New diagnoses of obesity are increasing most rapidly among adults in their 20s and 30s in England, according to a study published in The Lancet and reported by the BBC.
What the figures show
The study, which analysed 55 million adult NHS patient records, found that rates of new obesity diagnoses among people aged 30 to 39 were nearly 20% higher in 2024-25 than they were in 2019-20. Among those in their 20s, new cases rose by 16% over the same period, the steepest increases of any age group examined.
In absolute terms, new diagnoses among 30 to 39-year-olds stood at 24.1 per 1,000 people in 2024-25, up from 20.3 in 2019-20. For those aged 20 to 29, the rate rose from 17.5 to 20.3 per 1,000 people over the same five-year span.
By contrast, rates of new diagnoses actually fell among those aged 60 to 79. Researchers suggested this could be linked to the use of weight-loss drugs, noting that older age groups were more likely to be able to afford them given restricted NHS access.
Overall, the proportion of people recorded as obese rose from 26.2% to 30.3% during the period studied.
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Why younger adults are seeing steeper rises
Lead researcher Robert Fletcher, while noting the study did not investigate causes directly, pointed to three key factors. He said adults now in their 20s and 30s had grown up during a period of rapid expansion in the unhealthy food market, with a "proliferation of takeaways and fast food outlets" on high streets and heavy advertising of unhealthy food during their formative years.
Fletcher also cited the pandemic and the subsequent cost of living crisis as likely contributors, arguing these had a disproportionate impact on younger adults, particularly those managing childcare and working from home while facing rising food costs.
Sarah Perman, from the Association of Directors of Public Health, said unhealthier options now dominated "our supermarkets, corner shops and fast food outlets", and that children and young people had been "bombarded with advertising that encourages an unhealthy diet" from infancy. She added that foods and drinks high in fat, sugar and salt were far cheaper and easier to access than healthier alternatives.
Research by the Food Foundation, cited in the BBC's report, found healthy foods are twice as expensive per calorie than unhealthy foods.
Inequality and ethnicity
The research team, drawn from the University of Cambridge, the British Heart Foundation Data Science Centre and the George Institute for Global Health, also identified significant differences between ethnic groups, with earlier onset of obesity more common among non-white people. Areas with the highest levels of deprivation also recorded steeper rises in new cases.
Professor Sir Michael Marmot, from University College London, described the findings as concerning and said they were "further evidence" that inequalities had widened since the pandemic.
Government response
A Department of Health and Social Care spokesperson told the BBC the government was taking "decisive action" on obesity, pointing to new restrictions on junk food advertising and targets on healthy food sales.
Experts quoted in the report said the acceleration of new cases among younger adults was more unexpected than the broader patterns around deprivation and ethnicity, which they described as well established.
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