People who work longer hours are more likely to be obese, according to new research presented at the European Congress on Obesity in Istanbul. Experts are now calling for Britain to consider a four-day working week as the study shows countries with longer working hours have higher obesity rates.
Research Highlights Link Between Work Hours and Weight Gain
The study, conducted by Dr. Pradeepa Korale-Gedara of the University of Queensland in Australia, suggests that lack of time for exercise and work-related stress may explain why those who work late are more prone to weight gain. Workplace stress increases cortisol levels, which can lead to fat storage, while many modern jobs involve sedentary tasks that do not burn energy.
Dr. Korale-Gedara stated: “There is a debate in Australia about four-day weeks. I have seen research looking at possible productivity gains… but now people are looking at it from a different perspective. I think this is something that can be considered. When people have a more balanced life, they have a better life. They have less stress, they can focus on more nutritious food and engage in more physical activities.”
Mechanisation and Convenience Food Contribute to Problem
Manual jobs in developed nations have become increasingly mechanised, meaning workers on long hours find it difficult to burn enough calories while relying more on convenience foods. The study found that countries like the United States and Latin American nations, which tend to work longer hours, also have higher obesity rates. This held true even though northern European countries consume more energy and fat on average than Latin American countries.
Researchers analysed data from 33 OECD countries between 1990 and 2022, finding that a 1% reduction in annual working hours was associated with a 0.16% decrease in obesity rates. With three in ten Brits classified as obese, a four-day week—representing a 20% reduction in working hours—could be linked to around half a million fewer obese individuals. However, the study does not prove causation, and income levels may also play a role.
Stress and Weight Gain: The Biological Mechanism
When stressed, the body releases cortisol, which triggers glucose release from the liver into the bloodstream—a survival mechanism evolved for physical threats. In modern sedentary settings, such as sitting at a desk, this glucose is not used and may be converted into fat. Chronic stress keeps cortisol levels elevated, leading to cravings for high-calorie, sugary foods and reducing the body's ability to burn fat. Late-night work can disrupt sleep, increasing appetite-driving hormones the next day.
The NHS recommends managing stress through exercise, deep breathing, and planning ahead for stressful days.
Growing Movement Towards a Four-Day Week
There is increasing momentum in the UK and other developed nations for a four-day working week. Proponents argue that productivity can be maintained while achieving wider societal benefits. The previous Conservative government opposed the idea, but Labour ministers like Angela Rayner have expressed support. A 2022 UK pilot by the 4 Day Week Foundation involving 3,000 employees saw 56 of 61 companies reduce hours from five days.
Dr. Rita Fontinha, a psychologist at Reading University, who has received funding from the Portuguese government to pilot a four-day week, commented: “We know that obesity is related to lower incomes but also to time poverty. If you work two jobs or long hours, you simply do not have the energy to cook and it becomes easier to buy packaged or processed food. A four-day week could lead to better choices in food, exercise, and sleep, contributing to healthier societies.”
Historical Context and Future Outlook
The four-day week movement draws parallels to the shift from a six-day to a five-day working week a century ago, driven by trade unions and the Great Depression. Campaigners argue that as artificial intelligence increases productivity and makes some roles redundant, a shorter working week will become more necessary. Office for National Statistics data shows over 200,000 workers have already moved to a four-day week since the COVID-19 pandemic.
James Reeves, campaign manager of the 4 Day Week Foundation, said: “A four-day week on full pay could slash Britain’s obesity levels by giving millions the time they need to ditch bad habits and make healthier choices. When we asked staff what they did on their additional day off, the most common answer was 'life admin', including food shopping, which frees up weekends for healthy activities. It's essential that local and national government consider the role of a shorter working week in improving community health. The 9-to-5, five-day week is 100 years old and long overdue an update.”
On May 1, campaigners gathered outside Ford Motor Company’s Dagenham plant to mark the 100-year anniversary of it becoming the first company to adopt a five-day week. A government spokesperson said: “This government will not mandate a four-day work week for five days’ pay but through the Employment Rights Act, we’re making it easier for flexible working requests to be accepted.”
