New cases of obesity are increasing at their fastest rate among younger adults in England, according to a major new study that highlights growing concerns over the nation’s long-term public health trajectory. Researchers have identified a significant rise in obesity diagnoses among people in their twenties and thirties, raising alarms about the future burden of chronic diseases such as diabetes, cardiovascular conditions and cancer.
The findings, published in The Lancet, reveal that adults aged between 30 and 39 experienced the sharpest increase in new obesity diagnoses over the past five years. Researchers found that obesity incidence within this age group rose by nearly 20% between 2019-20 and 2024-25. Among adults aged 20 to 29, the increase reached 16%, marking one of the most substantial rises across all demographic categories.
While obesity remains most commonly diagnosed among people in their forties and fifties, experts warn that the accelerating trend among younger adults could have far-reaching consequences for both individual health outcomes and the wider healthcare system.
Growing Public Health Concern
Health specialists have described the findings as particularly concerning because obesity is a major risk factor for a wide range of serious medical conditions. Individuals living with obesity face a significantly increased likelihood of developing type 2 diabetes, heart disease, stroke, certain cancers and musculoskeletal disorders.
The emergence of obesity at a younger age may also result in prolonged exposure to these health risks throughout adulthood, increasing the likelihood of long-term complications and greater demand on NHS services.
Researchers noted that the trend toward earlier obesity diagnoses appears to be accelerating, especially among younger generations who have grown up in an environment characterised by widespread availability of highly processed foods, intensive marketing of unhealthy products and increasingly sedentary lifestyles.
Researchers Identify Possible Drivers
Although the study did not directly investigate the causes behind the increase, experts involved in the research pointed to several contributing factors that may explain the rise among younger adults.
Lead researcher Robert Fletcher suggested that people currently in their twenties and thirties have spent much of their lives exposed to an increasingly unhealthy food environment. Over recent decades, high streets across the country have seen a significant growth in takeaway outlets and fast-food establishments, while advertising for foods high in fat, sugar and salt has become increasingly prevalent.
According to Fletcher, these environmental influences may have shaped dietary habits during critical developmental years, making unhealthy food choices more common and accessible.
In addition, researchers believe the lasting effects of the COVID-19 pandemic and the subsequent cost-of-living crisis may have disproportionately affected younger adults. Many individuals in this age group faced heightened financial pressures, childcare responsibilities and lifestyle disruptions during lockdown periods, all of which may have contributed to weight gain and reduced opportunities for physical activity.
Impact of Food Environment and Economic Pressures
Public health experts have long argued that the UK’s food environment plays a significant role in rising obesity levels. Sarah Perman, representing the Association of Directors of Public Health, said unhealthy food options now dominate many retail and food service settings.
She highlighted concerns that children and young people are regularly exposed to marketing campaigns promoting unhealthy foods and beverages. At the same time, healthier alternatives often remain more expensive and less accessible for families facing financial constraints.
Research conducted by the Food Foundation has previously shown that healthier foods can cost approximately twice as much per calorie as less nutritious options. This disparity creates significant barriers for households attempting to maintain balanced diets amid ongoing economic challenges.
Experts also point to the growing influence of digital technology. Food delivery applications, targeted online advertising and increased screen time may all contribute to changing dietary behaviours, particularly among younger generations who are more engaged with digital platforms.
Study Based on 55 Million NHS Records
The research team, comprising specialists from the University of Cambridge, the British Heart Foundation Data Science Centre and the George Institute for Global Health, analysed approximately 55 million adult NHS patient records.
To ensure accuracy, researchers focused specifically on individuals receiving a new obesity diagnosis, excluding those who had already been classified as obese before the study period.
Among adults aged 30 to 39, the rate of new obesity diagnoses increased from 20.3 cases per 1,000 people in 2019-20 to 24.1 cases per 1,000 in 2024-25. For those aged 20 to 29, rates rose from 17.5 to 20.3 cases per 1,000 people during the same period.
By contrast, some older age groups experienced slower growth or even slight declines in new obesity diagnoses. Researchers suggested that greater access to weight-management treatments, including private weight-loss medications, may partly explain this trend among older adults.
Overall, the proportion of adults recorded as living with obesity increased from 26.2% to 30.3% during the study period, demonstrating the continuing expansion of obesity across England’s population.
Inequalities Remain Deeply Entrenched
The study also identified significant disparities linked to ethnicity and socioeconomic status. Earlier onset obesity was found to be more common among non-white populations, while communities experiencing higher levels of deprivation recorded steeper increases in obesity diagnoses.
Experts say these findings reinforce longstanding concerns about health inequalities across England. Communities facing economic disadvantage often encounter greater barriers to accessing nutritious food, safe recreational spaces and preventative healthcare services.
Professor Sir Michael Marmot, a leading authority on health inequalities, described the findings as further evidence that disparities have widened in the years following the pandemic.
He warned that rising obesity rates among younger adults could deepen existing inequalities unless targeted interventions are introduced to address the social and environmental factors driving poor health outcomes.
Government Response and Future Action
In response to the findings, the Department of Health and Social Care said the government is taking decisive action to tackle obesity and improve public health outcomes.
Current measures include introducing tighter restrictions on junk food advertising and establishing targets designed to encourage healthier food sales. Ministers have argued that a comprehensive approach involving industry, healthcare providers and local communities is essential to reversing current trends.
Nevertheless, public health experts maintain that broader structural reforms may be required. Many argue that addressing obesity effectively will depend on creating healthier food environments, improving affordability of nutritious options and expanding access to preventative health initiatives.
As obesity continues to rise across England, the study underscores the urgency of tackling the issue among younger generations. Without sustained intervention, experts warn that increasing numbers of young adults could face decades of preventable health complications, placing growing pressure on individuals, families and the NHS alike.