A MONASH University-led clinical trial has found intermittent fasting (IF) could offer night shift workers a more flexible and effective approach to weight loss and metabolic health compared with traditional continuous energy restriction (CER).
Published in The Lancet’s eBioMedicine, the SWIFt study investigated the effectiveness of two IF strategies—both variations of the 5:2 diet—against CER among 250 night shift workers over 24 weeks.
Participants were assigned to consume 2100 kilojoules per day—about 25 per cent of their usual intake—on two non-consecutive days a week, either during night shifts or on days off, while eating normally the rest of the week. Their results were compared to those on a continuous daily calorie restriction diet.
Professor Maxine Bonham, who led the research, said night shift workers often face significant dietary challenges due to eating during circadian off-peak times, contributing to weight gain and heightened type 2 diabetes risk.
“Due to their work schedules, night shift workers have little choice but to eat at times of the day normally associated with sleeping, and because of this weight gain and an increased risk of developing type 2 diabetes are recognised consequences of night shift work,” she said.
“By testing the effectiveness of two 5:2 strategies compared with continuous energy restriction… we can improve night shift worker health.” Professor Bonham said participants found intermittent fasting more manageable and adaptable to shift schedules, especially given the limited nighttime food options often restricted to takeaway or vending machines.
“For the first time we have shown that the 5:2 diet offers an alternative approach to improving metabolic health, including blood pressure, body weight and insulin resistance, in night shift workers that may be more flexible for their lifestyle.”
The researchers say their findings could pave the way for updated dietary guidelines tailored specifically to shift workers, offering new hope for reducing chronic disease risks.
