Obesity affected nearly a third of adults in England in 2025, new research suggests. The study by researchers from the University of Cambridge, the British Heart Foundation Data Science Centre at Health Data Research UK and The George Institute for Global Health also revealed the most disadvantaged groups are bearing a disproportionate burden of the obesity crisis, and this gap has widened in the wake of the COVID-19 pandemic.
This study is the first to analyse obesity trends from 2019 to 2025, using NHS England electronic health records covering nearly 55 million adults. The scale and detail in the data allowed the researchers to gain new insight into how rates of new obesity cases recorded by healthcare professionals, and the percentage of people affected by obesity differ by sex, age, socioeconomic status, ethnicity, and geographical region.
Robert Fletcher of the University of Cambridge, Health Data Research UK and The George Institute, and study co-lead said that levels of obesity in England have worsened since the pandemic, with nearly one in three people now affected.
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We’re also seeing large disparities across the country: the percentage of adults affected by obesity in northeast England is six times higher than in central London. Differences on this scale are rarely seen in other areas of public health. The rise in new cases among young adults of childbearing age is especially concerning. Beyond the implications for their own long-term health, obesity is associated with infertility, adverse pregnancy outcomes, and child obesity, which may perpetuate intergenerational cycles of health inequality.
By:Robert Fletcher
Research Associate, The George Institute for Global Health
University of Cambridge, Health Data Research UK
Key findings:
Obesity is rising: Rates of new obesity cases increased overall by 4% in 2025 compared with before the COVID-19 pandemic.
Young adults hit hardest: The largest increases over time were seen in younger adults. Rates of new obesity cases rose by almost 20% in those aged 30-39, and by 16% in those aged 20-29, while rates fell among adults aged 60-79.
Risk rises with deprivation: Over the study period, rates of new obesity cases were 35% higher for people with the highest socioeconomic deprivation (those with the lowest incomes, highest unemployment, and poorest housing) compared with people with the lowest socioeconomic deprivation. The gap was wider still for women, where new cases were 54% higher among the most deprived, and widest for Asian women, at 94% higher.
Ethnicity and deprivation compound: The percentage of people living with obesity ranged from 4% among the most affluent White men aged 18-19 to 66% among the most socioeconomically deprived Black women aged 60-69 – nearly double the figure for the least-deprived White women of the same age.
Large geographical differences: The percentage of people affected by obesity in some areas of northeast England (48%) was nearly six times higher than that seen in the most affluent parts of central London (8.5%). The steepest increases over time were seen in areas with the lowest GDP per capita.
The person-level data analysed in this study has all direct identifiers such as names and NHS numbers removed before researchers access the data, which is then only accessible within NHS England’s Secure Data Environment. The data is only accessible by approved researchers working on approved, COVID-19 related research projects.
The researchers’ definition for obesity was a recorded body-mass index (BMI) of 30 or above, or a clinician’s diagnosis of obesity in a person’s health records. Their findings from this electronic health record study correspond well with the NHS Health Study for England, which samples households across the country, giving confidence in the extra depth of the insights this study is able to provide.
They looked at rates of new cases of obesity (incidence) and the percentage of people with obesity (prevalence) in the general population, as well as differences across sociodemographic groups and geographical regions.
Obesity is now more common than hypertension (high blood pressure) in the UK, and nearly three times as common as smoking. It is a chronic, complex disease linked with a whole host of conditions, including heart disease, stroke, cancer, diabetes, and kidney failure. As well as affecting individuals’ mental wellbeing and placing growing pressure on both the healthcare system and the economy. These findings highlight the scale and urgency of the obesity crisis, and how it has worsened since the COVID-19 pandemic.
GLP-1 receptor agonist drugs, like Ozempic/Wegovy and Mounjaro, are known to be effective in managing obesity and are being more widely prescribed and used. The study did not set out to examine their impact.
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We don’t see any obvious reduction in obesity in our data following the introduction of GLP-1 receptor agonists, at least not within the current study period.
However, the drugs on their own are unlikely to be the answer. At present, the majority are privately prescribed and the jabs are expensive, which poses a barrier for people from disadvantaged backgrounds. We need deep-seated change to the many social and economic factors that drive obesity in the first place.
By:Robert Fletcher
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Obesity is not primarily about will power. These new, powerful data indicate that those most at risk frequently reside in the most obesogenic environments and likely have the least agency to withstand such environments. To achieve lasting change, the UK must expand access to new treatments faster but also fundamentally reshape food and activity environments so that healthier choices occur with minimal conscious effort. Failure to act will drive further rises in multimorbidity and human suffering, with profound consequences for the NHS and the wider economy.
By:Naveed Sattar
Professor of Cardiometabolic Medicine at the University of Glasgow and Chair of the Obesity Health Care Goals Programme
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The COVID-19 pandemic has had a lasting impact on health and lifestyle behaviours. By analysing electronic health records from the entire adult population of England before, during, and after the pandemic, we have generated the most comprehensive evidence to date on how obesity risk and burden are increasingly diverging across multiple dimensions of inequality. These findings underscore the critical importance of secure access to whole-population health data to enable research, surveillance, and timely action to address widening health inequalities.
By:Angela Wood
Professor at the University of Cambridge and Associate Director at the British Heart Foundation Data Science Centre
The study, funded by the Wellcome Trust, Health Data Research UK, the British Heart Foundation, the National Institute for Health and Care Research Cambridge Biomedical Research Centre, the Cambridge British Heart Foundation Centre of Research Excellence, has been published in The Lancet Diabetes & Endocrinology.
