Obesity Cases Increasing Fastest in Younger Adults
New obesity diagnoses are increasing most rapidly among younger adults in England, according to a recent study.
The study, published in The Lancet, found that rates of new obesity diagnoses among people in their 30s were nearly 20% higher in 2024-25 compared to 2019-20. For those in their 20s, new cases rose by 16% during the same period.
These increases outpaced those seen in older age groups, although the most common ages for obesity diagnosis remain in the 40s and 50s.
Experts have expressed concern about this trend toward earlier diagnosis, noting that obesity elevates the risk of conditions such as diabetes, heart disease, and cancer.
In addition to age-related differences, the research team identified significant disparities among ethnic groups, with earlier onset of obesity more prevalent in non-white populations. Areas with higher deprivation levels also experienced steeper increases.
While these patterns of obesity are well documented, the acceleration in new cases among younger adults was unexpected, according to the researchers.
Why the Rapid Rise?
Lead researcher Robert Fletcher explained that although the study did not explore the causes behind the increase, he identified three key contributing factors.
"Adults in their 20s and 30s grew up during a period marked by a boom in the unhealthy food market," Fletcher said. "They have been surrounded by unhealthy food in their formative years. On our high streets, there has been a proliferation of takeaways and fast food outlets, and unhealthy food has been heavily advertised as these age groups have been growing up."
He also noted that the COVID-19 pandemic followed by the cost of living crisis likely had a greater impact on younger adults.
"The stress of looking after children while working from home, combined with rising inflation making healthy food less affordable, has made maintaining healthier lifestyles more difficult," he added.
Sarah Perman from the Association of Directors of Public Health concurred, emphasizing the dominance of unhealthier food options.
"Unhealthier options now dominate our supermarkets, corner shops, and fast food outlets," Perman said. "From infancy, children and young people are bombarded with advertising that encourages an unhealthy diet. It is also far cheaper and easier for individuals to consume foods and drinks high in fat, sugar, and salt than healthier alternatives."
Research by the Food Foundation has found that healthy foods cost twice as much per calorie as unhealthy foods.
Katharine Jenner of the Obesity Health Alliance highlighted the influence of the environment on younger adults' habits.
"The environment people in their 20s and 30s have grown up with has had a huge influence on habit-forming behaviours," Jenner said. "The digital environment likely plays a role as well, with younger age groups more likely to use food apps and spend time on social media. The pandemic disrupted physical activity and other habits at a crucial moment."
Obesity Prevalence and Diagnosis Rates
The research team, comprising members from the University of Cambridge, British Heart Foundation, and George Institute for Global Health, analyzed 55 million adult NHS patient records to identify new obesity diagnoses, excluding individuals already recorded as obese.
Among those aged 30 to 39, there were 24.1 new cases diagnosed per 1,000 people in 2024-25, compared to 20.3 per 1,000 in 2019-20.
For those aged 20 to 29, new cases rose to 20.3 per 1,000 from 17.5 per 1,000 five years earlier.
These represented the most rapid increases across all age groups. Conversely, rates of new diagnoses declined among those aged 60 to 79.
Researchers suggested this decline in older adults could be related to the use of weight loss medications, which these age groups are more likely to afford, especially given restricted NHS access.
Overall, the proportion of people recorded as obese increased from 26.2% to 30.3% during the study period.
Professor Sir Michael Marmot of University College London, a leading expert on inequality, described the findings as concerning.
"This is further evidence of how inequalities have widened since the pandemic," Marmot said.
A spokesperson from the Department of Health and Social Care stated that the government is taking "decisive action" on obesity, including implementing new restrictions on junk food advertising and setting targets for healthy food sales.
