Research presented at the European Congress on Obesity has found a link between longer working hours and higher obesity rates across developed nations. The findings have prompted renewed debate in the UK over whether shorter working weeks could improve public health.
The international study analysed data from 33 OECD countries between 1990 and 2022 and found that countries with longer annual working hours tended to record higher obesity levels. Researchers said the relationship may be connected to stress, reduced time for exercise and greater reliance on processed food.
The issue has gained attention as more British employers experiment with four-day working weeks. According to Office for National Statistics data cited by several campaign groups, more than 200,000 UK workers have moved to four-day schedules since the Covid-19 pandemic.
Researchers involved in the study stressed that the findings do not prove direct causation. Income levels, national lifestyles and broader economic conditions may also influence obesity trends across different countries.
Researchers Identify Link between Work Patterns and Obesity Rates
The study, led by Dr Pradeepa Korale-Gedara of the University of Queensland, compared obesity prevalence with annual working hours across OECD countries. According to the research presented in Istanbul, a 1% reduction in annual working hours was associated with a 0.16% decrease in obesity rates.
Countries including the United States, Mexico and Colombia, where employees generally work longer hours, were found to have higher obesity rates than several northern European countries. Researchers noted this trend appeared even though northern European populations often consume more energy and fat on average.
Dr Korale-Gedara said work-related stress could contribute to increased levels of cortisol, a hormone linked to fat storage. She also said many modern jobs involve little physical movement, while long working hours leave people with less time to prepare healthy meals or exercise regularly.
“When people have a more balanced life, they have a better life,” she said during the congress in Istanbul. “They have less stress, they can focus on more nutritious food and engage in more physical activities.”
The research also highlighted changes in the nature of work over recent decades. According to the findings, jobs that were previously more physically demanding have become increasingly mechanised, while office-based roles now involve prolonged periods of sitting in front of screens.
The researchers cautioned that the study identifies correlations rather than proof that long working hours directly cause obesity. They said factors such as income inequality and national differences in diet and lifestyle could also play a role.
Four-Day Week Campaigners Point to Health and Lifestyle Benefits
The findings have been welcomed by campaigners supporting shorter working weeks in Britain. According to the 4 Day Week Foundation, reducing working hours could help people spend more time cooking, exercising and managing daily responsibilities.
James Reeves, campaign manager at the organisation, said a four-day week “could slash Britain’s obesity levels by giving millions the time they need to ditch bad habits and make healthier choices”.
A large UK pilot involving around 3,000 employees in 2022 saw 56 of 61 participating companies reduce staff working hours from a traditional five-day schedule. Supporters of the policy argue that productivity can be maintained while improving workers’ wellbeing.
Dr Rita Fontinha, a psychologist at the University of Reading who has researched four-day working patterns, said obesity is linked not only to income but also to what she described as “time poverty”. According to Dr Fontinha, people working multiple jobs or long hours may lack the energy to cook and instead rely on packaged or processed food.
Government ministers have continued to reject proposals for a nationally mandated four-day week with no loss of pay. A government spokesperson said ministers would instead focus on making flexible working requests easier to approve through employment legislation.
Critics have also questioned the conclusions drawn from the study. Dr Christopher Snowdon of the Institute of Economic Affairs argued that Britain already ranks among countries with relatively low average working hours while still recording high obesity rates.
