New cases of obesity are rising fastest among younger adults in England, according to a study published in The Lancet. Researchers found that rates of new diagnoses for people in their 30s were nearly 20% higher in 2024-25 than in 2019-20, while those in their 20s saw a 16% increase. These rises outpaced all older age groups, although the most common ages for diagnosis remain the 40s and 50s.
Key Findings by Age Group
The study analyzed 55 million adult NHS patient records, excluding those already recorded as obese. Among those aged 30-39, there were 24.1 new cases per 1,000 people in 2024-25, up from 20.3 in 2019-20. For ages 20-29, new cases rose to 20.3 per 1,000 from 17.5. In contrast, rates fell among those aged 60-79, possibly due to greater access to weight loss drugs, as NHS availability is limited.
Ethnic and Deprivation Disparities
The team also identified significant differences between ethnic groups, with earlier onset of obesity more common in non-white people. Areas with the highest levels of deprivation saw steeper rises. These patterns are well established, but the acceleration in new cases among younger adults was unexpected, the researchers said.
Experts Weigh In on Causes
Lead researcher Robert Fletcher noted three key factors: the boom in unhealthy food markets during the formative years of today's 20- and 30-year-olds, the pandemic, and the cost of living crisis. “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,” he said. The stress of childcare, working from home, and affording healthy food amid inflation has made healthier lifestyles more difficult, he added.
Sarah Perman, from the Association of Directors of Public Health, agreed that unhealthier options now dominate “our supermarkets, corner shops and fast food outlets.” She said children and young people are bombarded with advertising encouraging unhealthy diets, and it is far cheaper to consume foods high in fat, sugar, and salt than healthier alternatives. Research by the Food Foundation found healthy foods are twice as expensive per calorie as unhealthy ones.
Digital and Habit Influences
Katharine Jenner, of the Obesity Health Alliance, said the environment has a huge influence on “habit-forming behaviours.” The digital environment also plays a role, with younger age groups more likely to use food apps and spend time on social media, while the pandemic disrupted physical activity at a “crucial moment.”
The study was conducted by the University of Cambridge, British Heart Foundation Data Science Centre, and George Institute for Global Health. Experts warned the trend towards earlier diagnosis is worrying given obesity increases the risk of diabetes, heart disease, and cancer.
