A new study presented at this year's European Congress on Obesity (ECO 2026) in Istanbul, Turkey (12-15 May) shows that a 1% reduction in annual working hours is associated with a 0.16% decrease in obesity rates across OECD countries. The study is led by Dr Pradeepa Korale-Gedara, University of Queensland, Brisbane, Australia and colleagues.
Adult obesity remains a major public health challenge across OECD countries, with significant health, social, and economic implications. Public health research has overwhelmingly focused on dietary patterns, activity levels, and individual behaviours as drivers of obesity. While this has led to major advances in knowledge in many areas such as nutrition, human metabolism, and psychology, researchers are increasingly looking to structural determinants to make effective interventions. Food environments and time poverty have long been understood as factors that negatively affect nutrition and activity levels, the role working hours plays as a driver of obesity, however, has been gathering significant momentum in recent years.
In this new study the authors investigated the link between working hours and obesity rates in the context of a wider range of determinants compared with existing studies using data for 33 OECD countries over the period 1990 – 2022.
Preliminary analysis of the dataset surprisingly showed that average energy and fat intake reported at the national level were not well correlated with national obesity rates. For example, energy and fat intake in Latin American countries in the OECD are far lower than European countries such as Norway, Spain, France, Denmark, and Austria, yet the Latin American countries have far higher rates of obesity.
The prevalence of obesity varies dramatically among OECD nations. As of 2022, the United States reported the highest adult obesity rate among the 30 OECD countries with data at 41.99%, while Japan had the lowest at 5.54%. Several countries including Chile, Mexico, and New Zealand also exhibit high obesity rates, exceeding 30%, whereas several European nations, particularly in Northern and Western Europe, maintain rates below 20%, with the UK between these extremes at 26.8%. (See links to editor)
As of 2022, of the 32 countries with data analysed, the lowest working hours per year were Germany (1340), Norway (1422), Belgium (1422), Sweden (1436), and the Netherlands (1450). The UK was in the lowest 10 countries, with 1505, while the USA was in the 10 highest with 1811. The five countries with the highest were Colombia with 2282, Mexico (2226), Costa Rica (2149), Chile (1966) and Israel (1891).
To account for potential gender-specific effects, the analysis is conducted separately for males and females. In addition, subsample analyses were performed for the periods 1990–2010 and 2000–2022* to assess how relationships between factors may have evolved over time. The data are drawn from publicly available sources, including the OECD, WHO, FAO, and the World Bank.
Using computer modelling, the researchers found that between 1990-2022, a 1% reduction in annual working hours is associated with a 0.16% decrease in obesity rates across whole populations. When the data is divided by sex the impact of reduced working hours is stronger in men, where a 1% reduction in annual working hours is associated with a 0.23% decrease in obesity rates, compared with 0.11% for women.
The effects of working hours on obesity were shown to vary over different periods. Looking at the earlier period of study, 1990-2010, a 1% reduction in annual working hours is associated with a 0.17% decrease in obesity rates across the whole population. When males and females are assessed separately, this reduction in working hours is associated with a 0.24% decrease in obesity rates for men and 0.17% decrease for women.
Analysis of the period from 2000-2022 shows a 1% reduction of working hours was associated with a 0.13% decrease in obesity rates across the whole population. In this time period the 1% reduction in working hours was associated with a 0.12% decrease in obesity rate for men and a 0.17% reduction for women.
The authors say these results show that the impact of working hours on obesity was more pronounced during the earlier period (1990–2010) than in more recent years. They believe that policy interventions and increased public health awareness may have contributed to a slower rate of obesity after 2000. The literature also provides support for this explanation. Additionally, changes in social norms may have played a role. As obesity rates increased, increasing cultural awareness and promotion of healthy behaviours relating to nutrition and exercise have likely offset some of the factors driving obesity rates.
Higher income levels were also linked to lower obesity prevalence, with a 1% increase in GDP per capita associated with a 0.112% reduction in obesity (0.16% for men and 0.11% for women). Urbanisation also plays a role, albeit with a smaller effect - a 1% increase in urbanisation (the proportion of population living in urban areas) was associated with a 0.02 decrease in obesity (in both men and women). These associations are non-linear however, with factors linked to national cultures and differences in infrastructure playing an important role.
The authors say: "These patterns point to potential mechanisms such as reduced time for physical activity, increased work-related stress, and greater reliance on energy-dense convenience foods. Higher GDP per capita, greater urbanisation, and higher food prices were negatively associated with adult obesity prevalence, suggesting that improved economic conditions, more supportive urban environments, and higher relative food costs may facilitate healthier dietary choices.
On the overall results they say: "The findings suggest that the relationship between working hours and obesity is complex and influenced by various socio-economic and cultural factors. Longer working hours create time constraints that may lead to unhealthy dietary choices and reduced physical activity. As noted earlier, extended working hours may also induce psychological stress, contributing to stress-related eating and elevated cortisol levels—both of which are associated with weight gain."
"These results underscore the need for coordinated policy responses that extend beyond individual behaviour change. Addressing obesity effectively requires an integrated approach that considers labour market dynamics, urban design, and food system governance. Policy interventions aimed at improving work–life balance, promoting active transportation, and fostering healthier food environments may play a critical role in mitigating obesity risk."
They conclude: "This research underscores the critical role of working hours in shaping obesity rates across OECD countries. It advocates for policies that prioritise public health by regulating working hours, enhancing leave entitlements, and fostering healthier food environments. Future research should explore the interplay between work demands and health-related behaviours to better understand the complexities of obesity prevention."
