary patterns than day employees

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Rotating shift workers consume more calories, indulge in junk food snacks more frequently, and eat less nutritious meals, raising their risk of diet-related illnesses, according to a study from Monash University.

Published in Advances in Nutrition, the comprehensive assessment of dietary behaviour and energy intake research found that rotating shift workers consumed more calories on average over the course of a 24-hour period than day workers.

Also, shift workers reported unhealthier eating habits than day employees, such as inconsistent meal times, increased nighttime snacking or eating, a decrease in the intake of core foods, and an increase in the consumption of discretionary foods.

Monash University PhD candidate and Research Dietitian, Angela Clark, supervised by Professor Maxine Bonham, from the Department of Nutrition, Dietetics and Food compared the total daily kilojoule intake of workers on rotating shift schedules with those on day work schedules and found that rotating shift workers ate on average 264 more kilojoules than regular day workers. 

An increase of just 100 kilojoules each day can lead to a .5 kilogram weight gain over a year, the researchers said. 

In Australia, shift work accounts for 16 per cent of the jobs held by 1.4 million workers, according to the study.

The most typical type of shift work for both men and women is rotating shifts when schedules change from week to week.

Moreover, shift work may be more convenient or more lucrative, but studies have shown that it increases the chance of developing chronic diseases like diabetes and cardiovascular disease.

The time of eating occasions is a role in these elevated hazards, the study claimed.

It stated that a higher percentage of daily calorie intake consumed at night has also been linked to weight gain and compromised glucose metabolism.

Clark, who works with Monash University’s SWIFt Study (Shifting weight in night shift workers) said understanding the impact of extra kilojoule consumption could go a long way towards much-needed workplace support.

She claimed that while the disruption to lifestyle caused by shift work could not be changed, bettering diets and eating habits could.

The study also revealed that compared to day employees, rotating workers’ diets tended to be higher in fat and lower in protein and carbs.

“The foods and drinks typically consumed by rotating workers were more fried and fatty foods, confectionary, sweetened drinks and alcohol, with fewer core foods such as dairy, meat, fruit and vegetables, Clark said. 

Clark also found that there was a tendency of eating more often at night and eating more frequently during the day, with the majority of calories being consumed in the second part of the day.

“Adding to the complexities of nighttime eating, shift workers don’t have the same access to healthy food as day workers and may rely more on vending machines, takeaway and convenience foods,” she added.  

Three weight loss treatments are now being tested for efficacy by Monash University and the University of South Australia in night shift employees.

The NHMRC-funded SWIFt Project examines the impact of complex circadian rhythms and meal timing on successful weight reduction.